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As the highest peak on the earth, Mt. Qomolangma provides an unparalleled platform to study glacier‐atmosphere interaction. Although glacier surface energy balance (SEB) on Mt. Qomolangma was examined during warm season, relevant knowledge during cold season is still unknown, which prevents a complete understanding of all‐season glacier SEB on it. Based on an in‐situ observation from October 2007 to January 2008, this study presents a cold‐season glacier SEB result at 6,523 m above sea level on Mt. Qomolangma and identifies its atmospheric control. Our results show that the observational period experienced strong winds and deficient clouds. Near‐surface wind speeds usually exceeded 10 m s−1, resulting in a substantial sensible heat transport toward glacier and thus enhancing outgoing longwave radiation, which, under the combined effect of deficient clouds, eventually caused an increase in longwave radiative loss. The large solar zenith angle and relatively high albedo of the glacier surface led to a small absorption of solar irradiance, which, in combination with the strong longwave radiation loss, resulted in a semi‐permanent surface radiative loss. Uncommon over the highly reflective glacier surface, clouds decreased the incident solar radiation more than increased the longwave radiation, demonstrating that the clouds' shading effect surpassed its greenhouse effect. As a vital heat sink, the turbulent latent heat induced an average sublimation rate of 0.8 mm water equivalent per day. This study provides valuable insights into the atmospheric control on the cold‐season glacier‐atmosphere interaction at high altitudes on Mt. Qomolangma when meteorological variables are subject to the westerlies. Plain Language Summary: Mt. Qomolangma is the highest mountain on the earth. Qomolangma's glacier retreat is a warning sign for rapid climate warming. Understanding the atmospheric control on Qomolangma's glacier mass loss is critical. This paper thoroughly examines how the energy associated with Qomolangma's glacier mass loss at 6523 m above sea level was governed in the cold season. We find that wind speed is an important factor. On one hand, its increase enhanced the energy input toward glacier, increasing surface temperature and thus letting more energy escape from glacier surface under the combined influence of small cloud cover; on the other hand, the increase in wind speed enhanced the mass loss of sublimation, lowering surface temperature. Cloud cover is another factor. The clouds' shading effect of decreasing incoming sunlight surpassed its greenhouse effect of increasing energy toward glacier, making less energy arriving at the glacier surface and thus decreasing mass loss. Additionally, at the highly reflective glacier surface, glacier received weak sunlight in cold season because a significant portion of the relatively modest incoming sunlight was reflected to the sky. These results provide valuable insights into the atmospheric control on Qomolangma's glacier mass loss in the cold season. Key Points: We present 3.5 months of autumn and wintertime glacier surface energy balance at 6,523 m above sea level on Mt. QomolangmaThere was a semi‐permanent surface radiative loss due to deficient clouds, large solar zenith angle, and high albedo of glacier surfaceClouds reduced solar irradiance more than increased longwave radiation, implying that their shading effect surpassed the greenhouse effect [ABSTRACT FROM AUTHOR]

The Asian tropopause aerosol layer (ATAL) has emerged in recent decades with aerosol accumulation near tropopause above Asian Summer Monsoon region. Although ATAL effects on surface and top‐of‐atmosphere (TOA) radiation budgets are well established, the magnitude and variability of ATAL effects on radiative transfer within the tropopause layer remain poorly constrained. Here, we investigate the impacts of various aerosol types and layer structures on clear‐sky shortwave radiative heating in the Asian monsoon tropopause layer using reanalysis products and offline radiative transfer simulations. ATAL effects on shortwave radiative heating based on the Modern‐Era Retrospective Analysis for Research and Applications, version 2 aerosol reanalysis are on the order of 15% of mean clear‐sky radiative heating within the tropopause layer, although discrepancies among recent reanalysis and forecast products suggest that this ratio could be as small as ∼10% or as large as ∼70%. Uncertainties in surface and TOA flux effects are also large, with values spanning one order of magnitude at the TOA. ATAL effects on radiative heating peak between 150 and 80 hPa (360–400 K potential temperature) along the southern flank of the anticyclone. Clear‐sky and all‐sky shortwave heating are at local minima in this vertical range, which is situated between the positive influences of monsoon‐enhanced water vapor and the negative influence of the "ozone valley" in the monsoon lower stratosphere. ATAL effects also extend further toward the west, where diabatic vertical velocities remain upward despite descent in pressure coordinates. Plain Language Summary: Every summer, a layer of polluted air laden with aerosol particles collects above the convective storms of the Asian monsoon as part of a broad upper‐level circulation centered over the Tibetan Plateau. Researchers have developed a working understanding of how the dynamical environment shapes this Asian tropopause aerosol layer (ATAL). The motivating question for this work is: How might the aerosol layer reshape its environment? Aerosols can absorb and scatter sunlight, affecting both the amount of sunlight transmitted through the layer and the magnitude of solar heating within the layer. These effects depend on aerosol species and their vertical distribution within the layer, both of which are highly variable. In this paper, we translate variations and uncertainties in the amount, composition, and vertical distribution of aerosols near the Asian monsoon tropopause into variations and uncertainties in the absorption and scattering of solar radiation by the aerosol layer. We find that aerosols account for a substantial part (10%–70%) of heating by solar radiation near the tropopause in the region of ATAL. The vertical location and horizontal extent of the aerosol effects are distinct from those of other radiative effects. Key Points: The Asian tropopause aerosol layer produces a 10%–70% direct enhancement of clear‐sky shortwave heating above the summer monsoonEffects are largest where shortwave heating is weakest, with similar magnitudes to water vapor and ozone effects near the monsoon tropopauseDiscrepancies across recent aerosol analysis and forecast products cause large uncertainties in aerosol forcing of heating and fluxes [ABSTRACT FROM AUTHOR]

The spatial pattern of intermodel spread of surface temperature (TS‐SPREAD) is similar to the absolute error of modeled surface temperature relative to observations, implying the possibility of using intermodel spread to understand the model biases. The regions with maximum TS‐SPREAD are located in the northern polar (NP) and southern polar (SP) regions, and regions with the large orographic features, such as the Tibetan Plateau (TP). We find: (a) Winter amplification exists in the TS‐SPREAD over both the NP and SP regions, but the maximum TS‐SPREAD over the TP happens during spring and summer with weak seasonality there. (b) Surface energy balance analyses show salient land‐sea contrast in the interlinkage between the physical processes. (c) Over the Arctic Ocean and the Southern Ocean, the maximum spreads of sea‐ice‐induced surface albedo appear during summer when the TS‐SPREADs are the weakest because the effect of surface albedo is offset by the heat storage in the oceans. (d) Through the interseasonal linkage of the heat storage term, i.e., the summer‐storing‐winter‐releasing of oceanic heat content, the summer surface albedo may indirectly contribute to the winter amplification of the TS‐SPREAD over the polar oceans. Such interseasonal linkage of the processes does not exist over the land areas. A method of distinguishing the roles of the local and nonlocal dynamical processes in the contribution of the clear‐sky downward longwave radiation to the TS‐SPREAD is also provided. Plain Language Summary: Understanding the origin of climate model biases is essential to the projection of future climate change, and it is very hard task for the climate modeling community. Here, we show that there exists similarity in the spatial patterns of the intermodel spread, mean absolute errors, and absolute mean errors of surface temperature simulations in climate ensembles. Therefore, we may use the intermodel spread to help understand the mean model biases. We find the regions with maximum surface temperature spread (TS‐SPREAD) are mainly located in the northern polar (NP) and southern polar (SP) regions, and regions with large orographic feature, such as the Tibetan Plateau, indicating the polar and topographic amplifications of TS‐SPREAD in climate models. In the paper, we reveal the process‐chains that lead to the spatial pattern and seasonality of amplified TS‐SPREAD over these regions. We suggest that sea‐ice contributes to the TS‐SPREAD over the NP and SP oceans, not in a direct way, but by its coupling with ocean storage, interseasonal heat release through turbulent fluxes, and also the horizontal heat transport, both across the border of and inside the polar regions. The findings may help climate modelers to improve their models. Key Points: The pattern‐similarity among intermodel spread, mean absolute bias, and absolute mean bias enable us to use the former to understand the latter twoThe interseasonal linkage between surface albedo, heat storage, turbulent fluxes, and dynamical transport causes winter amplification over polar oceansA method is provided to determine the local versus nonlocal contributions to surface downward longwave radiation [ABSTRACT FROM AUTHOR]

Climate warming causes permafrost degradation that not only leads to the release of greenhouse gases to the atmosphere, but also to soil moisture increases due to ground ice melt. These processes are particularly prevalent in peat‐rich and ice‐rich permafrost regions. Peat is important because of its high organic matter content and soil moisture. Although previous work has focused on the importance of two factors, their precise quantitative impact on permafrost is still not clear. Here we apply the Geophysical Institute Permafrost Laboratory model and sensitivity experiments to quantify the role of organic matter and soil moisture on permafrost, with a case study focused on the northeastern Tibetan Plateau. We verify that organic matter and soil moisture has a cooling effect in the warm season and an insulating effect in the cold season. The average thawing onset was delayed 10 days at 0.05–1.4 m depths, when organic matter content increases from 0% to 90%. Freezing onset occurs slightly earlier. Furthermore, active layer thickness (ALT) decreased by 0.40 m. Soil moisture has similar effect on permafrost as organic matter, but ALT changes have a higher magnitude, decreasing by 0.46 m. The results show that both organic matter and soil moisture have an insulating effect on permafrost. Further, the magnitude of impact is larger as organic matter or soil moisture increase. These results can be helpful in assessing permafrost carbon mitigation with climate change. Plain Language Summary: Permafrost can contain high amounts of organic matter and ground ice, and peat plays an important role in permafrost degradation. Permafrost degrades due to climate warming, which can lead to the release of carbon in the form of greenhouse gases, exacerbating the degradation of permafrost. Additionally, soil moisture also significantly impacts permafrost degradation. However, few studies have estimated the effects of organic matter and soil moisture on permafrost degradation. This paper therefore explores the quantitative effect of organic matter and soil moisture on permafrost through a series of model sensitivity experiments. We find that organic matter and soil moisture both insulate permafrost, cooling it in summer and warming it in winter. These results are important for mitigating the effects of climate change on permafrost and carbon feedbacks. Key Points: The insulating effect of organic matter and soil moisture on permafrost is quantified using model sensitivity experimentsIncreasing organic matter and soil moisture both cool permafrost in summer and warm it in winterThese organic matter and soil moisture feedbacks refine our understanding of permafrost dynamics under climate change [ABSTRACT FROM AUTHOR]

Lower atmospheric gravity waves (GWs) can significantly impact waves in the middle and upper atmospheres and are vital for turbulence generation. This paper puts the spotlight on the spatial–temporal variability of tropospheric GW total energy (ET) and its potential sources above four regions of interest (ROIs) gathered from high‐resolution radiosonde observations from the China Radiosonde Network during the years 2016–2019. The seasonality of ET above four ROIs shows different characteristics and is dependent on latitudes and underlying terrains, reaching its maximum identified in the winter at middle latitudes. Interestingly, the annual cycles of the maximal ET shift from 35°N in October to 25°N in March of the next year, triggered by the shift in the winter subtropical jet. Based on the random forests regressor, the jet stream between 200 and 125 hPa likely serves as the primary source for the observed GWs above the ROIs with low and middle latitudes, with relative contributions of around 60%. However, the Kelvin–Helmholtz instability between 800 and 125 hPa could be the most recognized source of GWs and contributes around 68.4% to the observed energy. During the rainy season, the ET under scenarios of convective precipitation is around 20% larger than the other. As well, as the near‐surface or low‐level wind interacts with a mountain barrier over the Tibetan Plateau region, 12.4% of the observed ET is attributed to the strength of the low‐level wind. Plain Language Summary: The gravity wave (GW) is one of the most important waves in the atmosphere and acts as a triggering source to turbulence. However, the tropospheric GWs in the context of China has seldomly been investigated by using high‐resolution radiosonde data set. This analysis shows that the GW total energy exhibit obvious seasonal various at low and middle latitudes, with maximal identified in the winter and minimal in the summer. The jet stream in the upper troposphere is the most important source for GW at low and middle latitudes and gives rise to a southward propagation of the maximal GW energy in cold season. In the summer of southern China, the convective precipitation could contribute to the enhancement of GW energy. In addition, 12.4% of the observed GW energy is attributed to the strength of the low‐level wind over the Tibetan Plateau. Key Points: Jet stream is the dominant source for gravity waves (GWs) at low and middle latitudes and triggers southward movement of GW energy core during cold seasonsOver the Tibetan Plateau, Kelvin–Helmholtz instabilities and terrain‐induced flows contribute to the intensive GW activitiesDuring the summertime of southern China, convective precipitation could contribute to the enhancement of energy of about 20% [ABSTRACT FROM AUTHOR]

