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During its 6,300-km course from the Tibetan Plateau to the ocean, the Yangtze River is joined by two large lakes: Dongting Lake and Poyang Lake. We explain why these lakes exist. Deglaciation forced the ocean adjacent to the Yangtze mouth to rise ∼120 m. This forced a wave of rising water surface elevation and concomitant bed aggradation upstream. While aggradation attenuated upstream, the low bed slope of the Middle-Lower Yangtze River (∼2 × 10-5 near Wuhan) made it susceptible to sea level rise. The main stem, sourced at 5,054 m above sea level, had a substantial sediment load to “fight” against water surface level rise by means of bed aggradation. The tributaries of the Middle-Lower Yangtze have reliefs of approximately hundreds of meters, and did not have enough sediment supply to fill the tributary accommodation space created by main-stem aggradation. We show that the resulting tributary blockage likely gave rise to the lakes. We justify this using field data and numerical modeling, and derive a dimensionless number capturing the critical rate of water surface rise for blockage versus nonblockage. [ABSTRACT FROM AUTHOR]

Caragana is endemic to temperate Asia, with most species distributed on the Qinghai–Tibetan Plateau (QTP) and in Northwestern China. Consequently its biogeography should be hypothesized to have been affected by QTP uplift. To examine the biogeography of Caragana in relation to QTP uplift and consequent interior aridification, we conducted molecular dating analyses based on three genes (ITS, cpDNA trnS- trnG and rbcL). Results from relaxed Bayesian BEAST, relaxed Bayesian Multidivtime, and PL (penalized likelihood) indicate that QTP uplift, especially the onset of Himalayan motion at 21–17 Ma, triggered the origin of Caragana (with estimated ages 16–14 Ma). The subsequent QTP rapid uplift at 8 Ma is inferred to have driven the evolution and diversification of the three major clades of Caragana: section Caragana (northern China and the Junggar–Altai–Sayan region), section Frutescentes (Central Asia), and sections Bracteolatae and Jubatae, centered in the QTP. A rapid and active speciation process occurring in the QTP intense uplift at 3.4–1.8 Ma, is indicated by the chronogram. [ABSTRACT FROM AUTHOR]

The Songpan-Garze fold belt, located in the eastern part of the Tibetan Plateau, covers a huge triangular area bounded by the Yangtze (South China), the North China and the Tibetan Plateau blocks. In the northeastern part of the Songpan-Garze fold belt, the Yanggon and Maoergai granitoids provide insights into regional tectono-magmatic events, basement nature and tectonic evolution. U–Pb zircon SHRIMP dating shows that the Yanggon and Maoergai granitoids have magmatic crystallization ages of 221 ± 3.8 Ma and 216 ± 5.7 Ma, respectively. Both the granitoids display adakitic geochemical signatures, suggesting that their magma was derived from partial melting of thickened lower crust. Pb–Sr–Nd isotopic compositions for granitoids reveal that there is an unexposed Proterozoic basement in the Songpan-Garze belt, which has an affinity with the Yangtze block. During development of the Paleo-Tethys ocean, the basement of the Songpan-Garze belt would be a peninsula approaching the Paleo-Tethys ocean from the Yangtze block. [ABSTRACT FROM AUTHOR]

The genus Caragana Fabr., consisting of approximately 70 species, has a temperate Asian distribution and occurs mainly in the drought and cold regions of the northwestern and southwestern Tibetan Plateau of China. The distribution pattern of the genus was investigated using dispersal-vicariance analysis (DIVA). The results indicate that vicariance versus dispersal plays a major role in the evolution of the genus and that short-distance dispersal also exists. There is no fossil record of this genus. Therefore, Caragana is inferred as an advanced taxon in terms of its limited temperate Asian distribution. Based on the morphological variation and ecological adaptation in Caragana, the generic speciation is postulated to be related to the uplifting of the Tibetan Plateau and to the increasing arid conditions of Central Asian lands since the Neogene. The Mongolian Plateau and the Tibetan Plateau are hypothesized as the barriers of vicariance between East Asia and western Central Asia. (Managing editor: Ya-Qin) [ABSTRACT FROM AUTHOR]

The mechanisms driving crustal deformation and uplift of orogenic plateaus are fundamental to continental tectonics. Large‐scale crustal flow has been hypothesized to occur in eastern Tibet, but it remains controversial due to a lack of geologic evidence. Geochemical and isotopic data from Cenozoic igneous rocks in the eastern Tibet‐Gongga‐Zheduo intrusive massif, provide a way to test this model. Modeling results suggest that Cenozoic magmas originated at depths of ∼30–40 km, the depth that crustal flow has been postulated to occur at. Detailed isotopic analyses indicate that the igneous rocks are derived from partial melting of the local Songpan‐Ganzi crust, arguing against a long‐distance crustal flow. Episodic magmatism during the Cenozoic showing a repeated shifting of magmatic sources can be correlated with crustal uplift. The continued indentation of the Indian Block and upwelling of the asthenosphere contribute to the crustal deformation, magmatism, and uplift. Plain Language Summary: How the Tibetan Plateau grows outward and deformed remains controversial. A large‐scale crustal flow model has been favored for the expansion of the southeast Tibetan Plateau, arguing that crustal materials could flow hundreds of km resulting in crustal thickening and uplift. Detailed geochemical and isotopic investigations on the largest intrusion (Gongga‐Zheduo) in the eastern margin of the Tibetan Plateau show that their magmatic source is local crustal rocks of the Songpan‐Ganzi terrane without the input of crustal materials from central Tibet. Thermodynamic and trace element modeling results show that the Cenozoic magma is derived from ∼30 to 40 km depth, similar to the depth of postulated crustal flow. The results are inconsistent with the large‐scale eastward crustal flow model. A repeated shifting of magmatic sources during the Cenozoic is correlated with crustal uplift. Mantle‐crust interaction plays a primary role in the formation of magmatism and modifying crustal rheology. The continued collision between the Indian and Asian blocks and upwelling of the asthenosphere contribute to the crustal deformation and uplift. Key Points: Isotopic and thermodynamic modeling results indicate that Gongga‐Zheduo granitic rocks in eastern Tibet are sourced from the local crustNo crustal materials from central Tibet are observed in eastern Tibet arguing against the large‐scale crustal flow modelCenozoic episodic magmatism in eastern Tibet with a repeated vertical shifting of sources is correlated with staged crustal uplift [ABSTRACT FROM AUTHOR]

Over‐estimation of summer precipitation over the Tibetan Plateau (TP) is a well‐known and persistent problem in most climate models. This study demonstrates the impact of a Gaussian Probability Density Function cloud fraction scheme on rainfall simulations using the Weather Research and Forecasting model. It is found that this scheme in both 0.1° and 0.05° resolutions significantly reduces the wet bias through both local feedbacks and large‐scale dynamic process. Specifically, increased cloud water/ice content with this scheme reduces surface shortwave radiation, and consequently surface heat fluxes and evapotranspiration. This, in turn, dampens the large‐scale thermal effect of the TP and weakens the exaggerated monsoon circulation and low‐level moisture convergence. It is this large‐scale dynamic process that contributes the most (∼70%) to the wet bias reduction. Although this paper presents a modeling study, it highlights the cloud radiative feedback to the large‐scale dynamics and precipitation over the TP. Plain Language Summary: Despite numerous attempts to correct the overestimation of summer precipitation over the Tibetan Plateau (TP) in current global and regional climate models, the issue persists. This study applies the Gaussian Probability Density Function (GPDF) cloud fraction scheme in the Weather Research and Forecasting model at two different resolutions (0.1° and 0.05°) during a summer over the TP. The results show that the GPDF scheme significantly mitigates the precipitation overestimation, particularly in the high‐resolution modeling. We explored the physical processes, both local and remote, that contribute to this improvement. Specifically, an increase in cloudiness reduces the amount of radiation reaching the land surface. This decrease in surface radiative heating not only reduces local evaporation but also weakens the thermal effect of the TP. The latter is a major driver of the South Asian monsoon that conveys moisture to the TP, and its weakening reduces moisture convergence over the TP. Both the decreases in local evaporation and remote moisture convergence contribute to the alleviation of the precipitation overestimation, and the latter plays a dominant role. These findings provide a unique perspective for reducing the wet bias over the TP, focusing on the surface available energy and associated remote moisture processes. Key Points: The use of the Gaussian Probability Density Function cloud fraction scheme in high resolution greatly reduces wet bias over the Tibetan Plateau (TP) during summerMore cloud water/ice with the scheme lessens TP's thermal effect, causing a weaker South Asian monsoon and moisture convergenceWet bias reduction is mainly governed by the decrease in remote moisture rather than local evapotranspiration [ABSTRACT FROM AUTHOR]

