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Quantifying the climatic effect on residential electricity consumption (REC) can provide valuable insights for improving climate–energy damage functions. Our study quantifies the effect of climate on the REC in Tibet using machine learning algorithm models and model-agnostic interpretation tools of feature importance scores and partial dependence plots. Results show that the climate contributes about 16.46% to total Tibet REC while socioeconomic factors contribute about 83.55%. Precipitation (particularly snowfall) boosts electricity consumption during the cold season. The effect of the climate is stronger in urban Tibet (~25.06%) than rural Tibet (~14.79%), particularly in September when electricity-aided heating is considered optional, as higher incomes amplified the REC response to the climate. With urbanization and income growth, the climate is expected to contribute more to Tibet REC. Hence, precipitation should be incorporated in climate–REC functions for the social cost of carbon (SCC) estimation, particularly for regions vulnerable to snowfall and blizzards. Herein, we developed a model-agnostic method that can quantify the total effect of the climate while differentiating between contributions from temperature and precipitation, which can be used to facilitate interdisciplinary and cross-section analysis in earth system science. Moreover, this data-driven model can be adapted to warn against extreme weather induced power outages. [ABSTRACT FROM AUTHOR]

Glacier changes on the Tibetan Plateau (TP) have been spatially heterogeneous in recent decades. The understanding of glacier mass changes in western Tibet, a transitional area between the monsoon-dominated region and the westerlies-dominated region, is still incomplete. For this study, we used an energy–mass balance model to reconstruct annual mass balances from October 1967 to September 2019 to explore the effects of local climate and large-scale atmospheric circulation on glacier mass changes in western Tibet. The results showed that Xiao Anglong Glacier is close to a balanced condition, with an average value of −53 ± 185 mm water equivalent (w.e.) yr−1 for 1968–2019. The interannual mass balance variability during 1968–2019 was primary driven by ablation-season precipitation, which determined changes in the snow accumulation and strongly influenced melt processes. The interannual mass balance variability during 1968–2019 was less affected by ablation-season air temperature, which only weakly affected snowfall and melt energy. Further analysis suggests that the southward (or northward) shift of the westerlies caused low (or high) ablation-season precipitation, and therefore low (or high) annual mass balance for glaciers in western Tibet. In addition, the average mass balance for Xiao Anglong Glacier was 83 ± 185, −210 ± 185, and −10 ± 185 mm w.e. yr−1 for 1968–90, 1991–2012, and 2013–19, respectively. These mass changes were associated with the variations in precipitation and air temperature during the ablation season on interdecadal time scales. [ABSTRACT FROM AUTHOR]

In north-western Tibet (34.0° N, 82.2° E) near lake Aru Co, the entire ablation areas of two glaciers (Aru-1 and Aru-2) suddenly collapsed on 17 July and 21 September 2016. The masses transformed into ice avalanches with volumes of 68 and 83×106 m³ and ran out up to 7 km in horizontal distance, killing nine people. The only similar event currently documented is the 130×106 m³ Kolka Glacier rock and ice avalanche of 2002 (Caucasus Mountains). Using climatic reanalysis, remote sensing, and three-dimensional thermo-mechanical modelling, we reconstructed the Aru glaciers' thermal regimes, thicknesses, velocities, basal shear stresses, and ice damage prior to the collapse in detail. Thereby, we highlight the potential of using emergence velocities to constrain basal friction in mountain glacier models. We show that the frictional change leading to the Aru collapses occurred in the temperate areas of the polythermal glaciers and is not related to a rapid thawing of coldbased ice. The two glaciers experienced a similar stress transfer from predominant basal drag towards predominant lateral shearing in the detachment areas and during the 5-6 years before the collapses. A high-friction patch is found under the Aru-2 glacier tongue, but not under the Aru-1 glacier. This difference led to disparate behaviour of both glaciers, making the development of the instability more visible for the Aru-1 glacier through enhanced crevassing and terminus advance over a longer period. In comparison, these signs were observable only over a few days to weeks (crevasses) or were absent (advance) for the Aru-2 glacier. Field investigations reveal that those two glaciers were underlain by soft, highly erodible, and fine-grained sedimentary lithologies. We propose that the specific bedrock lithology played a key role in the two Tibet and the Caucasus Mountains giant glacier collapses documented to date by producing low bed roughness and large amounts of till, rich in clay and silt with a low friction angle. The twin 2016 Aru collapses would thus have been driven by a failing basal substrate linked to increasing pore water pressure in the subglacial drainage system in response to increases in surface melting and rain during the 5-6 years preceding the collapse dates. [ABSTRACT FROM AUTHOR]