The physicochemical properties and origins of atmospheric aerosols in the Tibetan Plateau (TP) region are a research topic of great interest, but an in‐depth understanding of this topic is challenging, partially due to a lack of intensive in situ observations. Thus, a field campaign was conducted over Yadong, a remote area on the south slope of the TP from June 11 to 31 August 2021. The aerosol loading was low, with a black carbon mass concentration of 147.4 ± 98.4 ng·m−3. Aerosol single‐scattering albedo was low (0.73 ± 0.11 at 550 nm) and increased from 450 to 700 nm wavelength. Organic matter (OM) accounting for 69.6% of the total aerosol mass and relatively high secondary organic carbon ratios, highlighting the importance of secondary formation. An interesting phenomenon observed was that the evolution of aerosols was mainly characterized by diurnal variation, which could not be explained by large‐scale atmospheric processes such as Indian summer monsoon. Instead, it was found that regional mountain‐valley winds between the Himalayas and South Asia transported polluted air masses toward the TP, especially in the afternoon when regional valley wind are expected to be the strongest and the boundary layer in South Asia is deepest. Additionally, daytime local valley wind further elevated these aerosols to higher altitudes on the TP. This paper provides insights into the transport mechanisms of aerosols from South Asia to the TP. These findings are of great importance since aerosols exhibit significant diurnal variations in the TP region. Plain Language Summary: Previous studies focused on the analysis of the physical or chemical properties of aerosols on the Tibetan Plateau, but this study provides a comprehensive examination of both. The findings reveal that aerosols on the southern slope of the Tibetan Plateau exhibit strong absorption efficiency. Aerosol single‐scattering albedo was low (0.73 ± 0.11 at 550 nm), which may be attributed to aerosol secondary generation and coating. Finally, the mechanism of pollutant transport from South Asia to the Tibetan Plateau was analyzed relies on site observations, satellite, and reanalysis data to highlight the link between diurnal variations of pollutants and transport mechanism. The specific transport mechanism be understood uniformly across different scales, including Indian summer monsoon, regional mountain‐valley winds between the Himalayas and South Asia, and local mountain‐valley winds circulation. Key Points: Aerosol single‐scattering albedo was low (0.73 ± 0.11 at 550 nm) and secondary organic matter was the major aerosol componentThe evolution of aerosols was mainly characterized by diurnal variation that was related to transport mechanism over YadongThe Himalayas‐South Asia regional mountain‐valley winds combined with local mountain‐valley winds transport aerosols to the Tibetan Plateau [ABSTRACT FROM AUTHOR]

The surface air temperature (SAT) trend on the Tibetan Plateau (TP) was 3.45°C 100 years−1 from 1961 to 2014. The multi‐model ensemble (MME) of 33 coupled models participated in the Coupled Model Intercomparison Project phase six (CMIP6) was about 1°C 100 years−1 lower than the observation. Although MME generally shows better skill in reproducing the distribution of SAT trend over TP than most of the CMIP6 models, its performance is greatly degraded by a small group of models, about 12% on average, with large biases. In this paper, the constrained multi‐model ensemble (CMME) based on a certain observation‐based threshold is used to constrain future projections of the SAT trend over TP. Compared with the MME results, the improvements in CMME are mainly over the eastern plateau in historical simulation and are relative to the reduction of the model biases to carbon dioxide (CO2) forcing. Under the high‐emission SSP5‐8.5 scenario, SAT increases significantly over the entire TP. The constraint of CMME on the MME is mainly over the eastern plateau with a difference of 0.5°C 100 years−1, about 6% of the MME results. Under the intermediate‐emission scenario SSP2‐4.5, the effect of CMME is relatively smaller, but the corresponding spatial distribution is similar to that under the SSP5‐8.5 scenario. The CMIP6 models tend to underestimate the warming trend projections over the water source regions in the northeastern plateau and should be noticed. Key Points: The Coupled Model Intercomparison Project phase six model ensemble in surface air temperature trend reproduction on the Tibetan Plateau are greatly degraded by a small group of models with large biasesThe impact of constrained ensemble (CMME) is mainly over the eastern plateau in relative to the reduction of model biases to CO2 forcingThe CMME results indicate the underestimated warming projections in multi‐model ensemble over the northeastern plateau [ABSTRACT FROM AUTHOR]

Information on decadal temperature variations over the northwestern Tibetan Plateau (TP) is still very limited due to a lack of long‐term instrumental data. In this paper, we present a 489‐year (1524–2012 A.D.) reconstruction of annual mean temperature for the northwestern TP using the δ18O record of a 58.82 meter‐long shallow ice core retrieved on the Chongce ice cap in the western Kunlun Mountains. The reconstructed temperature exhibits significant decadal variations, which were mainly driven by the Atlantic Multidecadal Variability. Decadal temperature variation during the Little Ice Age (LIA) is significantly larger than that during the post‐industrial warming period, possibly due to such external forcing as large fluctuations of solar activity and frequent major volcanic eruptions during the LIA. In addition, our reconstruction shows that the recent warming since the 1980s is moderate, comparable to an earlier warm interval in the mid‐20th century, which may partly explain the relatively stable status of glaciers in this region since 1970s. Key Points: The Atlantic Multidecadal Variability plays a critical role in the decadal temperature variations over the northwestern Tibetan PlateauLarge temperature variations before the 1850s were associated with the external forcings, including solar activities and volcanic eruptionsThe weak warming over the northwestern Tibetan Plateau since the 1980s have contributed to the "Karakoram Anomaly" [ABSTRACT FROM AUTHOR]

A large portion of lakes on the Tibetan Plateau (TP) have experienced considerable expansion in the past decades. However, how the lake surface area expansion has influenced regional precipitation, especially its underlying mechanism, has not been investigated. By selecting the most dramatically expanded lake on the TP as a case study, this paper investigates the magnitude and extent of the precipitation response to lake expansion and its underlying mechanism using twin Weather Research and Forecasting (WRF) simulations with and without lake expansion. The results show that the precipitation response to the lake expansion exhibits pronounced spatial and seasonal variations and is generally more intense in the downwind direction than in the upwind direction. During the wet season (the South Asian summer monsoon, SASM), precipitation decreases in the downwind area by −25% ± 16% and −13% ± 15% in the 0–50 km and 50–100 km intervals (from the lake's center), respectively. Conversely, the precipitation increases in the downwind area during the dry season (before the freeze and after the SASM) by 27% ± 36% in the 0–50 km interval. The thermal and evaporative effects, which are generated by lake expansion and propagate in the downwind direction, are the key factors responsible for the precipitation changes. The cooling effect, which generally occurs in the daytime, stabilizes the atmosphere and triggers downward motion, consequently inhibiting precipitation. The warming effect has the opposite effect, and the additional water vapor strengthens this process. However, the effects vary with the seasons, causing seasonal variations in the precipitation response. Plain Language Summary: A large portion of lakes on the Tibetan Plateau have experienced considerable expansion in the past decades. This study aims to assess the regional precipitation response to the expansion of a large lake Seling Co on the Tibetan Plateau and its underlying mechanisms. The results show that the precipitation response to the lake expansion exhibits pronounced spatial and seasonal variations and is generally more intense in the downwind direction than in the upwind direction. The expanded lake tends to inhibit precipitation in the wet season and promote it in the dry season. These findings suggest more attention need to be paid to the areas located downwind of these expanded lakes and an urgent need to improve the understanding of the climate response to the imbalance of the Tibetan Plateau. Key Points: Precipitation response to the expansion of Seling Co on the Tibetan Plateau exhibits pronounced spatial and seasonal variationsThe precipitation response is generally more intense in the downwind directionThe thermal and evaporative effects of the expanded lake dominate the precipitation response [ABSTRACT FROM AUTHOR]

In this paper, three parameterization schemes, one considering gravel influence (test1), one considering organic carbon influence (test2), and one comprehensively considering gravel and organic carbon influence (test3), were set up to modify different typical underlying surfaces of the Tibetan Plateau (TP). In addition, their soil thermal properties and hydraulic property variations were discussed. Additionally, discussing the key thermal and hydraulic parameters affected the performance of different schemes from the perspective of observation data in the TP to improve the simulation ability of soil temperature and soil moisture in the plateau areas. Compared the original Community Land Model (CLM) scheme, test1 resulted in higher soil temperature and lower soil moisture, while test2 had lower soil temperature and higher soil moisture. The key thermal and hydraulic parameters are the changes in the saturated thermal conductivity and the thermal conductivity of dry soil and the variations of the porosity and exponent B, respectively. The test3 scheme was the same as test2 for the modified changes of thermal properties, except that the proportion of change was slightly different. In terms of soil thermal properties, test2 and test3 were better at 0–20 cm depth, while test1 and test3 were better for the deeper (40 cm) simulation. Regarding hydraulic properties, the test1 and test3 schemes performed better on the Gobi and alpine meadows at 20–40 cm depth, while the original CLM scheme and test2 performed better on the underlying grassland surface. Test3 was better at balancing the relationship between the thermal and hydraulic parameters and could be used for the further research on the entire plateau area. Key Points: According to the observation data, the CLM5.0 thermal and hydrological parameterization schemes are modified in this paperThe new scheme is better at balancing the relationship between the thermal and hydraulic parametersThe modified CLM5.0 improves the ability to simulate soil temperature and moisture on the plateau [ABSTRACT FROM AUTHOR]

Snow cover in mountainous terrain plays an important role in regional and global water and energy balances, climate change, and ecosystems. Blowing snow is a frequent and important weather phenomenon over the Tibetan Plateau (TP); however, this process is neglected in most current land surface models, despite the consequential role it plays in the land surface and atmospheric water and energy budgets. In this paper, we present a blowing snow model PIEKTUK coupled with the Community Land Model (CLM4.5) to provide a better estimate of the snow dynamics for the consideration of snow redistribution induced by wind. Two simulations with a 0.065° spatial resolution were performed in 2010 over the TP, namely, a sensitivity experiment with the inclusion of blowing snow effects (CLM_BS) and a control run with the original model (CLM). A specific objective of this study was to evaluate the improvements in the simulations of snow dynamics and other key variables in surface energy partitioning provided by the coupled model, such as the surface albedo and land surface temperature (LST). Compared with a variety of remote‐sensing observations, the results show that the surface snow cover, snow depth, and surface albedo can be better reproduced in most of the TP region by CLM_BS than by the original CLM, particularly in the Kunlun Mountains, Hoh Xil area, and the southwestern TP. In areas with reduced bias, variations in the monthly mean snow cover fraction can be reflected particularly well by CLM_BS. For LST, however, a significant decrease in the nighttime LST bias was detected in CLM_BS, while the bias in the daytime LST increases. The results show considerable potential for the inclusion of the blowing snow process to promote the modeling of snow dynamics and land‐atmosphere interactions on the TP. Key Points: The PIEKTUK blowing snow model was coupled to the Community Land Model to better estimate the snow dynamics over the Tibetan PlateauSnow cover, snow depth, and surface albedo can be better represented by the coupled model with the inclusion of blowing snow effectsA remarkable decrease of bias in the nighttime land surface temperature is detected in the coupled model simulation [ABSTRACT FROM AUTHOR]

This study investigates the relationship between transient luminous events (TLEs) and lightning strokes, and the characteristics of TLE‐producing thunderstorms over the Tibetan Plateau (TP), and compares them to those over the Yangtze‐River Delta (YRD) and East China Sea (ECS) where at the same latitude during 2005–2015. The data were collected using the Imager of Sprites and Upper Atmospheric Lightning (ISUAL) and the World Wide Lightning Location Network (WWLLN) observations. Elves, sprites and halo (abbreviated as ESHs) were dominantly detected over the southeastern TP (∼88%), mostly in August and September (∼81%). Different from the southeastern TP, the detected sprites and sprite‐to‐lightning stroke ratios over the YRD were larger in spring than those in summer and autumn. Halos were frequently observed in August over all study regions. Blue jets were only detected over the YRD. The density of TLEs over the southeastern TP was three times smaller than those over the YRD and ECS, while the density of elves over the southeastern TP was slightly larger than that over the YRD. The average energy of TLE‐related lightning strokes based on WWLLN was found to be larger over the southeastern TP compared to the YRD and ECS. The ESH‐producing clouds over the southeastern TP had a larger scale with a lower lightning frequency than those over the YRD. Plain Language Summary: Transient luminous events (TLEs) are short‐lived electrical discharge that occur in the upper atmosphere. They are generally associated with thunderstorms and are thought to be caused by the lightning within the troposphere. Despite the Tibetan Plateau (TP) being known for having weaker storms and less intense lightning, it is interesting to explore the occurrences of TLEs over this region. Additionally, it is worth investigating the distribution of TLEs, their relationship to lightning strokes, and the characteristics of TLE‐producing thunderstorms. Using the satellite and ground‐based observations, it was found that in the southeastern TP, elves, sprites, and halos (types of TLEs, abbreviated as ESHs) mostly happened in August and September during 2005–2015. The density of TLEs over the southeastern TP was lower than those over the Yangtze‐River Delta (YRD) and the East China Sea (ECS), while the density of elves over the southeastern TP was slightly larger than that over the YRD. The average energy of TLE‐related lightning strokes was larger over the southeastern TP compared to the YRD and ECS. The ESH‐producing clouds over the southeastern TP had a larger scale with a lower lightning frequency than those over the YRD. Key Points: Elves, sprites, and halo (ESHs) occurred mostly over the southeastern Tibetan Plateau (TP) dominantly in August and SeptemberThe average energy of ESH‐related lightning strokes over the southeastern TP was larger than those over the comparison regionsLarger clouds with lower lightning frequency related to ESHs were found over the southeastern TP compared to the comparison regions [ABSTRACT FROM AUTHOR]