Simple Summary: Freshwater ecosystems are embedded in terrestrial ecosystems to form an integral whole. In the context of global climate change, freshwater ecosystems may be irreversibly negatively affected; thus, aquatic organisms dependent on freshwater ecosystems are severely affected. However, terrestrial life may also experience unexpected crises due to the collapse of freshwater ecosystems, and we know very little about the relationship between terrestrial life and freshwater ecosystems. Therefore, we conducted our research on the Tibetan Plateau, an area with a dense distribution of lakes. We analyzed the relationship between the number of Tibetan antelopes (an ungulate mammal distributed in the region) and the number of lakes, and the distribution of the terrain and vegetation around the lake. Our results indicated that a greater abundance of Tibetan antelopes was associated with larger lakes, flatter terrain, and proximity to lakes, which may all be factors that affect the survival of this species. Our study suggests that lakes may provide a better habitat for ungulates in such a fragile ecosystem, including a different predation risk and more food resources, and this also provides a new research idea for the study of multi-species coexistence on the Tibetan Plateau. The influence of freshwater ecosystems on terrestrial taxa in high-altitude regions with challenging access, such as the Tibetan Plateau, remains inadequately understood. This knowledge gap is particularly significant due to the fragility of these ecosystems, characterized by low primary productivity. Ungulates, in particular, may exhibit high sensitivity to even minor alterations in plant availability, potentially stemming from global climate change. Consequently, the investigation of these ecosystems may offer valuable insights into addressing future challenges posed by climate change. Here, to fill this knowledge gap, we explore the relationship between lakes and Tibetan antelopes in an even more vulnerable region, the Tibetan Plateau. We found that the Tibetan antelope population was higher in areas with larger lakes, and where the terrain near the lakes was flatter. At the same time, vegetation cover and plant diversity were higher near the lake compared to areas farther away from the lake. This phenomenon can be elucidated by the fact that lakes offer Tibetan antelopes a richer food supply and reduced predation risk. Our study provides new perspectives for researchers to explore the cross-ecosystem impacts of climate change. [ABSTRACT FROM AUTHOR]

To study the viscosity coefficient and thickness of the viscous layer on the Tibetan Plateau, the relationship between the change in viscosity coefficient and thickness of a lower crustal flow and the change in elevation has been investigated based on the principle of a pipeline flow with different viscosity and thickness of terrain elevation. The viscosity and thickness of the lower crustal flow in different directions were determined based on the changes in the terrain along different directions on the Tibetan Plateau. The following results were obtained: (1) The greater the viscosity and the smaller the thickness of the lower crustal conduit flow, the steeper the ground elevation change formed; (2) The maximum viscosity coefficient in the region from India to the Kunlun Mountains in the southern Tibetan Plateau through the Himalayan boundary is approximately 1020Pas, and the thickness of the conduit flow is approximately 25 km. (3) The maximum value of the viscosity coefficient of the lower crustal flow in the region ranging from the Tibetan Plateau to the Qinghai- Gansu section is attained when the flow thickness in this region approaches 40 km (4) The maximum value of the viscosity coefficient of the lower crustal flow in the region ranging from the Tibetan Plateau to the Qinghai- Gansu section is attained when the flow thickness in this region approaches 40 km., which does not substantially differ from that of the region ranging from the Tibetan Plateau to the Qinghai-Gansu area. (5) The maximum viscosity coefficient of the lower crustal flow from the southeast of the Tibetan Plateau to Yunnan is approximately 1018Pas, and the thickness is approximately 32 km, which differs from the flow thickness in the Sichuan Basin and Qinghai-Gansu regions. The results show variations in the viscosity of the flow along different directions on the Tibetan Plateau, in addition to considerable variation in the thickness of the lower crustal channel flow from region to region, with the overall characteristics of thinness in the west and thickness in the east. The results of the four profiles reveal that the channel flow thickness is the steepest at the southwest border of the Tibetan Plateau with India. This paper presents a reasonable interpretation of the geomorphology of the Tibetan Plateau using different thickness and viscosity coefficients of the lower crustal channel flow model. In this paper, a possible mechanism for the formation of the Tibetan Plateau topography is explained using a horizontal pipe flow for four profiles of the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

Vegetation is the most vulnerable component of terrestrial ecosystems to climate change. In recent decades, there has been a significant warming and humidification trend in the Tibetan Plateau. It is crucial to study and analyze the impact of these changes on the ecosystem and their future trends for protecting the Tibetan Plateau's ecosystem. This study collected and analyzed climate (temperature, precipitation) data and vegetation index data (the normalized difference vegetation index (NDVI) and the leaf area index (LAI)), as well as data from significance tests combined with Mann–Kendall tests and Sen's slope estimation. The effects of temperature and precipitation factors on vegetation indices were revealed, leading to a multiple regression model predicting NDVI and LAI value changes under climate change from 2021 to 2100. The results indicate a general increase in temperature and precipitation levels across the Tibetan Plateau between 2000 and 2020. The climate experienced a clear pattern of warming and moist conditions, with the southeast region experiencing warmer and wetter conditions, and the northwest region experiencing drier and colder conditions. The trends of the LAI and NDVI values of the Tibetan Plateau indicated a general increase, with a gradual decline from the southeast to the northwest. Precipitation and temperature were differentially correlated with the NDVI and LAI values across various regions of the plateau. Between 2021 and 2100, the Tibetan Plateau is expected to experience year-on-year increases in both precipitation and temperature levels. However, the increase in precipitation was found to be less significant than that of the climate and, comparatively, smoother. There is a certain correlation between the NDVI and LAI values, and the changes in temperature and precipitation. The variations of both are more influenced by temperature than precipitation, with an overall increasing trend observed over the years, which is also quite evident. This study could serve as a scientific foundation and a point of reference for monitoring vegetation changes over a long period of time on the plateau, as well as for the planning and execution of ecological development in the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

Reliable precipitation simulation over the Tibetan Plateau (TP) remains a challenge, manifested by a prominent systematic wet bias in the warm season. Previous studies have generally neglected the potential linkage between surface radiation energy budget and precipitation bias. Prevalent scattered cumulus and thunderstorms over the TP in summer strongly influence surface radiation. A cloud fraction scheme considering subgrid temperature and humidity fluctuations is implemented in the WRF model and tested for a month‐long simulation. It is found that the scheme better reproduces the surface solar radiation compared to a default cloud fraction scheme in the WRF model. Using abundant surface observations, we find that overestimation of the downward surface shortwave radiation (DSSR) would lead to wet bias. DSSR overestimation contributes to higher surface temperature and larger evaporation and enhanced atmospheric instability, which favor more simulated convective precipitation. The study suggests that a better simulation of clouds and surface radiation would benefit precipitation simulation over the plateau. Plain Language Summary: Summer precipitation over the Tibetan Plateau (TP) is generally overestimated in general circulation models as well as regional weather forecasts and climate models. The prevailing "popcorn‐like" clouds over the TP in summer would strongly impact surface radiation. Considering the potential linkage between surface radiation energy budget and precipitation bias, a statistical cloud fraction and subgrid condensation scheme (GS‐PDF scheme) is implemented in the WRF model and tested for a month‐long simulation. The GS‐PDF scheme better captures clouds over the TP with more mid‐low cloud water (ice) than the default Xu‐Randall scheme. Increased mid‐low cloud water in the GS‐PDF scheme reduced simulated downward surface shortwave radiation, reduced simulated surface temperatures, atmospheric instabilities and convective precipitation, leading to alleviated wet bias over the TP. This study suggests that better simulations of cloud and surface radiation would be beneficial for simulations of hydrological cycles over the TP. Key Points: A new cloud macrophysics scheme considering subgrid temperature and humidity fluctuations is implemented in the WRF modelThe new macrophysics scheme reduced simulated downward surface shortwave radiation, surface temperatures and atmospheric instabilitiesA better simulation of clouds and surface radiation would benefit precipitation simulation over the Tibetan Plateau [ABSTRACT FROM AUTHOR]

The onset date of the South China Sea (SCS) summer monsoon (SCSSM) and the generation time of the first tropical cyclone (TC) over the Bay of Bengal (BoB) during late April and early June were significantly correlated with a correlation coefficient of 0.58 during 1979–2020. The composite analysis found that under the impact of BoB TCs, an enhanced southwesterly low‐level flow transported abundant moisture from the BoB to the northern SCS. Besides, the diabatic heating related to TC convection stimulated an anticyclonic anomaly in the upper troposphere over the southern Tibetan Plateau, which was conducive to the enhancement and expansion of the South Asian high (SAH) over the Indo‐China Peninsula. The stronger easterly outflows from the eastern periphery of the SAH overlapped with low‐level water vapor convergence over the northern SCS, enhancing the development of monsoon convection. Thus, more condensation heating warmed the tropospheric atmosphere and reversed the meridional temperature gradient over the SCS, implying the SCSSM onset. [ABSTRACT FROM AUTHOR]

A non-motile, Gram-staining-negative, orange-pigmented bacterium called herbae pc1-10T was discovered in Tibet in the soil around Pyrola calliantha H. Andres' roots. The isolate thrived in the temperature range of 10–30 °C (optimal, 25 °C), pH range of 5.0–9.0 (optimum, pH = 6.0), and the NaCl concentration range of 0–1.8% (optimal, 0%). The DNA G+C content of the novel strain was 37.94 mol%. It showed the function of dissolving organophosphorus, acquiring iron from the environment by siderophore and producing indole acetic acid. Moreover, the genome of strain herbae pc1-10T harbors two antibiotic resistance genes (IND-4 and AdeF) encoding a β-lactamase, and the membrane fusion protein of the multidrug efflux complex AdeFGH; antibiotic-resistance-related proteins were detected using the Shotgun proteomics technology. The OrthoANIu values between strains Chryseobacterium herbae pc1-10T; Chryseobacterium oleae CT348T; Chryseobacterium kwangjuense KJ1R5T; and Chryseobacterium vrystaatense R-23566T were 90.94%, 82.96%, and 85.19%, respectively. The in silico DDH values between strains herbae pc1-10T; C. oleae CT348T; C. kwangjuense KJ1R5T; and C. vrystaatense R-23566T were 41.7%, 26.6%, and 29.7%, respectively. Chryseobacterium oleae, Chryseobacterium vrystaatense, and Chryseobacterium kwangjuense, which had 16S rRNA gene sequence similarity scores of 97.80%, 97.52%, and 96.75%, respectively, were its closest phylogenetic relatives. Chryseobacterium herbae sp. nov. is proposed as the designation for the strain herbae pc1-10T (=GDMCC 1.3255 = JCM 35711), which represented a type species based on genotypic and morphological characteristics. This study provides deep knowledge of a Chryseobacterium herbae characteristic description and urges the need for further genomic studies on microorganisms living in alpine ecosystems, especially around medicinal plants. [ABSTRACT FROM AUTHOR]