Containing elevated topography, the Tibetan Plateau (TP) has significant thermodynamic effects for regional environment and climate change, where understanding energy and water exchange processes (EWEP) is an important prerequisite. However, estimation of the exact spatiotemporal variability of the land-atmosphere energy and water exchange over heterogeneous landscape of the TP remains a big challenge for scientific community. Focused on the above scientific question, a series of atmospheric scientific experiments and research programs have been conducted since the 1960s, quantitatively evaluating both the spatial distribution and the multi-timescale variation of EWEP via observation, remote sensing, and numerical simulation. Based on the three main approaches, the major advances on EWEP over the past 25 years are systematically summarized in this work. Observations reveal distinct characteristics of the energy balance components and micrometeorological parameters. The roughness length for momentum is generally one order of magnitude higher than that for heat, and a distinct diurnal cycle of the excess resistance for heat transfer (kB −1) is captured. These progresses via observations further contributed to the improvement of remote sensing parameterization and numerical simulation of EWEP, e.g., the daily sensible heat flux can be overestimated by approximately 50% using a fixed kB −1, while this overestimation can be mitigated with the observation-captured diurnal variation in kB −1 taken into consideration. Moreover, multisource (multispectral, thermal, and microwave) satellite data have been successfully used to retrieve key land–atmosphere properties, which offers a feasible way to monitor EWEP at different spatiotemporal scales: A decreasing trend of sensible heat flux and an increasing trend of latent heat flux over the TP from 2001 to 2012 were reported. Hourly data of land surface heat fluxes over the entire TP were first obtained, with root mean square errors of 76.6 W m−2 (net radiation flux), 60.3 W m−2 (sensible heat flux), 71.0 W m−2 (latent heat flux) and 37.5 W m−2 (soil heat flux), superior to the previous flux products. The total annual evaporation is approximately 51.7 ± 2.1 km3 year−1 for high-elevation lakes with ice sublimation component accounting for around 10–25%. In addition, different numerical models have been evaluated and improved to study EWEP over heterogeneous land surfaces. The simulation accuracy of land surface temperature and surface energy balance in arid and semiarid areas was improved via an improved heat roughness parameterization scheme in Noah. The sensible heat flux was also effectively improved in the CoLM model by adopting an independent method to determine aerodynamic roughness length. All these results advanced the understanding of different aspects of EWEP over the TP by using in situ measurements, multisource satellite data and numerical modeling. Future studies are recommended to focus on the optimization of the current three-dimensional comprehensive observation system, the development of applicable parameterization schemes and the investigation of EWEP on weather and climate changes over the TP and surrounding regions. [ABSTRACT FROM AUTHOR]

Tibetan forests are located in the southeastern Tibetan Plateau, where the climate is dominated by the Indian monsoon. Due to the affinity to pollution sources and high organic carbon stocks, the fate of persistent organic pollutants in the Tibetan forests should be given more attention. In this study, seven soil profiles were investigated to obtain the vertical distribution of the organochlorine pesticides and polychlorinated biphenyls (PCBs) in the Tibetan forest soil. The results indicate that the DDTs are highly stable in the soil, with limited volatilization and leaching, while the more volatile PCBs were found in the deeper mineral layer, which means that they can translocate through the organic layer and move farther downward into the deep soil. The air-to-ground fluxes (estimated by the age of the organic layer) of the DDTs are one magnitude higher than those reported in a study on the Alps, suggesting the higher accumulation of DDTs by the Tibetan forest. [ABSTRACT FROM AUTHOR]

The resolution and accuracy of digital elevation models (DEMs) can affect the hydraulic simulation results for predicting the effects of glacial lake outburst floods (GLOFs). However, for the Tibetan Plateau, high-quality DEM data are often not available, leaving researchers with near-global, freely available DEMs, such as the Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model (ASTER GDEM) and the Shuttle Radar Topography Mission data (SRTM) for hydraulic modelling. This study explores the suitability of these two freely available DEMs for hydraulic modelling of GLOFs. Our study focused on the flood plain of a potentially dangerous glacial lake in southeastern Tibet, to evaluate the elevation accuracy of ASTER GDEM and SRTM, and their suitability for hydraulic modelling of GLOFs. The elevation accuracies of ASTER GDEM and SRTM were first validated against field global position system (GPS) survey points, and then evaluated with reference to the relatively high precision of 1:50 000 scale DEM (DEM5) constructed from aerial photography. Moreover, the DEM5, ASTER GDEM and SRTM were used as basic topographic data to simulate peak discharge propagation, as well as flood inundation extent and depth in the Hydrologic Engineering Center's River Analysis System one-dimensional hydraulic model. Results of the three DEM predictions were compared to evaluate the suitability of ASTER GDEM and SRTM for GLOF hydraulic modelling. Comparisons of ASTER GDEM and SRTM each with DEM5 in the flood plain area show root-mean-square errors between the former two as ± 15·4 m and between the latter two as ± 13·5 m. Although SRTM overestimates and ASTER GDEM underestimates valley floor elevations, both DEMs can be used to extract the elevations of required geometric data, i.e. stream centre lines, bank lines and cross sections, for flood modelling. However, small errors still exist in the cross sections that may influence the propagation of peak discharge. The flood inundation extent and mean water depths derived from ASTER GDEM predictions are only 2·2% larger and 2·3-m deeper than that of the DEM5 predictions, whereas the SRTM yields a flood zone extent 6·8% larger than the DEM5 prediction and a mean water depth 2·4-m shallower than the DEM5 prediction. The modelling shows that, in the absence of high-precision DEM data, ASTER GDEM or SRTM DEM can be relied on for simulating extreme GLOFs in southeast Tibet. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Based on the study of oxygen isotope and microparticle in the Guliya ice core, atmospheric dust and environmental changes in the northwest Tibetan Plateau since the last interglacial were revealed. The microparticle record indicates that low dust load on the Plateau in the interglacial. Particle concentration increased rapidly when the climate turned into the last glacial and reached the maximum during the MIS 4. In the Last Glacial Maximum, however, the enhancement of microparticle concentration was slight, differing to those in the Antarctic and Greenland. On the orbital timescale, both the temperature on the Tibetan Plateau and summer solar insolation in the Northern Hemisphere had their impact on the microparticle record, but the difference in phase and amplitude also existed. Though having the same dust source, microparticle records in the ice cores on the Tibetan Plateau and the Greenland seem to have different significance. [ABSTRACT FROM AUTHOR]