Balloon sounding with the Compact Optical Backscatter Aerosol Detector (COBALD) and Frost Point hygrometers (FPs) provides in situ data for a better understanding of the vertical distribution of cirrus clouds. In this study, eight summer balloon‐borne measurements in Kunming (2012, 2014, 2015, and 2017) and Lhasa (2013, 2016, 2018, and 2020) over the Tibetan Plateau were used to show the distribution characteristics of cirrus clouds. Differences of cirrus occurrence were compared by different indices: the backscatter ratio (BSR) at a 455 nm/940 nm wavelength (BSR455 > 1.2/BSR940 > 2), the color index (CI > 7), and the relative humidity with respect to ice (RHice > 70%). Analysis of the profiles indicated that BSR455 > 1.2 was the optimal criterion to identify the cirrus layer and depict the distribution of the CI and RHice within cirrus clouds. The results showed that the median CI (RHice) within the cirrus clouds at both sites was mostly in the 18–20 (90%–110%) range at pressures below 120 hPa. Furthermore, the balloon‐borne measurements combined with Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) measurements indicated a high frequency of cirrus occurrence near the tropopause in Kunming and Lhasa. The top height of cirrus occurrence at both sites was above the cold point tropopause and the lapse rate tropopause. Both Kunming and Lhasa had the highest frequency of thin cirrus clouds in the 0–0.4 km vertical cirrus thickness range. Plain Language Summary: Balloon‐borne measurements of cirrus clouds are scarce over the Tibetan Plateau. The sounding water vapor, ozone, and particles (SWOP) campaign has collected Compact Optical Backscatter Aerosol Detector (COBALD) and Frost Point Hygrometers (FPs) data for eight summers in Kunming and Lhasa. The backscatter ratio at wavelengths of 455 and 940 nm (BSR455, BSR940) from COBALD, the color index (CI), and the relative humidity over ice (RHice) from the FPs are able to indicate the occurrence of cirrus clouds. BSR455 >1.2/BSR940 > 2 was the optimal criterion to identify the cirrus layer in the upper troposphere over the Tibetan Plateau. The results showed that the CI and RHice within the cirrus clouds at both sites have a consistent distribution. The median CI (RHice) remained essentially in the range of 18–20 (90%–110%) below 120 hPa. The top height of cirrus occurrence at both sites was above the cold point tropopause and the lapse rate tropopause. Thin cirrus clouds (less than 400 m thick) had the highest frequency in both Kunming and Lhasa. Key Points: A backscatter ratio over 1.2/2 at a 455 nm/940 nm wavelength can effectively identify cirrus clouds over the Tibetan PlateauCirrus clouds were observed above the cold point tropopause (CPT) in both Kunming and LhasaAbout 38% (39%) of the cirrus clouds are thinner than 400 m in Kunming (Lhasa) [ABSTRACT FROM AUTHOR]

Using various observations and a chemistry‐climate model, this study investigates the impact of the Indian Ocean sea surface temperature (SST) on the wintertime total column ozone (TCO) over the Tibetan Plateau (TP). Our analysis reveals that increases in TCO over the TP are accompanied by anomalously high Indian Ocean SSTs, and vice versa. Further analysis reveals that high Indian Ocean SSTs are accompanied by a narrowing of the northern branch of the Hadley cell, and consequently, the subtropical westerly jet in the Northern Hemisphere (NH) tends to shift southward. The southward shift of subtropical westerly jet can lead to a descent of tropopause and higher lower‐stratospheric temperatures over the TP. The latter causes a descent of isentropic surfaces in the upper troposphere and lower stratosphere. Rossby waves triggered by diabatic heating in the upper troposphere over the Indian Ocean can also lead to a descent of isentropic surfaces over the TP. On the other hand, local descending motions over the TP caused by the Gill Pattern circulation and enhanced Brewer‐Dobson circulation bring ozone‐rich air in the lower stratosphere downward. The descent of tropopause and isentropic surfaces and the downward transport of ozone lead to a downward shift of ozone profiles, and consequently, TCO increases over the TP. Based on multiple linear regression analysis, during 1996–2020 the Indian Ocean SST increase and the equivalent effective stratospheric chlorine decline dominate the wintertime TCO increase over the TP, which is partly offset by the TCO decline due to the TP warming. Plain Language Summary: This study investigates the impact of the Indian Ocean sea surface temperature (SST) on the wintertime total column ozone (TCO) over the Tibetan Plateau (TP) and reveals that increases in TCO over the TP are accompanied by anomalously high Indian Ocean SSTs, and vice versa. The high Indian Ocean SSTs can lead to a narrowing of the northern branch of the Hadley cell, and consequently, a southward shift of the subtropical westerly jet in the Northern Hemisphere (NH). The southward shift of subtropical westerly jet leads to a descent of tropopause and isentropic surfaces in the upper troposphere and lower stratosphere. Rossby waves triggered by diabatic heating over the Indian Ocean also lead to a descent of isentropic surfaces over the TP. In addition, local descending motions over the TP caused by the Gill Pattern circulation and enhanced Brewer‐Dobson circulation bring lower‐stratospheric ozone‐rich air downward. The descent of tropopause and isentropic surfaces and the downward transport of ozone lead to a downward shift of ozone profiles, and consequently, TCO increases over the TP. Based on multiple linear regression analysis, during 1996–2020 the Indian Ocean SST increase has a contribution of 45% to wintertime TCO increase over the TP. Key Points: Wintertime total column ozone (TCO) over the Tibetan Plateau (TP) and sea surface temperature in the Indian Ocean are correlatedThe Indian Ocean SST changes cause a vertical shift of ozone vertical profiles over the TP and then wintertime TCO variationsDuring 1996–2020, the Indian Ocean SST variation has a contribution of 45% to the increasing trend of wintertime TCO over the TP [ABSTRACT FROM AUTHOR]

The calculation of surface sensible heat (SH) and latent heat (LE) fluxes using the bulk transfer models for complex terrains, tall vegetation regions, and morning and evening transition periods remains a challenging problem in numerical weather and climate models. The maximum entropy production (MEP) model, a new method of calculating surface heat fluxes, is coupled with the Noah land surface model (LSM) in the Weather Research and Forecasting (WRF) model. Surface heat fluxes and meteorological variables including air temperature, relative humidity, soil temperature, and precipitation data at nine intensive observation stations and 453 routine meteorological operational observation stations in the Tibetan Plateau (TP) from 1 June to 31 August 2015 are used to evaluate the coupled model. The results show that the MEP method improves the nonclosure of the surface energy balance in the WRF (with an energy residual from 24.3 to 1.9 W m−2), reducing the overestimations of SH and LE and the underestimation of the surface ground heat flux over the complex terrain of TP (with the bias decreases of 50.6% and 117.1% for SH and LE in turn), especially during the daytime. The improved SH and LE reduce the cold and wet biases in the TP by 29.4% and 51.7%, respectively. The MEP model also reduces the overestimated soil temperature by 63%. Moreover, the overestimated daily precipitation is reduced by 3% over the TP. The successful application of the MEP method demonstrates its advantage over the bulk transfer method, providing a new approach for reducing the overestimation of surface heat fluxes and wet and cold biases in numerical forecast models in complex terrains. Plain Language Summary: In this study, the maximum entropy production (MEP) model, as a new promising method of calculating surface heat fluxes, is coupled to the Weather Research and Forecasting Noah land surface model to replace the original bulk transfer model. The coupled MEP model improves the predictions of surface sensible and latent heat fluxes, air temperature and humidity, precipitation, and soil temperature when compared to observations in the Tibetan Plateau (TP) and the adjacent areas. Overall, the coupled MEP model overcomes some drawbacks of modeling surface heat fluxes with bulk transfer models in numerical forecast models and improves the understanding of land‐atmosphere interactions in the TP and their impacts. Key Points: We use the maximum entropy production (MEP) method instead of the bulk transfer method to calculate surface heat fluxes in the Weather Research and Forecasting (WRF) Noah land surface modelThe MEP method improves the nonclosure of the surface energy budget in the WRF, reducing the overestimation of sensible heat and latent heat over the Tibetan Plateau (TP)The MEP method reduces the cold and wet biases around the TP, leading to an improved understanding of land‐atmosphere interactions [ABSTRACT FROM AUTHOR]

Understanding the runoff response to climate change in the Tibetan Plateau (TP) is critical to water resources management since TP is the "Water Tower of Asia" and is sensitive to climate change. However, previous studies have paid more attention to the changes in annual and monthly runoff. Therefore, the changes in the characteristics of floods and droughts are still unknown, particularly in the Yarlung Zangbo River basin (YRB) in the southern TP. Therefore, this study simulates the runoff in four subbasins in the YRB using the GR4J_SNOW model to depict the characteristics (including frequency, severity, peak, and duration) of floods on a daily scale and those of droughts on a monthly scale. It is done in historical (1979–2014) and future (2049–2084) periods under different climate scenarios (RCP4.5 and RCP8.5), and then the changes in floods and droughts between the two periods are comprehensively compared. The results indicate that the YRB has experienced marginal streamflow change during the historical period. Under future varying climate change scenarios, however, the YRB might become wetter with increasing frequency, volume, and peak of floods, along with decreasing frequency, severity, and duration of droughts. In the upstream YRB, covered by more snow with a drier climate, the flood and drought characteristics appear to be more sensitive to climate change than in the downstream YRB. This study is helpful for a better understanding of the hydrological process in the TP under climate change and for forming sustainable water resource strategies for the surrounding regions of the TP. Plain Language Summary: The Tibetan Plateau (TP) is the Asian water tower, providing water resources to hundreds of millions of people living downstream. The Yarlung Zangbo River basin (YRB), located in the southern part of the TP, has attracted increasing attention because most of the Tibetan people live there and it is the upper stream of the Brahmaputra River. It is not clear how floods and droughts, the two most serious natural disasters, could change under climate change in the YRB. This study simulates the changes in flood and drought characteristics in the YRB in the historical (1979–2014) and future (2049–2084) periods under different climate scenarios (RCP4.5 and RCP8.5). Our results show that the YRB could become wetter with increasing floods and mitigated droughts in the future, despite minor changes in flood and drought characteristics in the historical period. The change could be stronger upstream than downstream. This study can be helpful for long‐term water resource management and planning on the TP. Key Points: The characteristics of floods and droughts in the Yarlung Zangbo River basin (YRB) are comprehensively analyzed in the past and futureThe YRB is expected to become wetter in the future, reflected by increased floods and alleviated droughtsThe flood and drought characteristics in its drier upstream are more sensitive to climate change than those in the humid downstream [ABSTRACT FROM AUTHOR]

Using Modern‐Era Retrospective analysis for Research and Applications Version‐2 (MERRA‐2) re‐analyses, we have examined recent trends (2000–2019) in transport of surface carbonaceous aerosols (CAs), that is, organic carbon and black carbon, to the upper troposphere and lower stratosphere (UTLS) during the Asian summer monsoon (ASM). We find a significant increased concentration of UTLS CA, linked to a linear trend in an expansion of the Asian Summer Monsoon Anticyclone (ASMA). Over core monsoon latitudes (25°–35°N), the trends in UTLS CA are enabled by increased upward transport from surface sources via an intensified monsoon meridional circulation, with increased latent heating over the southern Tibetan Plateau and foothill regions, enhanced by feedback processes associated with radiative heating by UTLS CA. In the extra‐tropics, increased UTLS CA stems primarily from an extended source of increased wildfire emissions over eastern Siberia and northern Asia, coincident with a large‐scale anomalous anticyclone with enhanced surface warming and drying near (80°–120°E, 55°–70°N). Here, CAs are transported upward from the surface to the ULS, likely by increased pyro‐convection associated with enhanced wildfires, and enter the tropical UTLS via increased equatorward transport on the eastern flanks of anomalous upper‐level anticyclones, coupled to the expanded ASMA. Overall, the increasing UTLS CA trends associated with expansion of the ASMA are consistent with a hydrostatic expansion of a warming troposphere, reflected in a rise in the tropical tropopause and consequential dynamical adjustments of the ASM subtropical jetstream, modulating the climate of the greater ASM region. Key Points: An interdecadal trend (2000–2019) in an expansion of the Asian Summer Monsoon Anticyclone (ASMA) is foundExpansion of the ASMA facilitates surface‐to‐upper troposphere and lower stratosphere transport of carbonaceous aerosols over the Asian monsoon regionsResults are consistent with a rise of the tropopause due to the hydrostatic thermal expansion of the troposphere in a warming climate [ABSTRACT FROM AUTHOR]