Understanding cloud distribution over lakes is crucial to determine input radiation and precipitation for lake thermal and water balance processes. Based on Himawari‐8 satellite observation and Weather Research and Forecasting model results, this study examines the influences of lakes on daytime cloud cover during warm seasons over the Tibetan Plateau (TP), which is home to thousands of lakes. Observation shows the existence of cloud holes and narrow cloud rings around the lakes, that is, fewer clouds over the lakes and more clouds along the shoreline, which has rarely been reported and is considered typical to TP by comparison with lakes outside of TP. The threshold size of lakes that can produce the shoreline cloud ring is identified to be about 300 km2, as a conservative estimate. We further highlight the importance of atmosphere advection/background wind in the formation of lake‐associated clouds. Lake breeze forms under weak background winds and the downdraft branch inhibits cloud formation over the lakes; while the updraft branch causes convection to form clouds over lakeshores. However, strong background winds do not favor lake breeze formation, changing cloud distribution over the lakes. Fewer clouds are also found in the downwind regions, and this influence is at a distance comparable to the lake scale. Due to fewer clouds over lakes, shortwave radiation is significantly larger (∼100 W/m2) and longwave radiation is smaller (∼a few W/m2) than that of the further land region. Therefore, the above observational facts provide a new perspective to advance the understanding of lake‐air interactions. Plain Language Summary: There are lots of lakes over the Tibetan Plateau (TP), but the influence of these lakes on cloud during warm seasons remain unclear. Satellite data shows the existence of cloud holes and narrow cloud rings around the lakes, that is, fewer clouds over the lakes and more clouds along the shoreline, which has rarely been reported before. Simulation results demonstrate that the lake breeze accounts for this phenomenon: air descends over the lake, which inhibits cloud formation, while ascending branch over the shoreline favors cloud formation. Lakes over 300 km2 can yield these cloud influences, so this area is thought as the threshold area that lakes can have influence on atmosphere. Clouds in the downwind regions are also fewer under the influence of background wind, and this influencing distance is almost equal to the lake scale itself. Due to less block by clouds, solar radiation is much higher over the lake than surrounding land, but downward longwave radiation is a little lower because of less emission from the cloud bottom, resulting an increase of net radiation in total at the lake surface. The conclusions of this study can help understand energy and hydrology processes of lakes better over the TP. Key Points: Evident "cloud holes" and "cloud rings" are found for lakes over the Tibetan Plateau, which are mainly induced by lake breezeClouds in the downwind regions are also fewer due to atmosphere advection; this distance is almost equal to the size of the lake itselfFewer clouds over the lake increase the net radiation mainly due to much higher downward shortwave radiation [ABSTRACT FROM AUTHOR]

Since the continental collision between the Indian and Eurasian plates began about 50 Ma ago, southeastern Tibet (SET) has undergone complex tectonic deformation. In this study, we investigate fine scale structural features of the crustal and upper mantle depths (<250 km) beneath SET, which hold important clues to understanding the dynamic processes related to this collision. A 3D shear velocity model is constructed through jointly inverting Rayleigh wave phase velocity and teleseismic body wave data from more than 650 stations. Our 3D model identifies three independent low‐velocity zones (LVZs) in the mid‐lower crust with unprecedented details. More specifically, we observe a prominent LVZ beneath the North Chuan‐Dian Block, which is well separated from another LVZ beneath the Tengchong volcano in the south. This LVZ beneath the volcano represents a focused magma reservoir in the crust whose origin is potentially linked to the mantle upwelling associated with the eastward subduction of the Indian plate. The third LVZ, observed around the Xiaojiang Fault, likely represents a separated and mechanically weak layer in the mid‐lower crust due to the combined effects of regional crustal thickening under the southeastward plateau expansion, mantle upwelling, and shear heating of strike‐slip faults. In the upper mantle, we observe strong velocity reductions both in localized areas beneath the Tibetan Plateau and the broad region south of 26°N. These low velocity anomalies are sitting above high velocity anomalies at deeper depths, suggesting their association with lithospheric thickening and delamination processes. Plain Language Summary: Southeastern Tibet (SET) has undergone complex geological evolution due to the plate collision. To better understand the related dynamic processes, we present a high‐resolution 3D S‐wave velocity model from the earth surface to the depth of 250 km by using surface wave and body wave data. Our model shows three independent crustal low‐velocity zones (LVZs). Especially, the one beneath the Tibetan Plateau is seen to be well separated from the one beneath the Tengchong volcano which represents the hot magma upwelling related to the eastward subduction of the Indian plate. In addition, another LVZ around the Xiaojiang Fault probably represents a separated and mechanically weak layer that is attributed to the regional crustal thickening under the southeastward plateau expansion, mantle upwelling, and shear heating of strike‐slip faults. In the upper mantle, we observe strong velocity reductions both in localized areas beneath the Tibetan Plateau and the broad region south of 26°N. Many of these low velocity anomalies are sitting above high velocity anomalies at deeper depths, suggesting their origin of lithospheric thickening and delamination processes. Key Points: A 3D velocity model of SE Tibet is obtained via a joint inversion of surface wave phase velocity and teleseismic body wave dataOur model reveals spatial distributions of three isolated mid‐lower crustal low‐velocity zones with unprecedent detailsBroad low velocities in the upper mantle imply mantle upwelling related to the lithospheric delamination and slab subduction [ABSTRACT FROM AUTHOR]

The exports of carbon and nitrogen with water flowing in the headwater streams could be important components of material mitigation in forest ecosystems. Plant debris is a major source of dissolved organic matter for headwater streams, but few studies have investigated the differences between the impacts of woody debris and non‐woody debris inputs on headwater streams in terms of carbon and nitrogen exports. Here, we assessed the effects of plant debris (i.e., woody debris, non‐woody debris and mixed debris) on the concentrations and exports of dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) in the headwater streams of an alpine forest on the eastern Tibetan Plateau. Woody and non‐woody debris only weakly affected the DOC and TDN concentrations in the headwater streams. Compared with those in the reference stream excluding plant debris, woody debris increased the exports of DOC and TDN by 19% and 13%, whereas non‐woody debris decreased the exports of DOC and TDN by 22% and 25%, respectively. However, when fall approached, the role of non‐woody debris reversed to enhance the stream‐water exports of DOC and TDN. The effect of non‐woody debris during the fall season differed from that during the overall growing season, indicating that restricting non‐woody debris inputs might improve the ability of the stream to retain forest carbon and nitrogen. Notwithstanding the relatively limited experimental period, this work revealed the critical importance of plant debris for carbon and nutrients within water conservation regions like alpine forests. [ABSTRACT FROM AUTHOR]

Litter decomposition is a key pathway of metal cycling in terrestrial ecosystems, yet little is known about the dynamics of metals in decomposing roots. A two-year decomposition experiment was conducted to investigate the temporal dynamics of nine metals (Ca, K, Mg, Fe, Al, Mn, Cr, Cu, and Pb) in decomposing roots of three diameter classes (0–2 mm, 2–5 mm, and 5–10 mm) in two subalpine coniferous tree species (Picea asperata and Abies faxoniana) on the eastern Tibetan Plateau of China. Regardless of tree species and root diameters, macro metals (Ca, K, and Mg) and Cu often released over the experimental period and their remaining were 87.7%, 12.5%, 69.4%, and 47.98%, respectively. However, trace metals (Fe, Al, Mn, Cr, and Pb) generally accumulated during the decomposition process and their remaining were 159.6%, 121.5%, 196.4%, 119.6%, and 124.3%, respectively. The concentrations of Ca, K, Mg, Fe, and Al often decreased with increasing root diameters over the experimental period. For Picea asperata, the Ca, K, Fe, and Pb remaining were higher in the 5–10 mm than 0–5 mm roots, but contrasting trends were found for Mg, Mn, Cr, and Cu. For Abies faxoniana, the 5–10 mm roots had lower macronutrients (Ca, K, and Mg) but higher trace metals (Fe, Al, Mn, Cr, Cu, and Pb) remaining compared to 0–5 mm roots. Taken together, root diameter had pronounced influences on metal dynamics, depending on metallic properties, initial root quality, and/or decomposition period. Root initial chemistry (e.g., C, Mn and lignin) were significantly correlated with the metal remaining during the decomposition. Our findings address the importance of root diameter in understanding metal cycling via root decomposition pathways in forest ecosystems. [ABSTRACT FROM AUTHOR]