In the original publication of the article, Fig. 1 caption has been published incorrectly. In the original publication of the article, “OPS” in the note of Table 5 is changed to “QPS”. In the original publication of the article, “Fig. 1” in Line 15 of the second paragraph on Page 4 is changed to “Fig. S1”. In the original publication of the article, “Table S3” in Line 42 of the third paragraph on Page 6 is changed to “Table 3”. In the original publication of the article, “Table 2” in Line 10 of the second paragraph on Page 14 is changed to “Table 4”. [ABSTRACT FROM AUTHOR]

Understanding the spatiotemporal variability of glacier mass balance in the Third Pole (TP) is important in the predictability of regional water supplies and glacier-related natural hazards. However, it is unclear how interannual mass balance variations in glaciers located within different climatic regions of the TP relate to each other. This study studied ablation season (June-September) mass balance variations between glaciers situated in western Tibet, which lies on the transition between monsoon-dominated and westerlies-dominated regions, and the western Tien Shan, which is a region dominated by westerlies. We investigated how these glacier mass balance variations correlated with major atmospheric circulation patterns from 1970 to 2019. At interannual timescales, we showed that ablation season mass balance variations were related to ablation season air temperature and ablation season precipitation in the western Tien Shan, whereas variations in western Tibet were mainly controlled by ablation season precipitation. Further analysis identified a seesaw-style phenomenon in ablation season mass balance variations between the western Tien Shan and western Tibet. These spatial variations resulted from opposing responses of mass balance to shifts in the subtropical westerly jet position during the ablation season. When the subtropical westerly jet moves southward, the western Tien Shan receives a larger amount of precipitation and colder air temperature, which contributes to less negative ablation season mass balance. Concurrently, western Tibet receives less ablation season precipitation, which reduces ablation season mass balance. When the subtropical westerly jet moves northward, these responses are reversed. Changes in the subtropical westerly jet position are influenced by atmospheric circulation in Europe through the European–Asian teleconnection, and by sea surface temperature in the northern Arabian Sea through the Central-Asia–tropical-Indian-Ocean teleconnection. This indicates that interactions between the South Asian monsoon and the westerlies cause opposite ablation season mass balance variations between glaciers in western Tibet and the western Tien Shan at interannual timescales. • A seesaw phenomenon in ablation season mass balance variations was observed between the western Tien Shan and western Tibet. • This phenonmenon was caused by opposing responses of those mass balances to changes in the subtropical westerly jet position. • Changes in the subtropical westerly jet position can be influenced by the European–Asian teleconnection and the Indian Ocean. [ABSTRACT FROM AUTHOR]

Abstract: A drill core (1.8m; 34 samples) was taken out of a swamp near Nam Co (Tibet, China) for palynological analysis. C14-Dating of the cores sediment at 3 different layers led to an numerical core age of about 8000BP and the palynomorph content of prepared samples enabled reconstruction of the vegetation and climatic history of Nam Co Area. Pollen of Alpine Steppe elements together with Cyperaceae dominates the palynoflora reflecting the existing vegetation units around the lake throughout the investigated time span. Due to availability of water/precipitation, the different vegetation units extended or had to retreat, and hence the amount of their pollen increased or decreased. The presence of arboreal plants, verified by charcoal particles, suggest the existence of woodlands in the lake''s surrounding area until possibly human made fires changed the environment over time. Holocene climate history around Nam Co shows several phases of a strengthening/weakening or even an interruption of monsoonal activity. Changing conditions between dry and humid evolved from 8017BP until 4800BP. A mostly humid and relative stable system occurred from 4800 until 700BP whereas the last 700 years are characterized by drier conditions according to fluctuating monsoonal activity. Humid or arid periods have been different in duration and intensity. The interaction of both parts of the monsoonal system, the South Asian Monsoon and the East Asian Monsoon, influenced the climatic conditions around Nam Co. [Copyright &y& Elsevier]