The interdecadal changes in the dominant mode of the summer precipitation over the central‐eastern Tibetan Plateau (TP) are investigated around the mid‐1990s. It is found that the leading empirical orthogonal function mode of the interannual variations of summer precipitation over the central‐eastern TP is shown an out‐of‐phase pattern, with opposite variation between the southeastern and northeastern TP during 1961–1996, while the dominant mode become an in‐phase pattern during 1997–2019. During 1961–1996, the dipole pattern of TP precipitation is mainly related to the North Atlantic Oscillation (NAO) and associated circulation anomalies. However, the impact of NAO on the dipole pattern of TP precipitation has weakened since the mid‐1990s. In contrast, during 1997–2019, more pronounced positive height anomalies in the upper troposphere are observed over the whole TP regions. Meanwhile, the southerly moisture flux from the Bay of Bengal and the Philippine Sea is prevalent significantly with strong moisture convergence. Further analysis demonstrates that this interdecadal spatial change is mainly linked to the significant increasing of the sea surface temperature in the North Atlantic, South Atlantic, and Indo‐Pacific warm pool, via wave trains propagation. The wave train‐related positive height anomalies over the TP regions are in favor of the strengthening of the South Asian high (SAH). Moreover, the zonal and meridional mean temperature advections by SAH‐related circulation anomalies are primarily responsible for the intense vertical flow anomalies. Consequently, the summer precipitation anomalies over the entire TP regions are largely enhanced and formed the mono‐sign pattern during 1997–2019. Key Points: The dominant mode of precipitation in central‐eastern Tibetan Plateau (TP) changes from a dipole pattern to mono‐sign pattern in mid‐1990sThe change in the TP precipitation pattern is linked to the increasing of sea surface temperature anomalies in the Atlantic Ocean and Indo‐Pacific warm poolThe circulation anomalies related to the strengthening of South Asian high mainly contribute to the mono‐sign pattern of TP precipitation [ABSTRACT FROM AUTHOR]

This study evaluates the simulation of the seasonal cycle of water isotopic composition over Tibetan Plateau regions (TP) from six isotope‐enabled general circulation models (GCMs) participating in the second Phase of Stable Water Isotope Intercomparison Group. For both meteorological factors (precipitation rate and wind field) and isotopic composition, GCMs generally agree with reanalysis data and in‐situ observations, but there is a significant spread across models and the isotopic seasonality is systematically underestimated. In the southern TP, the precipitation isotopic composition is more depleted in summer than in winter, and the amplitude of the simulated isotopic seasonal variations is primarily driven by the amplitude of the simulated upstream precipitation. In contrast, in the northern TP, the precipitation isotopic composition is more depleted in winter than in summer, and the amplitude of the simulated seasonal variability of isotopes is mainly driven by the simulated strength of the zonal wind. We conclude that the skill of a GCM to simulate the seasonal cycle in the isotopic composition depends mainly on the skill of the GCM to simulate the Indian summer monsoon precipitation and the westerlies. The same causes contributing to the underestimated seasonality at present‐day may also contribute to the underestimated δ18O change at the mid‐Holocene. Plain Language Summary: The stable isotopic composition of water is determined by the relative abundances of heavier to lighter isotopologues. Isotope‐enabled general circulation models (GCMs) simulate water isotope composition considering several physical processes operating in the hydrologic cycle. Therefore, a comparison between observed and simulated values provides a better understanding of the processes constraining the isotope values. However, the simulated water isotopic composition is sensitive to various physical processes and parameterization schemes. In this study, we investigate how the model biases in the representation of atmospheric processes affect the simulation of isotopic composition over the Tibetan Plateau (TP). We compare the simulated isotopic composition in precipitation and water vapor to in‐situ and satellite measurements. Our analysis indicates that most GCMs underestimate the seasonality of the isotopic composition in the precipitation and vapor. In the southern TP, the spread of upstream precipitation is an important factor controlling the inter‐model spread in isotopic seasonality. In the northern TP, the westerlies majorly control isotope biases. Key Points: Models systematically underestimate the precipitation isotopic seasonality both in the southern and northern TPThe inter‐model spread of precipitation isotopic seasonality in the southern TP is driven by the spread of upstream precipitationThe westerlies dominate the inter‐model spread of precipitation isotopic seasonality in the northern TP [ABSTRACT FROM AUTHOR]

High‐temporal‐resolution geostationary satellite infrared measurements are always used to capture and predict typical characteristics at the cloud top of rapidly developing strong storms at the pre‐convection or convection initiation (CI) stage. However, the large false alarm rate of CI nowcasting is difficult to avoid due to the complex and unpredictable trigger factors. Although the microwave measurement technique can observe thick clouds and even the precipitation within clouds due to the weaker atmospheric extinction effect on microwave, microwave data from polar‐orbiting satellites are rarely used to observe the CI due to their relatively low temporal resolution. In this study, we analyze several previously unknown CI characteristics over the East Asia region from 2016 to 2019 based on spatially and temporally matched Advanced Technology Microwave Sounder data. These typical CI samples are initially identified by using continuous infrared images from the Himawari‐8 geostationary satellite. The results show that there is a distinct cloud optical depth at the pre‐convection stage in the western (deep cloud clusters) and eastern (shallow cloud clusters) Tibetan Plateau (TP). The shallow precipitating cloud clusters of the CI over the eastern TP are possibly attributed to the favorable local dynamic and thermal conditions stem from the Asian monsoon. Another notable finding shows that the fast‐developing CI over the ocean has thick clouds compared with the samples over the land. Overall, the unique CI characteristics found from microwave observations in this study indicate that the future geostationary microwave sounder technologies will almost certainly provide some new findings and enhance early warning capabilities about convection. Key Points: This study uses microwave sounder data to explore some previously unknown convection initiation (CI) characteristicsMore relatively shallow cloud clusters at the pre‐convection stage are found based on microwave observations in the eastern Tibetan PlateauCompared with the samples over the land, strong CI that develops rapidly over the ocean has thicker clouds [ABSTRACT FROM AUTHOR]

The dependence of the feedback signal on atmospheric conditions is still poorly understood and may lead to an underestimation of feedback strength due to opposite responses of precipitation to soil moisture. Based on data from observation stations on the Tibetan Plateau and from satellites, this study evaluated the response of convective clouds to the change of evaporation fraction (EF) and analyzed how surface conditions affect the initiation and development of convection in different coupling regimes. After considering coupling regimes classified by the tropospheric state, the afternoon convective cloud showed a strong response to EF, which is negative feedback in the dry coupling regime and positive feedback in the wet coupling regime. Organized deep convection defined by both the cloud properties and the afternoon precipitation displayed this phenomenon. This shows that the lack of a strong response of convection to EF is due to the dependence of this response on the coupling regime, rather than on the method of defining convection. We also found that the difference in surface heat flux between the two regimes is more significant in the afternoon, while the difference of meteorological elements is most significant before noon. These results provide support for the use of ground‐based meteorological data to determine coupling regimes. We also used a regression tree to decompose the effects of coupling regimes and EF into basic near‐surface meteorological elements, the results of which provide support for some of our conclusions. Key Points: Considering coupling regimes classified by the tropospheric condition, the convection showed a strong response to evaporation fraction (EF)Two convection definitions, depending on cloud properties and afternoon rainfall, showed regime‐dependent responses to EFIt is possible to determine the regime without profiles, surface meteorological elements are significantly different in the morning [ABSTRACT FROM AUTHOR]

The alpine lakes widely distributed over the Tibetan Plateau (TP) are not only highly sensitive to climate but also regulate the regional climate. However, the lack of TP alpine lake observations limits the understanding of the lake‐atmosphere interactions. Here, we show the relative importance of parameterizing lake surface and internal thermal processes in describing the lake energy budget and lake‐atmosphere interactions. Based on the in situ observations at Lake Nam Co, a large and deep lake in the TP, we employed the coupled Weather Research and Forecasting with lake (WRF‐Lake) model to clarify their relative roles. Results show that the original model produces cold biases and too early timing of lake freeze onset. The adjustments of parameterizations of lake internal (temperature of maximum water density, extinction coefficient) and lake surface (roughness length) processes significantly improve the ability of the WRF‐Lake in simulating the lake thermal features and the freeze onset timing. The different parameterizations of lake internal thermal processes affect the onset timing of lake freeze mainly by altering the release of turbulent heat fluxes in summer, but the adjustments of lake surface roughness lengths change the turbulent heat fluxes during the unfrozen season from summer through early winter. Accordingly, the simulated lake freeze onset is much more sensitive to the surface roughness length schemes than to the internal thermal processes schemes. As the lake‐atmosphere interactions are very sensitive to the lake freeze onset, our results are critical for understanding and simulating the impact of TP lakes on the regional climate. Key Points: Simulated lake temperature profile and freeze onset timing are closer to observations with improved parameterizations in coupled Weather Research and Forecasting with lakeCompared to the lake internal thermal processes, the surface roughness length scheme (ROU) is the key to control lake freeze onset timingAdjustments of lake surface ROU notably delay the freeze onset by reducing turbulent heat fluxes during unfrozen season [ABSTRACT FROM AUTHOR]

The surface heating on the Tibetan Plateau (TP) exerts large influence on the Asian summer monsoon. Drivers of TP surface heat include the tropical forcings and other climate modes in middle and high latitude of the Northern Hemisphere, however whether the climate modes in Southern Hemisphere influence the TP surface heat is rarely studied. Using multiple source data diagnosis and numerical experiment from an atmospheric general circulation model (AGCM), we found that the Antarctic Oscillation (AAO) in May can efficiently modulate the subsequent surface heat source over the TP in June. When the AAO is in positive phases, a northeastward propagating atmospheric Rossby wave train originates from the Amundsen Sea low. As a part of this wave train, a pair of anomalous cyclone and anticyclone in the Southern Hemisphere accelerates the surface southeasterlies between them, accompanied by cold sea surface temperature (SST) anomaly in the equatorial middle and eastern Indian Ocean induced by the wind‐evaporation‐SST feedback. Due to the large thermal inertia, in June, the cold SST anomaly stimulates anticyclone anomalies over the western TP and eastern Arabian Sea, which increase the moisture transportation toward the TP and are conducive to the formation and maintenance of the precipitation over the middle and eastern TP. In contrast, the surface heat source, which is dominated by the upward sensible heat flux, is reduced substantially. This result indicates that the AAO can be one of the precursors of the TP heat source, and may help improve the prediction of the Asian summer monsoon. Plain Language Summary: The surface heating of the Tibetan Plateau (TP) has vital impacts on the Asian monsoon, and people's production and life. However, previous studies have mainly focused on the study of the Northern Hemisphere, and less attention has been paid to whether and how the Southern Hemisphere signals can affect the surface heating of the TP. Through numerical simulations and various data diagnostic studies, we show that the air pressure anomaly around the Antarctic (Antarctic Oscillation; AAO) in May can effectively regulate the surface heat source over the TP in June. During the positive phase of the AAO, an atmospheric wave train propagates from the Amundsen Sea to the Indian Ocean. Due to the anomalous surface wind, the wind‐evaporation‐SST feedback has been enhanced, resulting in the cold SST anomaly in the equatorial Indian Ocean. Owing to the large thermal inertia of the ocean, the cold SST anomaly lasts until June. The anticyclone anomalies in the western TP and the eastern Arabian Sea are stimulated, which are conducive to the transport of water vapor over the TP and induce the abnormal precipitation over the TP, while the surface sensible heat flux is greatly weakened, which affects the surface heating of the TP. Key Points: A robust linkage exists between the Tibetan Plateau (TP) surface heating and the Antarctic Oscillation (AAO)The AAO influences the Indian Ocean through a Rossby wave trainThe Indian Ocean sea surface temperature prolongs the effect of the AAO and influences the TP surface heating [ABSTRACT FROM AUTHOR]

The Tibetan Plateau (TP), a region with limited human activity, is sensitive to regional and global climate change. In recent decades, surface observations have shown that concentrations of air pollutants (CO, NO2, SO2, and PM2.5) in Lhasa, a city on the TP, are similar to those in regions with high anthropogenic emissions (e.g., Eastern China). This study utilized the WRF‐Chem model and observational datasets to evaluate the concentrations and sources of air pollutants in Lhasa during August 2016. Our results show that the WRF‐Chem model with the standard emission inventory underestimated the surface concentrations of CO, SO2, and PM2.5 in Lhasa from 3 August 2016, 0:00 to 15 August 2016, 23:00 (UTC +8) by 59%, 92%, and 79%, respectively. Sensitivity simulations show that the contribution of long‐range transport of air pollutants from Eastern China and India is less than 10% for Lhasa. Insufficient emissions are found to be the main reason for the model's underestimation of air pollutants in Lhasa. Our study suggests that the emissions of CO, SO2, and PM2.5 in Lhasa in August 2016 might be underestimated by 85%, 93%, and 88%, respectively. Local anthropogenic emissions have a significant impact on urban air quality on the TP and deserve further attention. Plain Language Summary: The Tibetan Plateau (TP), a region with limited human activity, is sensitive to regional and global climate change. In recent decades, surface observations show that concentrations of air pollutants (CO, NO2, SO2, and PM2.5) in Lhasa City on the TP are similar to those in heavily polluted regions (e.g., Eastern China). The regional chemistry transport model (WRF‐Chem) with the standard emission inventory underestimated the surface concentrations of CO, SO2, and PM2.5 in Lhasa in August of 2016 by 59%, 92%, and 79%, respectively. Our study found that the contribution of long‐range transport of air pollutants from Eastern China and India is less than 10% for Lhasa city. Our study suggests that the main reason for the model's underestimation of the air pollutants in Lhasa is insufficient emissions in the standard inventory and the emission of CO, SO2, and PM2.5 in Lhasa in August 2016 might be underestimated by 85%, 93%, and 88%, respectively. Local anthropogenic emissions have a significant impact on urban air quality on the TP and deserve further attention. Key Points: The default model underestimates the concentrations of CO, SO2, and PM2.5 in Lhasa by 59%, 92%, and 79%The current emission inventory may underestimate the emissions of CO, SO2, and PM2.5 in Lhasa by more than 80%Urban air quality on the Tibetan Plateau deserves further attention for air pollution control [ABSTRACT FROM AUTHOR]