Continued climate warming and precipitation fluctuations are expected to further affect aboveground net primary productivity (ANPP) across alpine grasslands, with associated implications for ecosystem functions. The spatial and temporal variability of ANPP in Tibetan Plateau (TP) grasslands and its response to temperature and precipitation were investigated in this study, based on the ANPP estimated by means of ensemble analysis of multiple machine learning models. First, the response of the spatial distribution of ANPP to variations in the precipitation gradient was nonlinear and showed an S-shaped growth pattern, which could be divided into four stages (stationary, rapid growth, slower growth, and saturation) corresponding to arid (mean annual precipitation (MAP) < 250 mm), semiarid (250 mm < MAP < 450 mm), semihumid (450 mm < MAP < 650 mm) and humid (MAP > 650 mm) precipitation regimes, respectively. Second, regional precipitation regimes affected the sensitivity of ANPP's interannual variability to temperature and precipitation; ANPP is more sensitive to temperature in wetter areas than in dryer areas of the TP region. The results of our study suggest that in the region of Tibetan Plateau, the response of grassland ANPP variation to climate was constrained by the background precipitation regimes. [ABSTRACT FROM AUTHOR]

Litter humification plays a crucial role in organic matter formation and soil carbon sequestration in forest ecosystems. However, how forest gap formation and gap size variation affect the litter humification process remains poorly understood. An eight-year in situ decomposition experiment was conducted to evaluate humus accumulation (humic substances, humic and fulvic acid), humification degrees, humification ratios and optical properties (ΔlogK, E4/E6 and A600/C) of Minjiang fir (Abies faxoniana Rehder & E.H.Wilson) twig litter in four gap size treatments in an alpine primitive forest on the eastern Tibetan Plateau, including (1) closed canopies, (2) small gaps (38–46 m2 in size), (3) medium gaps (153–176 m2 in size),and (4) large gaps (255–290 m2 in size). The results indicated that the accumulation of humic substances and humic acid in the closed canopies was significantly higher than that in the large gaps during the first two years of decomposition. After eight years of decomposition, there were significant differences in the humic substance accumulations and the values of ΔlogK and A600/C among the different gap sizes. Furthermore, twig litter was humified in the first 2 years of incubation, and the net accumulation of humic substances was ranged from −23.46% to −44.04% of the initial level at the end of the experiment. The newly accumulated humus was young (mature (type Rp) humus) and transformed to mature (type A) humus after 4–6 years of decomposition. Partial least squares (PLS) suggested that gap-induced variations in twig litter chemistry (i.e., contents of cellulose, lignin, nitrogen (N) and phosphorus (P), and the ratios of C/N N/P) mainly drove the process of twig litter humification. Our results presented here denote that the formation of forest gaps retard twig litter humification process, which might be detrimental to carbon sequestration in the alpine forest ecosystems. [ABSTRACT FROM AUTHOR]

Trends of precipitation over the Tibetan Plateau (TP) are characterized by a north‐south dipole pattern, and the role of local mesoscale systems, TP vortices (TPVs), remains ambiguous. This work reports that the north‐south dipole pattern trends in the TPVs‐associated precipitation have experienced an interdecadal shift in the last two decades, that is, increases in northern TP and decreases in southern TP first and then varies opposite trends, which greatly contributes to the similar interdecadal shift in TP precipitation trends. Furthermore, the causes of changes in TPV frequency are explored from the perspective of lower troposphere conditions. We find that the lower‐level winds, that is, zonal winds over the TP and meridional winds across the northwestern TP boundary, are responsible for the regionally different variations in TPV frequency. The variations in Indian Ocean Dipole are suggested to contribute to the changes in lower‐level winds over the TP. Plain Language Summary: Precipitation over the Tibetan Plateau (TP) significantly affect local and downstream water resources, which generally presents dipole pattern trends, that is, opposite precipitation trends in the northern TP (NTP) and in southern TP (STP). However, the physical processes of the variations in TP precipitation, especially the roles of local mesoscale systems, TP vortices (TPVs), are not yet clear. In this work, dipole pattern variations are found in TPVs‐associated precipitation, which experienced an interdecadal shift in the last two decades, that is, increases in NTP and decreases in STP first and then varies opposite trends. The interdecadal shift in the TPVs‐associated precipitation trends greatly contributes to the interdecadal shift in the TP precipitation trends. Furthermore, the causes of variations in TPV frequency are explored, and find that the changes in zonal winds over the TP and meridional winds across the northwestern TP boundary are closely related to the regionally different variations in TPV frequency. Subsequently, the changes in the sea surface temperature of India Ocean are demonstrated to be responsible for the wind variations. Key Points: North‐south dipole pattern precipitation trends over the Tibetan Plateau (TP) have experienced an interdecadal shift in the last two decadesChanges in TP vortices (TPVs) contribute to the interdecadal shift in the TP precipitation trend patternSea surface temperature of India Ocean is responsible for variations in lower‐level winds, prompting changes in TPVs [ABSTRACT FROM AUTHOR]

The Anninghe-Zemuhe-Xiaojiang fault zone (AZXFZ) is an important boundary fault zone on the southeastern margin of the Tibetan Plateau, with frequent strong earthquakes. Previous studies have imaged widespread low-velocity zones in this area. However, there are still many disputes on the connectivity and genesis of the low-velocity zones. In this study, we obtain the Rayleigh wave phase velocity dispersion curves at 4–25-s periods using observations from 378 broadband stations located near the AZXFZ. The new 3D S-wave velocity model has a lateral resolution of about 30 km in 0–35-km depth and is obtained by direct inversion of surface wave dispersion data. The new results clearly image two low-velocity zones and a high-velocity zone in the middle crust of the study region. The low-velocity zone on the western side of the Lijiang-Xiaojinhe fault is related to the eastward flow of crustal material and the movement of the left lateral strike-slip faults in the Tibetan Plateau, while the low-velocity anomaly distributed along the Daliangshan fault and Xiaojiang fault is the superimposition effect of shear heating of the faults and upwelling of mantle material. The uplift of Gongga Shan is a combination of the continuous accumulation of crustal material in the middle and lower crust of the southeastern margin of the Tibetan Plateau as well as the bending and compression of the Sichuan-Yunnan Block and the Xianshuihe-Anninghe fault zone. [ABSTRACT FROM AUTHOR]

The Tibetan partridge (Perdix hodgsoniae) is a widely distributed endemic species in high-altitude areas across the Tibetan Plateau where the hypoxia, lower temperature and high ultraviolet radiation are pivotal factors influencing survival. However, the underlying genetic adaptation of the Tibetan partridge to extreme environments remains uncertain due to limited genomic resources. Similarly, the phylogenetic position of Perdix within Phasianidae remains controversial due to lacking information. Consequently, we de novo assembled and annotated the whole genome of the Tibetan partridge. The genome size was 1.15 Gb with contig N50 of 3.70 Mb. A total of 202.30 Mb (17.61%) repetitive elements and 445,876 perfect microsatellites were identified. A total of 16,845 functionally annotated protein-coding genes were identified in the Tibetan partridge. Genomic phylogenetic analysis across 30 Galliformes species indicated a close relationship between Perdix and typical pheasants composed of Chrysolophus , Symaticus , Phasianus , Crossopilon , and Lophura. However, the phylogenetic relationship of (Perdix + (Chrysolophus + (Syrmaticus + other pheasants))) was different from those of (Perdix + (Syrmaticus + (Chrysolophus + other pheasants))) in previous studies. Comparative genomic results identified NFKB1 and CREBBP positively selected genes related to hypoxia with 3 and 2 Tibetan partridge-specific missense mutations, respectively. Expanded gene families were mainly associated with energy metabolism and steroid hydroxylase activity, meanwhile, contracted gene families were mainly related to immunity and olfactory perception. Our genomic data considerably contribute to the phylogeny of Perdix and the underlying adaptation strategies of the Tibetan partridge to a high-altitude environment. [ABSTRACT FROM AUTHOR]

Identifying the factors influencing wetland variations is crucial for understanding the relationship of climate change with wetland conservation and management. The wetland distribution is associated with multiple variables, and the interactions among these variables are complex. In this study, we aim to explore an interpretable and quantitative analysis of factors related to wetland spatiotemporal variations on the Tibetan Plateau (TP). By combining SHapley Additive exPlanations with a spatially stratified heterogeneity model, we propose a locally explained stratified heterogeneity (LESH) model that well reveals the effects of multiple variable interactions on the spatiotemporal variations of wetlands. The results show that topographic variables are the most important variables related to the spatial distribution of wetlands on the TP, and climatic variables are the most relevant factors for the increase in the wetland area on the TP from 2015 to 2019. In addition, the interactions among multiple variables strongly influence wetlands on the TP. Among them, when other geographic variables interact with the evaporation variable, its explanatory power on wetland distribution is significantly increased. Knowledge of wetland distribution determinants can help us understand the evolution of wetlands and the impacts of climate change on wetland variations. [ABSTRACT FROM AUTHOR]

Qinghai-Tibet Plateau lakes are important carriers of water resources in the 'Asian's Water Tower', and it is of great significance to grasp the spatial distribution of plateau lakes for the climate, ecological environment, and regional water cycle. However, the differences in spatial-spectral characteristics of various types of plateau lakes, and the complex background information of plateau both influence the extraction effect of lakes. Therefore, it is a great challenge to completely and effectively extract plateau lakes. In this study, we proposed a multiscale contextual information aggregation network, termed MSCANet, to automatically extract Plateau lake regions. It consists of three main components: a multiscale lake feature encoder, a feature decoder, and a Multicore Pyramid Pooling Module (MPPM). The multiscale lake feature encoder suppressed noise interference to capture multiscale spatial-spectral information from heterogeneous scenes. The MPPM module aggregated the contextual information of various lakes globally. We applied the MSCANet to the lake extraction of the Qinghai-Tibet Plateau based on Google data; additionally, comparative experiments showed that the MSCANet proposed had obvious improvement in lake detection accuracy and morphological integrity. Finally, we transferred the pre-trained optimal model to the Landsat-8 and Sentinel-2A dataset to verify the generalization of the MSCANet. [ABSTRACT FROM AUTHOR]

Plant pathogens are often hypothesized to promote species coexistence by generating conspecific negative density dependence (CNDD). However, the relative importance of fungal versus oomycete pathogens in maintaining plant species coexistence and community composition remains unresolved, despite their recognized effects on plant performance. Here, we use fungicide application to investigate how fungal versus oomycete pathogens affect plant species coexistence in an alpine meadow. We found that the severity of foliar fungal disease was density‐dependent at both intra‐ and interspecific levels. Fungal pathogen‐exclusion treatment successfully decreased the severity of foliar fungal diseases, with no detectable effects on root colonization by arbuscular mycorrhizal fungi or on soil chemical properties. Fungal pathogens were important factors shaping CNDD across 25 coexisting plant species. Exclusion of fungal pathogens significantly reduced plant species richness and Shannon's evenness. Treatments that excluded fungal pathogens also led to significant shifts in plant community composition toward more Poaceae and Cyperaceae. These results indicate that fungal pathogens, especially those affecting aboveground plant parts, may play a larger role in maintaining species coexistence and shaping community composition than has been previously recognized. [ABSTRACT FROM AUTHOR]

The Regional Climate Model Version 4 (RegCM4) with the conventional plane‐parallel radiative transfer scheme severely overestimates the summer precipitation over the Tibetan Plateau (TP) due to the excessive surface heat source, which results from the poor representation of the sub‐grid terrain‐related radiation processes. To realistically describe the surface sub‐grid radiation process in the RegCM4, a 3‐dimensional sub‐grid terrain solar radiative effect (3DSTSRE) parameterization scheme is implemented into the RegCM4 to improve the original plane‐parallel radiative transfer scheme. Results show that adopting the 3DSTSRE scheme in RegCM4 can significantly reduce the summer (June–August) wet bias over the TP produced by the model with the plane‐parallel radiative transfer scheme. Mechanism analysis indicates that the 3DSTSRE scheme largely improves the description of the TP surface energy balance in the RegCM4 by reducing the positive bias of downward surface solar radiation (DSSR). The reduced DSSR leads to the weakened surface heat source and cooler near‐surface air over the TP. Consequently, the local atmospheric circulation adapts to the temperature field as the low‐level anti‐cyclonic (high‐level cyclonic) anomaly over the TP. The adjustment of the temperature and wind field attenuates the water vapor transport, enhances the low‐level atmospheric stability, inhibits the updraft motion, and eventually reduces the rainfall over TP. Although the 3DSTSRE improves the DSSR simulation only during daytime, the precipitation simulation is also improved at nighttime, which is fundamentally attributed to the maintenance of the cooled atmosphere throughout the daytime and nighttime. Key Points: A 3‐dimensional sub‐grid terrain solar radiative effect (3DSTSRE) scheme has been successfully implemented into the RegCM4 modelThe surface solar radiation flux and heat balance over the Tibetan Plateau in summer can be clearly improved by RegCM4 with the 3DSTSREThe wet biases of RegCM4 over the regions with complex terrain in Tibetan Plateau can be largely reduced by adopting the 3DSTSRE scheme [ABSTRACT FROM AUTHOR]

The evolutions of climate‐sensitive lakes on the Tibetan Plateau's endorheic basin exhibited lake shrinkage before the mid‐1990s, but widespread and rapid lake expansions ever since. However, the quantitative contribution of glacier meltwater to lake changes, and the exact mechanisms behind its dominant drivers remain elusive. Here, a comprehensive examination of glacier mass balance since ∼1975 reveals that excess glacier meltwater compensated for net lake volume loss by 21% ± 5% during its contraction period 1975–1995, whereas promoted net volume gain by 9% ± 1% during expansion period 1995–2020 and by 17% ± 2% over the entire period 1975–2020. Further analyses reveal that the interdecadal variations of sea surface temperatures in the Atlantic, Pacific, and Indian Oceans favor a net moisture inflow to the Tibetan Plateau, leading to increased precipitation since 1995 relative to 1970s–1995, which effectively elucidates the climatic process causing rapid lake volume expansion in the endorheic basin. Plain Language Summary: Most of the lakes over the Tibetan Plateau are located in its endorheic basin in the Inner Plateau, forming a 700,000 km2 landlocked drainage area with an average elevation of over 4,000 m above sea level. An updated survey using comprehensive historic satellite images reveals a change in the trends of the number of lakes formed, their area, lake level, and volume over the past half a century, 1975–2020. The number and area of the lakes shrunk in 1975–1995, followed by an expansion in 1995–2020. Here, we elucidate the origin of this climatic change and conclude that excess glacier meltwater contributed to lake water balance by 21% during the lake contraction period 1975–1995. During the lake rapid expansion period of 1995–2020, mountain glaciers wasted at twice the rate during the earlier period; however, the contribution fraction remains smaller at 9%. The pattern of precipitation was the dominant driver of this multidecadal trajectory in lake change trends. The increases in precipitation since 1995 relative to 1970s−1995 was mainly induced by increased net moisture, which was attributable to interdecadal variations of sea surface temperature in the Atlantic, Pacific, and Indian Oceans. Key Points: Glacier melt compensated for net lake volume loss by 21% in 1975–1995 and promoted net lake volume gain by 9% in 1995–2020Glacier meltwater contributing to lake water gain mainly occurred in the southern Inner Tibetan PlateauTeleconnection of interdecadal sea surface temperature changes in three oceans was associated with increased precipitation and lake expansion [ABSTRACT FROM AUTHOR]

To reduce the uncertainty of cloud feedback, models should prioritize the evaluation of cloud response to surface warming. Using International Satellite Cloud Climatology Project‐H data sets, we quantified the cloud fraction response of different cloud types to surface warming in the Tibetan Plateau (TP) and examined the performance of Coupled Model Intercomparison Project Phase 6 models in reproducing cloud response. Results showed multimodel ensemble mean (MEM) exhibited a similar pattern of total cloud fraction response with the observation but severely underestimated it over the western TP. MEM also obviously underestimated cloud fraction of optically thin cirrus (bias >15%) and had a wrong trend of −0.02% 10a−1 against observed +2.44% 10a−1. Moreover, models failed to reproduce extensive negative response of optically thick clouds and exhibited significant underestimation for the negative response of optically thick but lower‐top clouds. Especially, models even simulated an opposite response with International Satellite Cloud Climatology Project for optically thin but lower‐top cloud (bias hit −0.4% K−1). Plain Language Summary: To reduce the uncertainty in cloud feedback, knowledge about the response of cloud fraction (as the first‐order variable impacting downwelling shortwave radiation flux) to the surface warming is an important yet poorly understood process, especially over the Tibetan Plateau (TP). This study utilized 31 years of cloud top pressure (PC)‐cloud optical thickness (PC‐τ) histograms from the International Satellite Cloud Climatology Project‐H data set to characterize cloud fraction response for different cloud types and comprehensively evaluate the performance of Coupled Model Intercomparison Project Phase 6 models in reproducing cloud response over the TP. Although multimodel ensemble mean (MEM) showed similar distribution of total cloud fraction response with observation, cloud response over the western TP was significantly underestimated. For the most frequent but less simulated optically thin high cirrus, the MEM produced consistent cloud response with the observation mainly due to the offsetting effect of regional cloud response bias. In addition, we found that optically thick but lower‐top clouds (or thin high cirrus) significantly declined (or increased) with surface warming, especially under an unstable state. Nonetheless, MEM significantly underestimated an extensive negative cloud response of optically thick clouds, especially at low‐level atmosphere. These new insights will help models reduce the uncertainty in future climate projections caused by cloud feedback. Key Points: Even if biases are partly offset, Coupled Model Intercomparison Project Phase 6 models still obviously underestimate total cloud fraction response in the western Tibetan PlateauFor more frequent but less simulated thin cirrus, models show consistent response with the observation mainly due to offsetting of the regional biasModels severely underestimate the negative response of low‐level thick clouds and invert the positive response of low‐level thin clouds [ABSTRACT FROM AUTHOR]

The north‐eastward extrusion of the Tibetan Plateau has always been under debate. The arcuate tectonic belt is located at the north‐east margin of the Tibetan Plateau and bears crucial information about the tectonic and geomorphic evolution of north‐east Tibetan Plateau. Combined with sedimentary sequence, detrital zircon U–Pb geochronology, and heavy mineral combinations, significant provenance transformation can be determined both in the south‐west and north‐east of the arcuate tectonic belt during the Eocene to Miocene. The far‐field effect of north‐eastward extrusion of the Tibetan Plateau first arrived at the south‐west of the arcuate tectonic belt during the Miocene and resulted in the angular unconformity between the Eocene Qingshuiying period and Miocene Zhangenbao Formation. Then the regional exhumation spread from south‐west to north‐east across the arcuate tectonic belt, and sedimentary hiatus developed between the Miocene Zhangenbao period and Pliocene Ganhegou period. Therefore, tectonic uplift and mountain building of the arcuate tectonic belt expanded north‐eastward during the Eogene to Neogene. This research shed new insights on the north‐eastward extrusion of the Tibetan Plateau from the coupling relationship between basin and range. [ABSTRACT FROM AUTHOR]