The lake surface water temperature (LSWT) on Tibetan Plateau (TP) is sensitive to climate change. Based on a 1‐D lake model, we have investigated the interdecadal variation and long‐term trend of LSWT in Lake Nam Co (LNC) on TP during 1980–2018 and quantified the relative contributions of atmospheric factors to the LSWT trend. Results show LNC was warmed with a rate of 0.29°C decade−1, which is smaller than the warming of ambient air (0.45°C decade−1). The weakened wind speed, rising air temperature, increased downward longwave radiation, and decreased shortwave radiation contributed about 35%, 30%, 20%, and −15% of the estimated long‐term LSWT trend during 1980–2018, respectively. The contribution rate of 32.5% was from the interactions among all forcing variables. The primary warming was completed before 1997 (0.30°C decade−1) and was followed by a hiatus that the LSWT jumped to a warm level with a slightly negative trend (−0.08°C decade−1) after 1997. During this hiatus, the wind speed recovered from decrease and the deceleratingly increased downward longwave radiation slowed down the LNC warming. Particularly, the specific humidity shifted from increasing to decreasing trend played a key role in the hiatus of LNC warming after 1997, despite its slight contribution (−2.5%) to the LSWT trend during 1980–2018. The results showed the particularity of warming for a TP lake compared to the other ice‐covered lakes worldwide and provided a quantitative perspective for understanding the relative contributions of atmospheric factors to the long‐term trend of LSWT. Key Points: As an ice‐covered lake, Lake Nam Co (LNC) warmed with a smaller rate than the local surface air temperature during 1980–2018The interdecadal shift of surface specific humidity played a key role in the hiatus of LNC warming after 1997The individual and cross contributions of different atmospheric factors to the long‐term trend of surface water temperature are quantified [ABSTRACT FROM AUTHOR]

Diurnal variations in clouds and radiation budgets over four subareas of the Tibetan Plateau (TP) during summer (June–August) are analyzed using the Clouds and the Earth's Radiant Energy System (CERES) synoptic 1° (SYN1deg) data from 2000 to 2020. The results show that the total cloud amount decreases from southeast to northwest and is larger during daytime (71.1%) than nighttime (67.2%) over the entire TP. High‐clouds develop in the afternoon, persist during nighttime, and dissipate after sunrise. Low clouds develop after sunrise and dissipate in the afternoon over the entire TP, but show opposite temporal variation over the Kunlun Mountains. The net radiation budget at the top‐of‐atmosphere reaches its maximum at noon. The surface net radiation budget is positive in the daytime and negative at nighttime. These features are mainly adjusted by the cloud distribution. The diurnal variations in heating rate over the four subareas are similar in the upper atmosphere but different in the lower layer. The low‐atmosphere heating rate shows a maximum value over the center‐south (CS) subarea, while it is lowest over the west (W) subarea. Internal cloud forcing has distinct regional differences over the four subareas: it shows a heating effect in the low atmosphere and a cooling effect in the middle atmosphere over the CS subarea, whereas over the W subarea it shows a radiative cooling effect in the low atmosphere and no significant radiative effect in the middle layer. The findings of this study help toward improving our understanding of the TP's energy cycle. Key Points: There are distinct subarea differences in cloud cover diurnal variation over the Tibetan Plateau, especially in the center‐south (CS) and westThe cloud distribution redistributes the vertical and horizontal atmospheric heating rate and internal cloud forcingThe internal cloud forcing in the low layer over the CS subarea has a heating effect, but over the west subarea it has a cooling effect [ABSTRACT FROM AUTHOR]

The hydroclimatology and hydrometeorology of flooding over the Third Pole region is poorly understood, despite its societal and environmental significance. Here we examine extreme rainfall and flooding over the eastern Tibetan Plateau (TP) based on empirical analyses of long‐term, in‐situ rainfall and stream gaging observations as well as the ECMWF Reanalysis fields. We develop a flood catalog that consists of 168 extreme rainfall‐runoff floods over the eastern TP, and characterize the synoptic conditions for flood‐producing storms based on the principal component analysis. We show the transitional pattern form Asian summer monsoons to midlatitude systems as the most frequent synoptic conditions for flooding over the eastern TP. The interplay between complex terrains and moisture transport determines the contrasting flood characteristics (in terms of intensity and spatial pattern) under different synoptic environments. We carry out high‐resolution Weather Research and Forecasting modeling analysis for four flood‐producing storms over the eastern TP. We highlight the interaction of complex terrains and nocturnal low level jets as the key mesoscale ingredients in dictating a pronounced diurnal cycle of extreme rainfall over the southeastern portion of TP. Our results establish the link between large‐scale synoptic environment, mesoscale process, and regional flood hydrology over the eastern TP, and therefore contribute to improved flood risk management practices over the Third Pole region under a changing climate. Key Points: We examine meteorological floods over the eastern Tibetan Plateau based on long‐term, in‐situ stream gaging and rainfall observationsThe transitional pattern from Asian summer monsoons to midlatitude systems is the most frequent synoptic condition for floodingThe interplay between complex terrains and moisture transport dictates contrasting flood characteristics under different synoptic patterns [ABSTRACT FROM AUTHOR]

The Tibetan Plateau (TP) is one of the regions with the most remarkable diurnal variations in the global atmosphere. The zonal shear line (ZSL) is the primary synoptic system inducing precipitation over the TP in boreal summer. It is of great significance in studying its diurnal variation. This study objectively identified and composited 11 ZSL cases inducing anomalous heavy precipitation based on the ERA5 hourly reanalysis datasets from June to August during 1980–2019. The diurnal variation characteristics and mechanisms of ZSL's intensity were explored based on the composited ZSL. Results suggest that the intensity of ZSL has significant diurnal variation, reaching the peak at midnight (about 23 Local Solar Time). The dynamical and thermal structures near the ZSL both show significant diurnal variations. There is a significant heating effect near the ZSL after sunrise, followed by strong divergence (convergence) in the upper (lower) layer and significant increases in water vapor flux convergence and ascending motions. The vorticity is strongest at midnight. Diagnosis by the complete‐form vertical vorticity tendency equation reveals that the thermal effect, dominated by vertically non‐uniform distribution of atmospheric diabatic heating, is the most crucial factor affecting the diurnal variation of ZSL's intensity. The configuration of solar radiation and sensible heat in the near‐ground layer and latent heat in the middle and upper layers jointly dominate the vertically non‐uniform heating. The horizontally non‐uniform heating only contributes little to the local change of vorticity at 500 hPa. Ascending motion and vorticity advection have only weak effects. Key Points: The intensity of ZSL peaks at midnight (about 23 LST), and its dynamical and thermal structures also have significant diurnal variationsThe non‐uniform vertical distribution of atmospheric diabatic heating is the primary mechanism of the diurnal variation of ZSL's intensityThe vertically non‐uniform heating is related to configurations of Q–QLH in the near‐ground layer and QLH ${Q}_{LH}$ in the middle and upper layers [ABSTRACT FROM AUTHOR]

Investigation of the variations of hydrological cycles during the Last Interglacial (130–115 ka; LIG) may deepen our understanding of climate change in a warmer‐than‐present world induced by Earth's orbit. Here we revealed an intensified atmospheric branch of the hydrological cycle over the Tibetan Plateau (TP) in summer during the LIG relative to the preindustrial period, using the mesoscale Weather Research and Forecasting model driven by the Community Earth System Model. Our results showed that precipitation over the TP increased by 5.65 × 107 kg s−1, with 63.2% of the increase contributed by advected moisture transports, and the remaining 36.8% caused by local moisture recycling processes. As for advected moisture transports, the inflow increased by 1.93 × 107 kg s−1 and the outflow decreased by 0.87 × 107 kg s−1, respectively. Variations of the moisture transport were more profound at the eastern and northern edges, which were linked with changes in Indian summer monsoon and westerly jets. Regarding local moisture recycling processes, evaporation enhanced by 2.85 × 107 kg s−1 over the TP, influenced by variations in surface air temperature, surface net radiation flux, surface relative humidity, and surface wind fields. Increased evaporation accompanied by enhanced moisture inflow resulted in an enriched precipitation recycling ratio of ∼1% over the TP during the LIG relative to the preindustrial in summer. Our results aid in understanding the atmospheric branch of the hydrological cycle over the TP in an orbit‐induced warmer world and shed light on the future evolution of the hydrological cycle over the TP at multi‐millennial and orbital timescale. Key Points: Dynamical downscaling simulations for the Last Interglacial from Weather Research and Forecasting driven by Community Earth System ModelIntensified atmospheric branch of the summer hydrological cycle over the Tibetan Plateau during the Last Interglacial (LIG)Intensified hydrological cycle was manifested in both external and internal cycles during the LIG [ABSTRACT FROM AUTHOR]

Investigated in this study are the seasonal and semi‐diurnal variations of the cloud‐phase climatology over the southern Himalayas and adjacent regions by using 5 years of Himawari‐8 cloud‐product data (2016–2020). The four selected regions from south to north are the Gangetic Plains (I), Himalayan foothills (II), southern slope of the Himalayas (III), and the Himalayan–Tibetan Plateau region (IV), respectively. Results showed that the cloud frequency of cloud gradually increases from region I via II to III, then sharply decreases as the altitude increases up to IV. Ice‐phase clouds occurs more frequently over regions I/II (III/IV) during boreal summer (winter), while water‐phase cloud has a higher frequency over region III/IV (I/II) in summer (winter), respectively. All of the different cloud phases have a clear seasonal cycle. Furthermore, the semi‐diurnal variation shows that water‐phase clouds tends to have an occurrence frequency peak around noon (in the later afternoon) over regions I/II/III in summer (winter), whereas over region IV it only occurs more in the morning in both seasons. Ice‐phase cloud generally occurs more in the late afternoon in both boreal summer and winter, especially over region IV. Further analysis showed that the differences in the cloud‐phase characteristics over the southern Himalayas and adjacent regions are likely related to the interactions of the synoptic‐scale circulation, the topography, and the water vapor transport. Plain Language Summary: By using 5 years geostationary weather satellite cloud product, we investigated the seasonal and semi‐diurnal variations of the cloud‐phase climatology characteristics over the southern Himalayas and adjacent regions, including four select sectors of the plain, foothill, slope and plateau. We found that the cloud frequency gradually increases from plain via foothill to slope, then decreases as the terrain increases up to plateau. All different phase clouds have a clear seasonal cycle and semi‐diurnal variations. Such as ice‐phase cloud occurs more over the plain and the foothill during summer season, while it occurs more over the slope region and plateau in winter; water‐phase cloud has a peak at noon (later afternoon) over the plain/foothill/slope in summer (winter), while over the plateau, it only occurs more in the morning. The results are important for comprehend how the southern Himalayas impact regional climate. Key Points: Cloud frequency increases significantly from region I via II to III, then decreases as the elevation further increases up to region IVIce‐phase clouds occurs more frequently over regions I/II (III/IV) in summer (winter), which is opposite to the occurrence of water‐phase cloudWater‐phase clouds tend to occur more around noon (in the later afternoon) over regions I/II/III in summer (winter), while it only occurs more in the morning over region IV [ABSTRACT FROM AUTHOR]