High altitude areas play an essential role in the global climate system, and their fragile ecosystems sensitively respond to climate change and human activities. An improved understanding of the influences of multiple factors on the spatiotemporal dynamics of vegetation is needed. This study aimed to understand further the impacts of climate, geography, and human on vegetation and disentangle the contributions of climate and humans to vegetation changes using the MOD13Q1 enhanced vegetation index (EVI, 2000–2019). Greening was detected for 70% of the Tibetan Plateau under increased warming and wetting in the 21st century. A rise in temperature of up to 0.66 ± 0.49°C decade−1 occurred over 2/3 of the Tibetan Plateau, while precipitation increased slightly. In particular, significant greening covered 1/4 of the Tibetan Plateau and occurred within the steppe and desert on the northern due to wetting and ecological protection. Browning depended on urbanization, overgrazing, and lake expansion in 1.9% of the total area. Orbicular browning around lakes accounted for 18.4% of significant browning, and significant browning trends were also detected in densely populated cities situated at low‐altitude and flat areas. The EVI was more strongly positively correlated with the annual mean minimum temperature than the annual mean temperature and maximum temperature and was sensitive to extreme low precipitation events. Residual analysis showed that the relative contribution of climate change was 34%, and that of human activities was 66%. A comprehensive description of the vegetation changes on the Tibetan Plateau will help humans to cope with climate change and ecosystem evolution in high altitude. [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]

Palaeoglacier modelling is an important approach for reconstructing the palaeoclimate. The timing of glaciations in the central part of the Gangdise Mountains has been constrained previously, but the palaeoclimate remains unclear. In this paper, the palaeo-temperature and precipitation of the early marine isotope stage (MIS) 2, the Last Glacial Maximum (LGM), and the early Holocene were reconstructed using coupled mass balance and ice flow models. The results show that a series of temperature changes (ΔT) and precipitation factors (Fp) resulted in optimum palaeoglacial extents. The modelled palaeoglaciers during the early MIS 2, the LGM, and the early Holocene cover areas of ~18.1 km2, ~17.4 km2, and ~16.3 km2, respectively, with ice volumes of ~2.18 km3, ~1.99 km3, and ~1.95 km3, respectively. Previous studies on ice cores, pollen samples, and lake sediments were referenced to narrow the range of palaeo-temperatures and precipitations. The reconstructed temperatures during the early MIS 2, LGM, and early Holocene were constrained to 2.4–2.9 °C, 2.15–3.05 °C, and 0.95–1.5 °C lower than today, respectively. Their precipitation levels were 60–80%, 50–80%, and 100–150% of the present-day level, respectively. [ABSTRACT FROM AUTHOR]

Plant leaf stoichiometry reflects its adaptation to the environment. Leaf stoichiometry variations across different environments have been extensively studied in grassland plants, but little is known about intraspecific leaf stoichiometry, especially for widely distributed species, such as Stellera chamaejasme L. We present the first study on the leaf stoichiometry of S. chamaejasme and evaluate its relationships with environmental variables. S. chamaejasme leaf and soil samples from 29 invaded sites in the two plateaus of distinct environments [the Inner Mongolian Plateau (IM) and Qinghai-Tibet Plateau (QT)] in Northern China were collected. Leaf C, N, P, and K and their stoichiometric ratios, and soil physicochemical properties were determined and compared with climate information from each sampling site. The results showed that mean leaf C, N, P, and K concentrations were 498.60, 19.95, 2.15, and 6.57 g kg−1; the average C:N, C:P, N:P, N:K and K:P ratios were 25.20, 245.57, 9.81, 3.13, and 3.21, respectively. The N:P:K-ratios in S. chamaejasme leaf might imply that its growth is restricted by K- or K+N. Moreover, the soil physicochemical properties in the S. chamaejasme-infested areas varied remarkably, and few significant correlations between S. chamaejasme leaf ecological stoichiometry and soil physicochemical properties were observed. These indicate the nutrient concentrations and stoichiometry of S. chamaejasme tend to be insensitive to variations in the soil nutrient availability, resulting in their broad distributions in China's grasslands. Besides, different homeostasis strength of the C, N, K, and their ratios in S. chamaejasme leaves across all sites were observed, which means S. chamaejasme could be more conservative in their use of nutrients improving their adaptation to diverse conditions. Moreover, the leaf C and N contents of S. chamaejasm were unaffected by any climate factors. However, the correlation between leaf P content and climate factors was significant only in IM, while the leaf K happened to be significant in QT. Besides, MAP or MAT contribution was stronger in the leaf elements than soil by using mixed effects models, which illustrated once more the relatively weak effect of the soil physicochemical properties on the leaf elements. Finally, partial least squares path modeling suggested that leaf P or K contents were affected by different mechanisms in QT and IM regions, suggesting that S. chamaejasme can adapt to changing environments by adjusting its relationships with the climate or soil factors to improve its survival opportunities in degraded grasslands. [ABSTRACT FROM AUTHOR]

The Xizang plateau frog, N. parkeri (Anura: Dicroglossidae), is endemic to the Tibetan Plateau, ranging from 2,850 to 5,100 m above sea level. The present study explores physiological and biochemical adaptations to high altitude in this species with a particular emphasis on parameters of hematology, oxidative stress, and antioxidant defense in adult and juvenile N. parkeri collected from high (4,600 m a.s.l) and low (3,400m a.s.l) altitudes. Hematological results showed that hemoglobin concentration ([Hb]), hematocrit (Hct), and red blood cell (RBC) counts were significantly higher in high-altitude N. parkeri. Highaltitude juveniles had lower RBC sizes than low-altitude juveniles. Higher levels of GSH and GSSG were indicated only in juveniles from high altitude, not in adults. High-altitude individuals also showed lower oxidative damage, assessed as malondialdehyde (MDA) and carbonyl groups (CG) in the liver. High-altitude adults also showed higher activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), and glutathione-S-transferase (GST) as well as total antioxidant capacity (T-AOC) in the liver as compared to low-altitude adults. Moreover, higher GPX activity and T-AOC were observed in the heart and brain of high-altitude adults. Liver CAT, GPX, and T-AOC showed significant increases in high-altitude juveniles. Vitamin C content was also higher in the heart of high-altitude frogs compared to low-altitude individuals. In summary, the highaltitude population of N. parkeri showed more robust hematological parameters, less oxidative damage, and stronger antioxidant defenses than the low-altitude population, all contributing to increased protection for survival in high-altitude environments. [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]

The East Kunlun Orogenic Belt (E‐KOB) of the northern Tibetan Plateau is an accretionary orogenic belt, which has experienced complicated tectonic evolutionary processes of the Proto‐ to Palaeo‐Tethys Ocean. The Muztagh‐Buqingshan‐Anemaqen ophiolitic mélange zone (MBAM) is an accretionary complex related to the northward subduction of the Tethyan Ocean. Numerous intrusions outcropped in MBAM have witnessed the long‐term subduction‐accretionary process and thus site the key to comprehending the tectonic evolution of the E‐KOB, as well as the Tethyan Ocean. In this study, petrological, geochronological, and geochemical studies of the Marzheng diorites in the MBAM were carried out to explore the Early Palaeozoic tectonic evolution of the E‐KOB. Zircon U–Pb dating analysis suggests that the diorites were formed in the Early Ordovician at ca. 470 Ma. Furthermore, the εHf(t) values (5.3–14.1), Mg# values (39.7–51.2), and Nb/Ta (12.8–14.8), Zr/Hf (33.8–44.8), and Lu/Yb (0.15–0.16) ratios are generally close to those of depleted mantle‐derived rocks and the diorites were originated from a depleted asthenosphere mantle source. In addition, these diorites are characterized by enriched light rare earth elements (LREEs) (La and Nd) and depleted high‐field‐strength elements (HFSEs) (Nb, Ta, P, and Ti), similar to the fingerprints of arc‐related gabbroic‐dioritic rocks. This is also consistent with their high H2Omelt (6.0–8.3%) and oxygen fugacity (logfO2 = −14.3 to −13.5) features, indicating that they were formed in a subduction‐related setting. Our new investigations suggest that the Proto‐Tethys Ocean in the East Kunlun was still actively subducting northward during the Early Ordovician. [ABSTRACT FROM AUTHOR]

Palaeoflood records have provided the extended perspective required to understand linkages between extreme floods and climate variability. During our palaeo‐hydrological investigations, two units of palaeoflood slackwater deposits (SWD) were found on the river banks in the Maqu‐Oula reach along the mainstream of the Yellow River on the northeast (NE) Tibetan Plateau. A series of samples were taken from the sediment profiles at Taiwuruo (TWR) and Daerqiong (DEQ) sites for laboratory analysis. Grain‐size distribution and micro‐morphological characteristics of quartz grains indicate that these well‐sorted SWD units were derived from the suspended sediment load in floodwater. They have recorded two episodes of overbank flooding in the Yellow River source area. Using the optically stimulated luminescence (OSL) dating technique, the first episode of overbank flooding was dated to 13.6–13.0 ka and correlated with the Bølling–Allerød warm interval of the last deglaciation. The second episode occurred at 11.0–10.0 ka, that is, the early Holocene. In a warm‐humid climate, these overbank flooding episodes may have resulted from the accelerated melting of mountain glaciers and snow over the headwaters of the alpine and subalpine regions on the NE Tibetan Plateau. These results are important in facilitating an in‐depth understanding of the hydro‐climatic response of the Tibetan Plateau to global climate warming occurring presently. [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]