Previous empirical studies have indicated strong influences of autumn and winter Tibetan Plateau (TP) snow cover extent (SCE) anomalies on the winter Pacific‐North American (PNA) and also East Atlantic teleconnection patterns over the North Atlantic and Europe. Our early numerical experiments reproduced an observed wintertime PNA response to an extensive heavy TP snow anomaly. This study further investigates impacts of autumn‐winter TP snow anomalies on North Atlantic‐Europe and Arctic climate. Expressing snow conditions as snow water equivalent (SWE), observational analysis shows that the principal component time series associated with the leading empirical orthogonal function (EOF1) pattern of autumn TP SWE anomalies is significantly correlated to a remote equivalent barotropic tripole structure in winter, which resembles the negative phases of two teleconnections, North Atlantic Oscillation (NAO) at the surface and West Atlantic (WA) in the mid‐troposphere. This indicates that the hydrological effect of TP SWE differs from the albedo effect of TP SCE in snow‐atmosphere teleconnections. Numerical experiments using autumn TP SWE EOF1 and its persistent changes in winter as idealized snow forcing in a coupled atmosphere‐ocean general circulation model simulate a winter negative NAO/WA response over the North Atlantic‐Europe sector and a negative Arctic Oscillation over the Northern Hemisphere similar to observations. The NAO/WA responses result from mechanisms of horizontal propagation of stationary Rossby wave energy and a transient eddy feedback. Results also indicate that heavy TP SWE induces significant Eurasia cooling, and a consistent pattern of Arctic sea ice anomalies, demonstrating widespread Northern Hemispheric impacts of TP snow anomalies. Plain Language Summary: The Tibetan Plateau has an area of 2.5 million square kilometers and an average elevation around 4,000 m, and is often called "the third pole" due to its polar‐like climate in midlatitude Eurasia. Because of the Tibetan Plateau location under the main Northern Hemisphere storm track, persisting unusual weather interacts with the jet stream to cause recurring weather extremes in many distant locations and, in turn, certain unusual weather events elsewhere can influence Tibetan Plateau weather. We focus on widespread Northern Hemispheric effects of the amount of snow over the Tibetan Plateau. For example, heavy autumn Tibetan Plateau snow causes the surface to be unusually cold, which delays snow melt in that area, and also energizes waves in the jet stream. Cold air far south over China is "overcompensated" by a warm air flow over the North Pacific bringing warm weather to North America, then a cold air flow into Europe and western Russia, and a warm air flow into the Middle East and Central Asia. Approximately opposite effects occur with deficient Tibetan Plateau snow. Heavy or deficient autumn snow usually persists through the winter, and knowledge of its worldwide effects can be used to improve seasonal forecasts. Key Points: The main pattern of autumn Tibetan Plateau snow water equivalent anomalies is highly persistent through winterHeavy autumn‐winter Tibetan Plateau snow tends to favor negative North Atlantic Oscillation and West Atlantic teleconnectionsThese snow anomalies favor a cold European winter, a mild North American winter, and consistent Arctic sea ice variations [ABSTRACT FROM AUTHOR]

Raindrop size distribution (DSD) observations with OTT PARSIVEL2 disdrometers at Dari and Delingha in the northeast of the Tibetan Plateau (TP) during summer 2019 and 2020 were utilized to investigate the DSD characteristics and DSD‐based polarimetric radar quantitative precipitation estimation (QPE) relations on the X, Ku, and Ka bands. The DSD characteristics were examined for different rain rates (R) and for stratiform and convective rainfall types. The raindrop spectra became wider and flatter as the R increased. Gamma parameters N0, μ, and λ (representing intercept, shape, and slope parameters, respectively) were smaller for convective compared to stratiform rainfall, corresponding to the broader and flatter convective raindrop spectra. The μ–λ and Dm–log10Nw relationships were also examined in our study. There was a significant μ–λ correlation, with a quadratic function relationship. The summer convective rainfall at both Dari and Delingha showed continental‐like clusters based on the Dm–log10Nw relationship. The DSD‐based two‐parameter polarimetric radar QPE relations (R(Zh, ZDR), R(KDP, ZDR)), and one‐parameter relations (R(Zh), R(KDP)) at the X, Ku, and Ka bands were proposed, and the R computed from DSD was implemented to evaluate these relations. The performance of two‐parameter models was stronger than that of one‐parameter models. Moreover, R(Zh, ZDR) and R(KDP, ZDR) performed better for the X and Ku bands, while the R(KDP, ZDR) model performed best for the Ka band. The ground‐based Ka/Ku band measurement Z at Dari was used to evaluate the Z–R and R−Dm QPE relations. The R−Dm relations had a better performance compared to the Z–R relations. The Ku radar‐derived R series are more consistent with the DSD measured counterparts. The research of the dual‐polarization radar parameter models is vital to develop radar QPE algorithms on the TP. Key Points: The raindrop spectra become wider and flatter as the R increases. Gamma parameters were smaller for convective than for stratiform rainfallThe summer convective rainfall at both Dari and Delingha showed continental‐like clustersThe performance of two‐parameter models (R(Zh, ZDR) and R(KDP, ZDR)) was stronger than that of one‐parameter models (R(Zh) and R(KDP)) [ABSTRACT FROM AUTHOR]

The hydroclimate of the Tibetan Plateau (TP) and Central Asia (CA) plays a crucial role in sustaining surface water reservoirs and thus water resources in the respective regions. In this study, we investigate the changes in Asian hydroclimate and its driving forces during specific time intervals in the last 3 Ma. We conduct high‐resolution (∼0.75° per grid cell) general circulation model ECHAM‐5 experiments with boundary conditions for the mid‐Pliocene (∼3 Ma), the Last Glacial Maximum (LGM; ∼21 ka), the mid‐Holocene (∼6 ka), and the pre‐industrial. Results suggest that seasonally relatively high precipitation rates (>1 mm day−1) were longer in the mid‐Pliocene and shorter in the LGM, relative to the pre‐industrial. We calculate different monsoon indices to detect changes in the intensity, strength and duration of the East Asian summer monsoon (EASM), South Asian summer monsoon (SASM), and the Indian summer monsoon (ISM), and construct climatologies of mid‐latitude high‐level westerly jet (WJ) stream occurrences based on the ECHAM5 wind fields. Our results suggest that in warm periods (e.g., mid‐Pliocene or interglacial), the WJ migrates northward earlier in the year (April) and reaches higher latitudes than in the pre‐industrial, resulting in a wetter TP and CA. During cooler periods (e.g., LGM or glacial), the WJ migrates northward later in the year (June) and remains over lower latitudes, resulting in a drier TP and CA. Increased/decreased local precipitation in TP and CA for the mid‐Pliocene/LGM experiments correlates strongly with (a) intensity, strength and duration of the EASM, SASM, and the ISM and (b) WJ latitudinal position. Key Points: High‐resolution general circulation model (ECHAM5) is used to study past changes in hydroclimate in the Tibetan Plateau and Central AsiaSeasons with high precipitation rates were longer in the mid‐Pliocene and shorter in the Last Glacial Maximum compared to the pre‐industrialLate Cenozoic hydroclimate of the region is linked to the dynamics of the mid‐latitude jet stream and the Indo‐Asian monsoon circulation [ABSTRACT FROM AUTHOR]

The surface sensible heating over the Tibetan Plateau (TP) is a significant, elevated heating source in spring (March‐April‐May, MAM). It exerts considerable thermal effects on both regional and global climate. During MAM, the surface sensible heating over the TP triggers a giant saddle‐like circulation anomaly in the upper troposphere at 200 hPa. Although this structure was observed a long time ago and it contributes to the stationary wave, its formation mechanism remains unclear. Using the Linear Baroclinic Model, we reveal the evolution of this structure in detail. In the initial state, a typical baroclinic anticyclone with a vertical phase tilt forms around the heating source. When the wave propagates downstream due to strong relative vorticity advection and favorable lower level circulation, an anticyclone with a barotropic structure forms downstream. Our analysis indicates that both the barotropic process and baroclinic process contribute to the formation of the saddle‐like structure, and the latter is associated with the spring unique background circulation and vertical heating structure over the TP. Plain Language Summary: Due to the special geographical and topographical features, the surface sensible heating over the Tibetan Plateau (TP) regulates atmospheric circulation considerably, especially in boreal spring. Many early studies find that the spring sensible heat over TP triggers a saddle‐like circulation anomaly in the upper troposphere. However, this phenomenon is not well understood. This study explores the phenomenon by a simplified model. The result indicates that the saddle‐like pattern evolution can be divided into initial state, adjustment process, and stationary state, in which interaction between different vertical levels is critical. Both the special background circulation in spring and the heating structure over the TP are essential to the formation of the saddle‐like response. Key Points: This study shows how an upper‐troposphere saddle‐like pattern forms as a result of surface sensible heating over the Tibetan PlateauDifferent from traditional stationary wave theory, the baroclinic process is concerned and its role in the pattern formation is emphasizedIn the 3 stages of stationary pattern formation, the forcing structure and westerly jet shape are both essential for the response pattern [ABSTRACT FROM AUTHOR]

The impact of soil moisture conditions on the triggering of afternoon convection over the Tibetan Plateau (TP) was investigated by applying the convective triggering potential (CTP) and humidity index framework developed by Findell and Eltahir (2003a, https://doi.org/10.1175/1525-7541(2003)004<0552:acosml>2.0.co;2, 2003b, https://doi.org/10.1175/1525-7541(2003)004<0570:acosml>2.0.co;2) using a slab model. Atmospheric sounding observations from May to September from 2015 to 2019 from 16 sites were used for the diagnosis. The results showed that the thresholds of CTP and humidity index in the lower‐layer atmosphere (HIlow) are distinct from other regions such as the United States and India, suggesting an easier triggering potential for the TP due to its high altitude induced lower air density and higher buoyancy. The convection over the TP is mainly affected by the atmospheric background. The percentages of soil moisture‐controlled cases is close to 50% mainly located in the broadly central TP. In addition, the positive feedback is mainly located in the center of the TP. Negative feedback appears in the southwest of the TP. Soil moisture is the most critical factor for precipitation triggering in soil moisture‐precipitation feedback, while wind speed can also have certain influences. The impact of soil moisture on different outcomes has no significant correlation with land surface elevation differences. Negative feedback in the southwest of the TP appeals to a necessary enhancement requirement for sounding observations in the western TP. Key Points: The thresholds of convective triggering potential and humidity index in the lower‐layer atmosphere are distinct from other regionsThe positive (negative) feedback is mainly located in the center (southwest) of the Tibetan PlateauThe Tibetan Plateau shows an easier soil moisture‐afternoon precipitation triggering potential due to its high altitude induced lower air density and higher buoyancy [ABSTRACT FROM AUTHOR]

Mesoscale convective systems (MCSs) have been identified as an important source of precipitation in the Tibetan Plateau (TP) region. However, the characteristics and structure of MCS‐induced precipitation are not well understood in this location. Infrared (IR) satellite imagery has been used for MCS tracking, but cirrus clouds or cold surfaces can lead to false MCS classification over mountain regions. Here, we combine brightness temperatures from IR imagery with satellite precipitation estimates from GPM IMERG and track MCSs over the TP, at the boundary of the TP (TPB), and in the surrounding lower‐elevation plains (LE), between 2000 and 2019. In most parts of LE and TPB, MCSs produced 50%–80% of the total summer precipitation (60%–90% of summer heavy precipitation), whereas MCSs over the TP account for below 10% of the total summer precipitation (10%–30% of summer heavy precipitation). Our results also show that MCSs that produce the largest amounts of heavy precipitation are characterized by longevity and large extents rather than by high intensities. These are mainly located in the populous areas south and east of the TP. A tracking of meso‐β convective systems over the TP shows that small‐scale convection makes a large contribution to total and heavy precipitation. This suggests that more localized convective systems are important for the regional water cycle over the higher terrain and highlights the importance of convective‐scale modeling to improve our understanding of precipitation dynamics in the TP region. Plain Language Summary: Storm systems that extend over several 100 km can represent a risk to people's lives and livelihoods, as they may lead to flooding, extreme winds and heavy rainfall. The Tibetan Plateau (TP) has received increasing attention over the last few decades because it has experienced drastic changes in the water cycle as a response to global warming. Although it is known that large storm systems develop in the populous surrounding regions of the TP, the rainfall characteristics from these storms are not well understood. It is difficult to identify storm systems in satellite images over high mountain regions, because high clouds and low surface temperatures can give signals similar to those of storm clouds. We therefore used a new method to track large storm systems in satellite images over the TP to clarify their role in the water cycle. Our results show that most of the storms that produce heavy rainfall occurred in the regions south and east of the TP. Storm systems over the TP are generally smaller in size and shorter in duration, which means that climate model simulations at high spatial resolution are needed to further investigate them. Key Points: Mesoscale convective systems (MCSs) were tracked in the Tibetan Plateau (TP) region for the past two decadesCo‐locations of brightness temperatures with precipitation indicate reduced numbers of MCSs over the TPPrecipitation and large‐scale environments associated with MCSs were compared between different subregions [ABSTRACT FROM AUTHOR]

This study investigated the factors controlling the interannual variability of Tibetan Plateau snow cover (TPSC) in winter using large‐ensemble simulations. Composite analysis reveals that years with high TPSC are associated with a positive Arctic Oscillation (AO)‐like pattern in which a strengthened subtropical westerly enhances zonal water vapor flux, resulting in greater precipitation over the Tibetan Plateau. Observations and simulations commonly show that TPSC tends to be high during the positive phase of AO, and vice versa. Meanwhile, the magnitude of the contribution of tropical sea surface temperature (SST) to TPSC is different based on observations and simulations. Observations indicate that TPSC is insensitive to El Niño/La Niña events, whereas the simulated ensemble mean TPSC is correlated strongly with Niño 3.4 SST index. In El Niño years, higher specific humidity and more numerous synoptic disturbances are found around the Tibetan Plateau. As several ensemble members show features close to those observed, the observed insensitivity of TPSC to El Niño–Southern Oscillation (ENSO) events is considered attributable to the limited sample size of the observations. This is corroborated in the analysis for a relatively short period, in which the observed TPSC is sensitive to ENSO. Comparison of the results of the historical simulations with those of the simulations without warming suggests that global warming has reduced the snow‐to‐rain ratio over the Tibetan Plateau, which is compensated by the overall increase in precipitation. Consequently, the impact of global warming on TPSC was negligibly weak until the 2000s. Key Points: Contributions of Arctic Oscillation (AO) and El Niño–Southern Oscillation (ENSO) to winter snow cover over the Tibetan Plateau are investigatedThe simulated snow cover is linked weakly to AO and strongly to ENSO unlike those suggested by observationsCombined impact of negative AO and La Niña reduces snow cover over the Tibetan Plateau [ABSTRACT FROM AUTHOR]

Peatlands store large amounts of carbon (C) and actively exchange greenhouse gases (GHGs) with the atmosphere, thus significantly affecting global C cycle and climate. Large uncertainty exists in C and GHG estimates of the alpine peatlands on Qinghai‐Tibetan Plateau (QTP), as direct measurements of CO2 and CH4 fluxes are scarce in this region. In this study, we provided 32‐month CO2 and CH4 fluxes measured using the eddy covariance (EC) technique in a typical alpine peatland on the eastern QTP to estimate the net C and CO2 equivalent (CO2‐eq) fluxes and investigate their environmental controls. Our results showed that the mean annual CO2 and CH4 fluxes were −68 ± 8 g CO2‐C m−2 yr−1 and 35 ± 0.3 g CH4‐C m−2 yr−1, respectively. While considering the traditional and sustained global warming potentials of CH4 over the 100‐year timescale, the peatland acted as a net CO2‐eq source (1,059 ± 30 and 1,853 ± 31 g CO2‐eq m−2 yr−1, respectively). The net CO2‐eq emissions during the non‐growing seasons contributed to over 40% of the annual CO2‐eq budgets. We further found that net CO2‐eq flux was primarily influenced by global radiation and soil temperature variations. This study was the first assessment to quantify the net CO2‐eq flux of the alpine peatland in the QTP region using EC measurements. Our study highlights that CH4 emissions from the alpine peatlands can largely offset the net cooling effect of CO2 uptake and future climate changes such as global warming might further enhance their potential warming effect. Key Points: CH4 emissions offset the net CO2 uptake from an alpine peatland on eastern Qinghai‐Tibetan PlateauThe alpine peatland showed a net radiative warming effectGlobal radiation and soil temperature were dominant abiotic controls of net CO2‐eq flux variations [ABSTRACT FROM AUTHOR]

The Qaidam Basin (QB) in the northeastern Tibetan Plateau held a megalake system during the Pliocene. Today, the lower elevations in the basin are hyperarid. To understand to what extent the climate plays a role in the maintenance of the megalake system during the Pliocene, we applied the Weather Research and Forecasting model for dynamical downscaling of ECHAM5 global climate simulations for the present day and the mid‐Pliocene. When imposing the mid‐Pliocene climate on the QB with its modern land surface settings, the annual water balance (ΔS), that is, the change in terrestrial water storage within the QB, increases. This positive imbalance of ΔS induced solely by the changes in the large‐scale climate state would lead to a readjustment of lake extent, until a new equilibrium state is reached, where loss due to evaporation over lake areas compensates for the input by runoff and precipitation. Atmospheric water transport (AWT) analysis at each border of the QB reveals that this imbalance of ΔS is caused by stronger moisture influx across the western border in winter, spring, and autumn and weaker moisture out‐flux across the eastern border in summer. These changes in AWT are associated with the strengthening of the midlatitude westerlies in all seasons, except for summer, and the intensification of the East Asian Summer Monsoon. Given that the mid‐Pliocene climate is an analog to the projected warm climate of the near future, our study contributes to a better understanding of climate change impacts in central Asia. Key Points: ECHAM5 global climate simulations for the present day and the mid‐Pliocene were dynamically downscaled over the Qaidam Basin (QB)Results show a positive imbalance in water balance when the mid‐Pliocene climate is imposed on the QB with its modern surface settingsThis imbalance in water balance is closely associated with changes in the midlatitude westerlies and in the East Asian Summer Monsoon [ABSTRACT FROM AUTHOR]

The Tibetan Plateau (TP) is known as Asian Water Tower and its atmospheric water cycle has been a lasting challenge to climate modeling community. Here, we compare two sets of the Met Office Unified Model simulations—one is a convection‐parameterized version (large‐scale model; LSM) and the other is a convection‐permitting model (CPM) simulation. The added value of the CPM in terms of atmospheric water cycle process is analyzed, including external moisture transport, fraction of atmospheric water vapor converting to precipitation and the precipitation recycle ratio. Results show that the simulated TP precipitation and evaporation for the summer of 2009 is significantly improved in the CPM. First, the overestimation of atmospheric water cycle by LSM is improved in CPM due to a reasonable representation of the fraction of atmospheric water vapor converting to precipitation. The overestimation of precipitation recycle ratio also indicates the LSM generates excessive convection compared to the CPM and therefore has a larger wet bias over the TP. Second, a better simulation of local precipitation has feedback on the circulation. Compared with the LSM, the less moisture convergence in the CPM is dominated by the stronger outflow through the eastern edge of the TP rather than the weaker inflow, implying the upscale effects of the resolved moist convection on the moisture transport over the TP. Our results imply that the CPM is a useful tool in the reproduction of moisture transport and atmospheric water cycle process over the Asian Water Tower and other regions of the world with complex topography. Plain Language Summary: The atmospheric water cycle over the Tibetan Plateau (TP, also as known as the Asian Water Tower) has been a challenge to climate models with convection parameterization. Benefiting from the high enough resolution, convection‐permitting model (CPM) can explicitly resolve the deep convection and therefore reduce the bias related with the convection parameterization scheme. Here, we compare a CPM with its low resolution version that employs convection‐parameterization in simulating atmospheric water cycle process over the TP. We find the precipitation and evaporation over the TP is significantly improved in the CPM. There is more water vapor flowing out of the TP and less water vapor in the atmosphere converting into the precipitation in the CPM, resulting in a reduced wet bias. CPM is free from the constrains of the convection parameterization scheme and therefore depicts the atmospheric water cycle over the TP better. Key Points: The convection‐permitting model (CPM) better reproduces precipitation over the Tibetan Plateau than convection‐parameterized model (large‐scale model [LSM])The overestimation of atmospheric water cycle by LSM is improved in CPM simulationThe interaction between large‐scale circulation and convection further reduces moisture convergence and wet bias in the CPM [ABSTRACT FROM AUTHOR]

This study analyzes the synoptic‐scale circulation patterns favorable for regional extreme precipitation events over southwest China (SWC) from 1979 to 2018 occurring during the rainy seasons. The whole SWC is regionalized into two subregions, western SWC and eastern SWC, according to the spatial distribution of two extreme precipitation indices. Furthermore, the atmospheric patterns associated with the independent regional extreme precipitation events (REPEs) that occurred over the two subregions are categorized into two types using k‐means clustering. For type 1, a Rossby wave train originating from the Northeast Atlantic almost a week before REPEs leads to an anomalous low over the eastern Tibetan Plateau (TP), inducing upper‐troposphere divergence and ascending motion over SWC. Moreover, anomalous convective activities over India and the Bay of Bengal (the enhanced and westward‐extended western Pacific subtropical high) are critical precursors of REPEs over western (eastern) SWC. For type 2, an anomalous high is developed over the Ural Mountains at least a week prior to REPEs. The subsequent anomalous low over Lake Baikal and eastward‐shifted South Asian high are conducive to forming updrafts over SWC. An anomalous anticyclone at the middle‐to‐lower troposphere south of the TP is the main moisture contributor. Discrepancies in the zonal location of the Lake Baikal low and the strength of the Ural Mountain high, as well as the intensity of atmospheric circulation anomalies at low latitudes, are the major differences between the type 2 events occurring in western and eastern SWC. Key Points: Two types of atmospheric circulation anomalies are favorable for extreme precipitation events over southwest China during rainy seasonsRossby wave trains from the Northeast Atlantic and the Ural Mountains are critical precursors of the extreme precipitation eventsThe low‐latitude atmospheric circulation anomalies mainly determine the spatial differences and the extremeness of the events [ABSTRACT FROM AUTHOR]

The Tibetan Plateau (TP) is characterized by complex topography and heterogeneous surface cover, which makes it difficult to obtain accurate precipitation data at a regional scale. Therefore, it is important to use dense ground observations to evaluate satellite‐derived precipitation products. In this study, the top‐down‐based Global Precipitation Measurement Integrated MultisatellitE Retrievals (GPM IMERG) and bottom‐up‐based Soil Moisture TO RAIN‐Advanced SCATterometer (SM2RAIN‐ASCAT; SM2RASC) precipitation products were evaluated against 1,584 unevenly distributed rain gauges over the TP from May to October 2015. Results show: (1) The overall performances of IMERG and SM2RASC are comparable at the daily scale, with a higher correlation coefficient (CC) for IMERG and lower root‐mean‐square error (RMSE) for SM2RASC. Regarding the precipitation detectability, IMERG outperforms SM2RASC; (2) Spatially, SM2RASC shows better performance than IMERG in grasslands, but IMERG outperforms SM2RASC in forest areas, due to the low quality of the soil moisture retrieved by satellite in the areas; (3) The accuracy of both SM2RASC and IMERG is closely correlated with altitude and rainfall intensity. The SM2RASC product estimates light to moderate rainfall (5–25 mm/day) more accurately than the IMERG, but the IMERG product shows better performance for drizzle and heavy rainfall (>25 mm/day). Due to relatively frequent fluctuations of the ASCAT soil moisture product, SM2RASC frequently reports false rainfall in dry conditions. This study demonstrates the good performance of the SM2RASC product over the TP and suggests that the impact of vegetation density and topography should be considered for improving the SM2RAIN algorithm. Key Points: Soil Moisture TO RAIN‐Advanced SCATterometer (SM2RAIN‐ASCAT) estimates daily rainfall better in grassland areas, and the Global Precipitation Measurement‐Integrated MultisatellitE Retrievals for GPM (GPM IMERG) product outperforms in forestsSM2RAIN‐ASCAT estimates light to moderate rainfall more accurately than GPM IMERG, but it cannot detect heavy rainfall eventsDue to relatively frequent fluctuations of ASCAT soil moisture product, SM2RAIN‐ASCAT frequently reports false rainfall in dry conditions [ABSTRACT FROM AUTHOR]

Current climate model resolution cannot accurately describe the complex topography over the Tibetan Plateau, which limits our understanding of past and future precipitation over this region. This study investigates the daily precipitation characteristics and its future changes over the Tibetan Plateau, especially for the southern slope of Tibetan Plateau (SSTP), by 14‐km Nonhydrostatic ICosahedral Atmospheric Model (NICAM) with explicitly calculated convection for historical and future 30‐years period. By comparing with the satellite Global Precipitation Measurement (GPM), NICAM well reproduces the historical precipitation spatial pattern, seasonal cycle, and the extreme precipitation belt over SSTP, but overestimates precipitation amount by ∼35%. It is found that heavy precipitation probability decreases as elevation becomes higher while the light precipitation generally shows the opposite. For the precipitation changes during June to September from 1979–2008 to 2075–2104, NICAM predicts that mean precipitation will decrease over low‐level SSTP but increase over high‐level SSTP. Nonprecipitation and heavy precipitation probability will increase while light precipitation probability will decrease in the future over SSTP. The extreme precipitation probability and intensity will increase ∼50%/°C and ∼8%/°C over SSTP, and this increase is more obvious as elevation becomes higher. The robust increase of extreme precipitation along the SSTP topography is unique and has not been identified by the climate model simulations before. The strong meridional gradient of specific humidity over SSTP is found to be further enhanced under global warming, and this gradient enhancement is suggested to be responsible for the increase in the extreme precipitation over SSTP. Key Points: NICAM well reproduces precipitation spatial pattern, seasonal cycle, and extreme precipitation belt over SSTP as compared with observationsFuture mean precipitation over SSTP during the summer will decrease over lower SSTP but increase over higher SSTP from NICAM simulationThe projected extreme precipitation will increase along the SSTP topography, especially over higher SSTP, at the end of the 21st century [ABSTRACT FROM AUTHOR]

The comprehensive understanding of the occurred changes of permafrost, including the changes of mean annual ground temperature (MAGT) and active layer thickness (ALT), on the Qinghai‐Tibet Plateau (QTP) is critical to project permafrost changes due to climate change. Here, we use statistical and machine learning (ML) modeling approaches to simulate the present and future changes of MAGT and ALT in the permafrost regions of the QTP. The results show that the combination of statistical and ML method is reliable to simulate the MAGT and ALT, with the root‐mean‐square error of 0.53°C and 0.69 m for the MAGT and ALT, respectively. The results show that the present (2000–2015) permafrost area on the QTP is 1.04 × 106 km2 (0.80–1.28 × 106 km2), and the average MAGT and ALT are −1.35 ± 0.42°C and 2.3 ± 0.60 m, respectively. According to the classification system of permafrost stability, 37.3% of the QTP permafrost is suffering from the risk of disappearance. In the future (2061–2080), the near‐surface permafrost area will shrink significantly under different Representative Concentration Pathway scenarios (RCPs). It is predicted that the permafrost area will be reduced to 42% of the present area under RCP8.5. Overall, the future changes of MAGT and ALT are pronounced and region‐specific. As a result, the combined statistical method with ML requires less parameters and input variables for simulation permafrost thermal regimes and could present an efficient way to figure out the response of permafrost to climatic changes on the QTP. Key Points: The combined statistical method with machine learning is efficient to obtain the thermal regime of permafrost on the Qinghai‐Tibet Plateau (QTP)The present permafrost area on the QTP is ∼1.04 × 106 km2, and the average mean annual ground temperature and active layer thickness are −1.35 ± 0.42°C and 2.3 ± 0.60 m, respectivelyThe future changes of permafrost are projected to be pronounced due to climate change, but region‐specific [ABSTRACT FROM AUTHOR]