Assessment of soil organic carbon (SOC) concentration in high‐altitude shrublands is essential for understanding C dynamics in terrestrial ecosystems. Hence, we investigated the SOC concentration and its influencing factors using 198 soil profiles (0–100 cm) from 66 sites between 2011 and 2013 in the north‐eastern Tibetan Plateau shrublands. SOC concentration was different under different shrubland types, with SOC concentration significantly greater in the alpine shrublands relative to the desert shrublands, whereas SOC concentration showed limited increases with altitude. Both mean annual temperature (MAT) and mean annual precipitation (MAP) have positive relationships with SOC concentration, and their relationships are moderate. Compared with MAT, a correlation between MAP and variation in SOC concentration was larger. Meanwhile, with increasing soil depth, a correlation between variation in SOC concentration and climatic factors was smaller. Soil pH seems to be a robust factor that not only had a significant negative correlation with SOC, but also played an important role in regulating a correlation between climatic condition and variation in SOC concentration. Controls on variation of SOC concentration on the Tibetan Plateau help to understand soil C dynamics in terrestrial ecosystems. Highlights: SOC concentration was different under different shrubland types, whereas SOC concentration showed limited increases with altitude.Compared with MAT, a correlation between MAP and variation in SOC concentration was larger.Soil pH seems to be a robust factor that had a significant negative correlation with SOC concentrationSoil pH was also important for regulating a correlation between climatic condition and variation in SOC concentration. [ABSTRACT FROM AUTHOR]

The roles of lower-crustal flow and upper-crustal shortening on the growth of the SE Tibetan Plateau remain under debate, which calls for a knowledge about regional exhumation history. We analyzed apatite fission track ages of modern sediments from both the east and west sub-catchments along the Anninghe River, in the SE plateau. We obtained four age components, with peaks a bit younger in the east than in the west. Combing the asymmetric topography with higher relief in the east, we concluded a non-uniform exhumation pattern. The components are at the Oligocene, late-Miocene, Pliocene, and Pleistocene, mostly consistent with the timing for changes in catchment-wide erosion rates as indicated by the inverse erosion history. We concluded that, in addition to the late-Miocene lowercrustal flow and Oligocene upper-crustal shortening, the landscape in the SE plateau might also be under influences of fault strike-slip transfer and drainage network reorganization. Plain Language Summary Different models that have been proposed to explain how the topography in the SE Tibetan Plateau grows predict different histories for regional uplift and/or erosion. Lower-crust flow was suggested to drive rapid surface uplift since 10-15 Ma, while findings of earlier fault thrusting implies the effects of upper-crust shortening. To test these models, we analyzed detrital ages of sediments from both the east and west sub-catchments along the modern Anninghe River, in the SE plateau. We obtained the Oligocene, late-Miocene, Pliocene, and Pleistocene age components, all of which are with peaks a bit younger in the east than in the west. Considering that the topography is also somewhat steeper in the east, we concluded a spatially non-uniform erosion pattern since the middle Cenozoic. The four age components reveal multistage erosion processes in the Anninghe catchment and thus indicate multiple forces to drive topographic growth in the SE plateau. [ABSTRACT FROM AUTHOR]

Precipitation over the Tibetan Plateau (TP) significantly affects both the local ecology and the downstream water resources. In this study, it is found that there exists an increasing precipitation trend over the northern TP but not in the southern TP, which is interpreted from the perspective of the activities of Tibetan Plateau vortices (TPVs). In the context of recent warming over the TP, the increasing rate of genesis frequency of TPVs over the northern TP is remarkably larger than that over the southern TP, which is responsible for different precipitation trends in the northern and southern TP, respectively. That is, the most significant warming over the TP appears in the upper troposphere, which intensifies the 200 hPa westerly jet north of the TP, hereby produces more favorable conditions for the genesis of TPVs over the northern TP than over southern TP, and contributes to regional difference in precipitation trends. Plain Language Summary Precipitation over the Tibetan Plateau (TP) significantly affects the local ecology and the downstream water resources. In recent decades, significant warming trend is observed over the TP. It is found that the precipitation trends over the TP show robust regional differences in the warming context, with the causal physical process being not yet clear. Given the Tibetan Plateau vortices (TPVs) are important rainfall triggers over the TP, the regionally different precipitation trends over the TP are interpreted from the perspective of TPVs. Here, we show that warming over the TP causes regionally different increases in the genesis frequency of TPVs by modulating the upper-level westerly jet, and hereby contributes to the regional difference in precipitation trends over the TP. [ABSTRACT FROM AUTHOR]

The Mesozoic–Cenozoic Zheduo–Gongga Massif, eastern Songpan–Ganze Terrane, can provide important clues for the crustal evolution in response to syn‐ and post‐orogeny. Here, we document petrological and geochemical characteristics of Early Jurassic granites (181.0 ± 2.2 Ma) within the massif along the Xianshuihe Fault in the eastern Tibetan Plateau. The granites have high contents of SiO2, Na2O + K2O, FeOT/MgO, 10,000 × Ga/Al, REE (except Eu) and HFSE (e.g., Nb, Ta, Zr, Hf), low CaO, TiO2, P2O5 and negative Eu, Sr, and Ba anomalies. Zircon REE shows a similar pattern with the whole‐rock REE. Our new data demonstrate weakly peraluminous A‐type affinity with A/CNK >1.0 and alkali‐calcic, ferroan features. Zircon saturation temperatures and geochemical features (e.g., high SiO2 and low MgO contents, high Rb/Ba and Rb/Sr ratios) indicate that the granites resulted from high‐temperature (>800°C) partial melting of Triassic flysch rocks in relatively shallow crust (<500 MPa or <20 km). Zircon εHf(t) values range from 0.55 to 2.91 and the corresponding two‐stage TDMC are older than the neighbouring Kangding complex and Yangtze margin, implying possible contribution of mantle materials to the parent magma. Considering the tectonic events and the regional geology, the magma was generated in a post‐collisional setting, which was possibly driven by the upwelling of hot mid–lower crustal materials due to the break‐off of subducted Palaeo‐Tethys Ocean slab. Under this situation, the magma may move upwardly into the pre‐existing Xianshuihe Fault during the post‐collisional extension of the thickened crust. Thus, slab break‐off played a key role in the genesis of the Zheduo–Gongga Massif studied herein. [ABSTRACT FROM AUTHOR]

The Tibetan Plateau experienced severe aeolian desertification during the mid‐ and late 20th century, but mitigation of this aeolian desertification has occurred since 2000 despite a warming climate. The causes of aeolian desertiffication and its mitigation have been debated by scientists because of their potentially huge significance for PR China and Asia, as well as for global climate systems. Based on a review of previous studies and our own investigations, it appears that aeolian desertification from the 1970s to 2000 was caused primarily by unsustainable and irrational human activities, and its mitigation since the 2000 was mainly attributable to a warmer and wetter climate, combined with decreasing wind intensity, for the Plateau as a whole. However, the dominant factors for mitigation varied spatially. The Government's ecological protection projects have been implemented in some places with dense population, and played a key role in the mitigation in these places. The Plateau's climate will likely become warmer and wetter in the 21st century based on Coupled Model Intercomparison Project Phase 5 model simulations. If the simulation results are credible, mitigation of aeolian desertification will continue in the 21st century due to a combination of continuing grazing exclusion and rotational grazing, even without artificial revegetation. [ABSTRACT FROM AUTHOR]

As the largest inland basin in the northeastern Tibetan Plateau, Qaidam Basin has traditionally been thought of as the key region to study the Cenozoic climatic changes in the plateau; however, the information from a palaeobotanic respect is still lacking because of the paucity of the fossil plants. Fossil fruits and foliage of Ailanthus (Simaroubaceae) are reported from the Oligocene Shangganchaigou Formation in the northwestern Qaidam Basin, Qinghai Province, China. All the characters suggest that the fossil materials should be assigned to A. confucii, which is one widely distributed fossil species in the Cenozoic, regarded as the analogue of extant A. altissima. Current materials represent the first fossil record of Simaroubaceae in the northern Tibetan Plateau. Based on the climate requirements of the living A. altissima, the ranges of mean annual temperature (MAT) and mean annual precipitation (MAP) reflected by current fossils from Qaidamare 6.9–17.0°C, and 376–1,383 mm, respectively, compared with the current climate at the fossil site with MAT of −1.03°C and MAP of 60.5 mm. The results indicate that the climate conditions of the fossil site during the Early Oligocene were much warmer and more humid than that of the current. We hereby suggest the warm and moist air could approach the northwestern Qaidam and to accommodate the ecological environment in Early Oligocene. [ABSTRACT FROM AUTHOR]

In this study, we analyze the relationships between summer afternoon low cloud cover and environmental conditions over the Tibetan Plateau (TP). Using in situ measurements, satellite data, and reanalysis, and based on theoretical analysis, we find that there is stronger thermal turbulence, lower temperature, and higher frequency of low cloud formation for the same surface relative humidity over the eastern and central TP compared with eastern China. With the same sensible heat flux, decreased air density enhances buoyancy flux, which increases the planetary boundary layer height and moisture vertical transport. At the same time, with the same near‐surface relative humidity, lower temperature over the TP decreases the lifting condensation level, which increases the probability of the air parcel reaching this level. Compared to the low‐elevation region in eastern China, these two mechanisms enhance low cloud occurrence in the afternoon over the TP. Plain Language Summary: Previous studies suggested that planetary boundary layer processes play an important role in the formation of more low clouds in the afternoon over the Tibetan Plateau (TP). However, detailed mechanisms for the differences in low cloud occurrence in the afternoon over the TP versus eastern China (low‐elevation region) remain unclear. Using in situ measurements, satellite data, and reanalysis, and based on theoretical analysis, we first quantify the more frequent low cloud occurrence over the TP, and then propose two mechanisms: (i) compared to eastern China, in the afternoon over the TP, the lower near‐surface temperature results in a lower height where condensation occurs (given the same relative humidity), and (ii) the lower air density (given the same surface sensible heat flux) results in a larger buoyancy flux, leading to a deeper boundary layer. These two mechanisms work together to increase cloud formation in the afternoon over the TP. Key Points: There are more summer afternoon low clouds over the Tibetan Plateau (TP) than over eastern China as a result of two mechanismsCompared to eastern China, with the same relative humidity, lower temperature over the TP results in a lower lifting condensation levelWith the same surface sensible heat flux, lower air density over the TP results in a larger buoyancy flux and a deeper boundary layer [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]

Understanding how biotic and abiotic filters drive plant distributions is critical for informing restoration efforts of degraded lands. However, it remains unclear whether or not it is possible to develop efficient restoration strategies that are based on field investigations? Here, we conducted a field‐based investigation along a land degradation gradient on the Tibetan Plateau. Along this gradient, we compared species composition, Pianka's niche overlap, and total aboveground biomass among grasses, sedges, legumes, and forbs. We also used Faith's (1992) phylogenetic diversity index (PD) and the net relatedness index (NRI) to measure community phylogenetic patterns. To understand the effects of abiotic filtering, we measured soil pH, moisture, electrical conductivity, total soil organic carbon, microbial biomass carbon, and microbial biomass nitrogen. Our results show that grasses replaced sedges and mesoxerophytes replaced mesohydrophytes with increasing land degradation. We also found that niche overlap declined with increasing degradation intensity. Furthermore, grass biomass increased, while sedges and legumes decreased, and forb biomass showed a hump‐shaped relationship with degradation intensity. In addition, the communities transitioned from a clustered to a more random phylogenetic pattern. Soil conditions changed from acidic to alkaline and from fertile to harsh (p <.05). High niche overlap indicates a high biotic filtering at lightly degraded land where abiotic filtering is less stressful. However, when degradation is intense, abiotic filtering is apparent, as indicated by low levels of niche overlap. Overall, we suggest that distantly related, arid tolerant and hardy plants, and soil reclamation should be considered in degraded alpine lands restoration. [ABSTRACT FROM AUTHOR]

The Xianshuihe Fault Belt (XSF), along which the syntectonic Zheduoshan batholith was emplaced, has great significance for the reconstruction of the tectonic framework in the eastern margin of the Tibetan Plateau. In this contribution, formation process and evolution of the XSF are discussed based on the structural deformation in the field and the geochronology of Zheduoshan batholith. The results show that the XSF current arc‐shaped protrusion to the north‐east probably was formed by a fracture of the clockwise rotation compression that extended northward to the periphery with the eastern Himalayan tectonic syntaxis as the centre. It is a complex fault belt formed by the superposition of multi‐stage structures. In the early‐stage formation and evolution of the XSF, the Oligocene‐Miocene migmatite zone and Miocene granites of the Zheduoshan batholith were emplaced. Among them, the lower limit of the XSF's initial activity time was not less than 47 Ma that was limited by the Zircon U–Pb geochronology of migmatite zone formed under the compression system. During the emplacement of Miocene granites, the XSF underwent a process from compression to sinistral strike‐slip, and the geochronology indicates that the onset of the XSF sinistral strike slip should not be less than 14 Ma. After syntectic magmatism, the XSF also experienced the shear deformation (from ductile to brittle) with sinistral kinematics. 40Ar‐39Argeochronology results show that the ductile shear deformation mainly occurred around 5.5–3.2 Ma and accompanied a staged and differential uplift from north to south. It extended to the south along the weak crustal zone of Anninghe, Daliangshan, Xiaojiang, and other faults, forming the Xianshuihe–Anninghe–Xiaojiang sinistral strike‐slip fault system on the eastern margin of the Tibetan Plateau, and large‐scale sinistral strike slip began around 5 Ma. Our new insights lay a foundation for understanding and dissecting the formation and evolution of the Tibetan Plateau eastern margin. [ABSTRACT FROM AUTHOR]

Numerical simulations often overpredict precipitation over the Tibetan Plateau (TP). To examine the factors causing precipitation overprediction, different parameterizations of liquid‐phase microphysical processes (accretion, autoconversion, and entrainment mixing) are implemented into the Morrison microphysics scheme to simulate a TP precipitation event in summer with the Weather Research and Forecasting (WRF) model. The general spatial distribution and temporal trend of precipitation are captured by all simulations, but the precipitation rate is overpredicted. The results from sensitivity experiments suggest that compared to other examined liquid‐phase processes, the accretion process is more important in precipitation simulation over the TP region. Further investigation with the Heidke skill scores reveals that accretion parameterization that takes into account the raindrop size produces the most accurate results in terms of the total surface precipitation. This parameterization suppresses spurious accretion and does not produce liquid‐phase precipitation until cloud droplets are big enough. It is also confirmed that increasing the model resolution can reduce precipitation overprediction. Results from the case study are confirmed by the use of a 1‐month simulation. Key Points: The accretion process plays more important roles than other examined liquid‐phase processesConsidering raindrop size in accretion process suppresses liquid‐phase rain and mitigates the overprediction of precipitation over the TPIncreasing the model resolution can reduce precipitation overprediction [ABSTRACT FROM AUTHOR]

Observations and simulations have shown that the Tibetan Plateau (TP) plays an important role in the climate and weather of East Asia. Uncertainties in reanalysis data sets have been documented by comparing them with independent rawinsonde data, but the impacts of incorporating this data into a reanalysis data set on the dynamical and thermodynamical features over the TP have not been assessed. Observations from the recent Third Tibetan Plateau Atmospheric Scientific Experiment (TIPEX‐III) can be used to evaluate the Eastern TP ERA‐Interim reanalysis data set (ERA). In this study, the Barnes objective analysis scheme is used to incorporate the rawinsonde data into the ERA to acquire the gridded data (OBJ) for examining heat and moisture budgets. It is shown that the OBJ budget‐estimated rainfall intensity is better correlated with the observations than the ERA budget‐estimated rainfall intensity. The ERA overestimates weak rainfall but underestimates heavy rainfall. The incorporation of special rawinsonde into the OBJ impacts the dynamical and thermodynamical characteristics both spatially and temporally. The downward motion and cooling are enhanced over the rainless regions/periods, while the upward motion and heating are enhanced over the rainy regions/periods. The rawinsonde effect is stronger with the increasing rainfall intensity. The differences of spatial distributions and temporal variations in heating between the OBJ and ERA are primarily determined by the vertical advection terms in heat and moisture budgets. The OBJ‐derived large‐scale forcing is essential for cloud‐resolving model simulations of TP cloud systems. The above conclusions can also be applied to the ERA5. Key Points: The inclusion of the rawinsonde data can significantly improve the ERA‐Interim quality over the Tibetan PlateauThe impacts of rawinsonde data on the Tibetan Plateau's dynamical and thermodynamical features are related to the rainfall intensityThe rawinsonde's impacts are primarily determined by the vertical advection terms in heat and moisture budgets [ABSTRACT FROM AUTHOR]

The Dadu River in the eastern Tibetan Plateau has the potential to record transient variations of tectonic uplift since the Late Cenozoic. In this study, we extracted bedrock channels of the Dadu River drainage basin from the 30 m ASTER digital elevation model. The longitudinal river profiles were then analyzed, and three generations of knickpoints were recognized via the slope area method. By solving the analytical solution of the linear transient stream power incision model, we determined a Late Cenozoic history of regional tectonic uplift. The results reveal slow pre–middle Miocene uplift rates (<0.1 mm/a) and then increased gradually to 0.33 ± 0.03 mm/a since 12–15 Ma until present. This increase of uplift rate from bedrock channel inversion is consistent with the regional findings of low‐temperature themochronology, emphasizing the potential and significance to utilize channel profiles to infer the tectonic uplift history. Plain Language Summary: Recently, numerous thermochronology studies have provided constraints on the timing of rapid denudation along the eastern Tibetan Plateau. However, the rates of denudation/uplift determined by thermochronological profiles are often given as an average since a certain time duration. Thus, it is difficult to quantify the history of the tectonic uplift and whether uplift has been uniform or varied through time. We used the linear simulation method and inverted the longitudinal river profiles to decipher the Late Cenozoic uplift history of the eastern Tibetan Plateau. The results reveal that before the middle Miocene, the uplift rate was slow (<0.1 mm/a), and it increased gradually to 0.33 ± 0.03 mm/a since 12–15 Ma until present. Key Points: Linear inversion of the longitudinal river profiles for Tibetan Plateau uplift historyIncrease of the uplift rate since 12-15 Ma, consistent with regional resultsNew evidence of the late Miocene tectonic uplift in eastern Tibet [ABSTRACT FROM AUTHOR]