This study investigates the interdecadal variation in early spring rainfall over the southeastern edge of the Tibetan Plateau (SEETP) during 1979–2015 and its possible causes using mainly Asian Precipitation–Highly‐Resolved Observational Data Integration Toward Evaluation daily precipitation data set, ERA5 reanalysis data and the atmospheric general circulation model ECHAM6. A significant interdecadal change in early spring rainfall over the SEETP occurred with its node around 1998/1999. The early spring rainfall over the SEETP was heavier in 1979–1998 than in 1999–2015, reflecting a reduction in moderate and heavy rain during the early spring. The covariability of the Pacific Decadal Oscillation (PDO), Atlantic Multidecadal Oscillation (AMO), and Indian Ocean Basin Mode (IOBM) is an important driver of the interdecadal decrease in early spring rainfall over the SEETP. When the PDO is in a cold phase, and the AMO and IOBM are in positive phases, an anomalous cyclone is excited over the Bay of Bengal‐western Pacific in the lower to middle troposphere. Anomalous easterly winds on the north flank of the anomalous cyclone lead to the interdecadal decrease in early spring rainfall over the SEETP by reducing water vapor transport from the Indian Ocean and producing divergence over the SEETP. This diagnosis of the key physical process linking the associated sea surface temperature anomalies with the interdecadal variation in early spring rainfall over the SEETP is supported by numerical experiments. Key Points: A significant interdecadal variation in early spring rainfall over the southeastern edge of the Tibetan Plateau (SEETP) occurred in 1998/1999The covariability of the Pacific Decadal Oscillation (PDO), Atlantic Multidecadal Oscillation (AMO), and Indian Ocean Basin Mode (IOBM) drives the interdecadal variation of early spring rainfall over the SEETPThe India‐Burma trough and western Pacific subtropical high anomalies link the early spring rainfall anomalies over the SEETP with the covariability of the PDO, AMO, and IOBM together [ABSTRACT FROM AUTHOR]

The East Asian summer monsoon (EASM) has complex drivers and is characterized by an abrupt onset and northward jumps of the main rain band. By analyzing multisource observational data and reanalysis data sets during 1961–2016, we addressed the connection between the preceding diabatic heating of the Tibetan Plateau (TP) and the seasonal march of the EASM. We show that the positive surface sensible heating and condensation heating anomalies over the TP lead the onset, duration, and total precipitation of the rainy season in South China (the first stage of the EASM) by about 2 and 1 month, respectively. A significant positive condensation heating anomaly over the TP can be detected about 1 month before the onset of the rainy season in Southwest China (the second stage of the EASM). By contrast, the relationship between heating of the TP and the onset of the rainy season is relatively weak during the remaining stages of the EASM, including the Meiyu and North China rainy seasons. We suggest that the strong heating of the TP intensifies the low‐level southwesterly circulation to the southeast and facilitates the convergence of moisture and ascending motion, leading to an earlier onset of the rainy season. Sensitive experiments with a linear baroclinic model further confirmed the role of heating of the TP in generating circulation conditions favorable for the onset of the rainy season in both South and Southwest China. The TP heating anomaly therefore acts as a precursor of the early stage onset of the EASM. Plain Language Summary: The East Asian summer monsoon (EASM) is the strongest subtropical monsoon and shows substantial variations from year to year in terms of the onset date, duration, and total precipitation, although the factors controlling this variation are not clear. We analyzed data from both observations and reanalysis data sets and used a numerical simulation to show that the preceding diabatic heating of the atmosphere over the Tibetan Plateau is the main driver of the seasonal march of the early stages of the EASM (i.e., the mean onset of the South China rainy season in early April and the Southwest China rainy season in late May). This is because the positive Tibetan Plateau heating anomaly intensifies the circulation conditions favoring monsoon rainfall in these areas, including the low‐level southwesterly circulation, which carries abundant water vapor from the tropical oceans, moisture convergence and upward motion. These results suggest that the Tibetan Plateau heating anomaly can be regarded as a precursor of the onset of the EASM. Key Points: The onset of the rainy season in South and Southwest China is closely related to the preceding heating of Tibetan PlateauThe heating of Tibetan Plateau influences the circulation and moisture conditions for the rainy season onset in South and Southwest ChinaThe Tibetan Plateau is an independent driver of the East Asian summer monsoon separated from the remote atmospheric and oceanic modes [ABSTRACT FROM AUTHOR]

How climate change influences lake ice phenology is important in understanding the climate‐lake interactions. This study investigates the response of lake ice phenology to future climate scenarios. Thirty‐five lakes in the Tibetan Plateau were studied. Firstly, we applied a random forest (RF) model to simulate lake ice condition under different representative concentration pathways (RCPs). The results of the virtual experiments show that lake ice freeze‐up start date (FUSD) and break‐up end date (BUED) are well simulated by the RF model, with R2FUSD > 0.91 under different RCPs, and R2BUED > 0.84, except in RCP2.6 (R2 = 0.74). Secondly, two non‐parametric methods (Mann‐Kendall and Sen's slope estimator) were used for analyzing the trends in lake ice phenology and its response to various emission scenarios. Lake ice phenology was largely affected by temperature changes under different RCPs, and it had a larger inter‐annual variability in the early period (2002–2050) than in the later period (2050–2099). FUSD of 35 lakes delayed by an average of 0.01, 0.04, and 0.04 days/yr from 2002 to 2098 under RCP4.5, RCP6.0, and RCP8.5, whereas BUED advanced by an average of 0.04, 0.11, and 0.21 days/yr from 2003 to 2099. Both delays in FUSD and advances in BUED contributed to shortened average ice duration of 35 lakes, which shortened by 0.05, 0.14, and 0.25 days/yr from 2002 to 2098 under RCP4.5, RCP6.0, and RCP8.5, respectively. These findings could help to tackle the impacts of climate change on the lake systems. Plain Language Summary: The impacts of future climate scenarios on lake ice phenology is important in understanding the climate‐lake interactions. Thirty‐five lakes in the Tibetan Plateau were studied. We employed a random forest (RF) model to simulate lake ice condition under different representative concentration pathways (RCPs). The results of the virtual experiments show that lake ice freeze‐up start date (FUSD) and break‐up end date (BUED) are well simulated by the RF model, under different RCPs. FUSD of 35 lakes delayed by an average of 0.01, 0.04, and 0.04 days/yr from 2002 to 2098 under RCP4.5, RCP6.0, and RCP8.5, whereas BUED advanced by an average of 0.04, 0.11, and 0.21 days/yr from 2003 to 2099. Both delays in FUSD and advances in BUED contributed to shortened average ice duration of 35 lakes, which shortened by 0.05, 0.14, and 0.25 days/yr from 2003 to 2098 under RCP4.5, RCP6.0, and RCP8.5, respectively. Our results could help to tackle the impacts of climate change on the lake systems. Key Points: The pace of lake ice phenology change showed quite different characteristics across six sub‐basins in the inner TPAdvances in break‐up end date and delays in freeze‐up start date result in shortened ice duration under RCP4.5/6.0/8.5Inter‐annual variation of lake ice phenology increases with increasing CO2 concentration in the air [ABSTRACT FROM AUTHOR]

The rapid warming and consequent retreat of glaciers across the Tibetan Plateau (TP) have given rise to the debate on the ability of the atmospheric water supply to alleviate the depletion of surface water storage. We investigate long‐term changes in atmospheric water vapor balance across the TP using 40‐year fifth generation European Centre for Medium‐Range Weather Forecasts (ECMWF) (ERA5) reanalysis. Precipitation, water vapor convergence, and evaporation generally maintain an equilibrium but with different long‐term variation trends: 0.68, −0.18, and 0.69 mm/a, respectively. Results suggest the inability of the water vapor arriving from outside the TP to effectively replenish the surface water storage. Despite of huge changes in atmospheric water vapor balance during summer, the risk of water storage depletion is brought by other three seasons, especially the autumn. The climatology and long‐term trends of water vapor balance exhibit strong variation across the regions of TP. The surrounding areas of Yarlung Zangbo Grand Canyon experience sharp decrease in water vapor convergence, thus reducing precipitation. Moreover, increasing evaporation is expected to severely loss of surface water storage. For the Three Rivers Source Region with no significant changes in total precipitations, decrease in water transported from outside of TP overlaps increase in evaporation results in the possible depletion of surface water storage. Brahmaputra basin, inner TP, and Qilian Mountain exhibit significant wetting trends due to increases in both convergence of water vapor flux and evaporation. Above regional and seasonal characteristics of water vapor, balances across the TP are attributed by inhomogeneous variation of atmospheric heat source and complex changes of atmospheric circulations. Plain Language Summary: We aim to determine whether the increase in atmospheric water vapor is able to replenish the surface water storage depletion across the Tibetan Plateau (TP) by analyzing long‐term trends in precipitation, water vapor convergence, and evaporation. Results suggest that surface water storage will not be overall replenished by precipitation for the whole year, as despite the increase in water vapor from local evaporation, transportation from outside of the TP is reduced. Furthermore, long‐term trends in the water vapor balance and their impacts on surface water storage vary from place to place across the TP. Key Points: Despite that air of Tibetan Plateau is moistening, atmospheric water supply is not able to alleviate the depletion of the surface water storageRegions around Yarlung Zangbo Grand Canyon suffer severe loss of water storage due to the overwhelming decrease in water vapor convergenceThe surface water storage of the Three Rivers source region is also under risk of depletion [ABSTRACT FROM AUTHOR]

The reasons for the Holocene temperature conundrum, known as the inconsistency between the reconstructed cooling and the inferred warming simulations during the Holocene, remain unclear. Temperature reconstructions from the Tibetan Plateau (TP) provide important insights for understanding the Holocene temperature conundrum due to enhanced sensitivity to climate at high altitudes. Given the significant positive correlation between air temperature and δ18O in precipitation over the northern TP, the stable isotopic records of ice cores recovered from this area are widely used for paleotemperature reconstruction. Here we present a new high‐resolution δ18O record from the Chongce ice cores to bedrock, dated back to 7 ka BP by the accelerator mass spectrometry (AMS) 14C dating technique. Our reconstructed temperature record shows a long‐term warming trend until ~2 ka BP, followed by an abrupt change to a relatively cool period until the start of the industrial‐era warming. This record challenges the widely recognized Holocene reconstruction from the neighboring Guliya ice core. It is also different from many previous temperature reconstructions, most of which have summer biases and show a long‐term cooling trend over the past two millennia. In addition, our record shows that temperatures during the recent decades are almost the highest during the past 7 ka BP, highlighting the unusual warming forced by anthropogenic greenhouse gases. Key Points: A new high‐resolution ice core δ18O record dated back to 7 ka BP from the northwestern Tibetan Plateau was presentedThe record shows a long‐term warming trend between 7 and 2 ka BP and followed by a cool period until the start of the industrial‐era warmingTemperatures during the recent decades are almost the highest during the past 7 ka BP [ABSTRACT FROM AUTHOR]

The Tibetan Plateau has experienced substantial warming during the last few decades. As a result, the cryosphere of the Tibetan Plateau, including the snow cover, has shown significant changes. We characterized the changes in snow over the Tibetan Plateau using several snow‐related indices, including snow depth and snow‐covered days based on the MERRA‐2 and JRA‐55 reanalysis data set and passive microwave (MW) satellite observations. The analyses were performed over different time periods—including the last 38, 30, 20, and 10 snow seasons—from 1980 to 2018. The results show that the significant trends in snow depth and snow‐covered days are dependent on both the season and region and vary with the data set and snow‐related index used. There was a clear decrease in the annual maximum consecutive snow‐covered days (CSCDMax), and this was characterized by a later begin time and an earlier end time for both MERRA‐2 and JRA‐55, but only a later begin time for MW during the time period 1980–2018. The changes in CSCDMax were generally dominated by changes in the begin time, which were mainly caused by the increase in the average 2‐m air temperature for November–December. The relatively weak trends in the end time were a result of the combined impact of warmer temperatures and more precipitation in March–April. The CSCDMax averaged over the Tibetan Plateau showed decreasing trends in all studied time periods for JRA‐55 and MW and in the last 38 and 10 snow seasons for MERRA‐2 during the time period 1980–2018. Key Points: The changes in snow show remarkable regional and seasonal differences and vary with data set and snow‐related index usedMost of the time series during 1980–2018 show a reduction in snow depth and snow‐covered days averaged over the Tibetan PlateauThe trends in the begin time of the annual maximum consecutive snow‐covered days are relatively stronger than in the end time [ABSTRACT FROM AUTHOR]