Seasonal thermal regime and climatic trends in lakes of   the Tibetan highlands

Abstract. The hydrology of the lake-rich Tibetan Plateau is important for the global climate, yet little is known about the thermal regime of Tibetan lakes due to scant data. We (i) investigated the characteristic seasonal temperature patterns and recent trends in the thermal and stratification regimes of lakes on the Tibetan Plateau and (ii) tested the performance of the one-dimensional lake parameterization scheme FLake for the Tibetan lake system. For this purpose, we combined 3 years of in situ lake temperature measurements, several decades of satellite observations, and the global reanalysis data. We chose the two largest freshwater Tibetan lakes, Ngoring and Gyaring, as study sites. The lake model FLake faithfully reproduced the specific features of the high-altitude lakes and was subsequently applied to reconstruct the vertically resolved heat transport in both lakes during the last 4 decades. The model suggested that Ngoring and Gyaring were ice-covered for about 6 months and stratified in summer for about 4 months per year with a short spring overturn and a longer autumn overturn. In summer the surface mixed boundary layer extended to 6–8 m of depth and was about 20 % shallower in the more turbid Gyaring. The thermal regime of the transparent Ngoring responded more strongly to atmospheric forcing than Gyaring, where the higher turbidity damped the response. According to the reanalysis data, air temperatures and humidity have increased, whereas solar radiation has decreased, since the 1970s. Surprisingly, the modeled mean lake temperatures did not change, nor did the phenology of the ice cover or stratification. Lake surface temperatures in summer increased only marginally. The reason is that the increase in air temperature was offset by the decrease in radiation, probably due to increasing humidity. This study demonstrates that air temperature trends are not directly coupled to lake temperatures and underscores the importance of shortwave radiation for the thermal regime of high-altitude lakes.

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Seasonal thermal regime and climatic trends in lakes of Tibetan Highlands

10.5194/hess-2016-632 ◽

2016 ◽

Cited By ~ 1

Author(s):

Georgiy Kirillin ◽

Lijuan Wen ◽

Tom Shatwell

Keyword(s):

Tibetan Plateau ◽

High Altitude ◽

Air Temperature ◽

Thermal Regime ◽

Mixed Boundary ◽

Reanalysis Data ◽

Wave Radiation ◽

The Tibetan Plateau ◽

Seasonal Temperature ◽

High Altitude Lakes

Abstract. The hydrology of the lake-rich Tibetan Plateau is important for the global climate yet little is known about the thermal regime of Tibetan lakes due to scant data. We (i) investigated the characteristic seasonal temperature patterns and recent trends in thermal and stratification regime of lakes on the Tibetan Plateau and (ii) tested theperformance of the one-dimensional lake parameterization scheme FLake for the Tibetan lake system. For this purpose we combined three years of in situ lake temperature measurements, several decadesof satellite observations and the global reanalysis data. We chose the two largest freshwater Tibetan lakes – Ngoring and Gyaring – as study sites. The lake model FLake faithfully reproduced the specific features of the high-altitude lakes and was subsequently applied to reconstruct the vertically resolved heat transport in both lakes during the last four decades. The modelsuggested Ngoring and Gyaring were ice-covered forabout 6 months and stratified in summer for about 4 months per year with a short spring overturn and longer autumn overturn. In summer the surface mixed boundary layer extended to 6–8 m depth and was about 20 % shallower in the more turbid Gyaring. The thermal regime of transparent Ngoring responded more strongly to atmospheric forcing than Gyaring, where the higher turbidity dampened the response. According to reanalysis data, air temperatures and humidity increased, whereas solar radiation decreased since the 1970s. Surprisingly, mean lake temperatures did not change, nor did the phenology of ice cover or stratification. Lake surface temperatures in summerincreased only marginally. The reason is that the increase in air temperature was offset by the decrease in radiation, probably due to increasing humidity. This study demonstrates that air temperature trends are not directly coupled to lake temperatures and underscores the importance of short-wave radiation for the thermal regime of high-altitude lakes.

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Air pollution slows down surface warming over the Tibetan Plateau

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-881-2020 ◽

2020 ◽

Vol 20 (2) ◽

pp. 881-899 ◽

Cited By ~ 1

Author(s):

Aolin Jia ◽

Shunlin Liang ◽

Dongdong Wang ◽

Bo Jiang ◽

Xiaotong Zhang

Keyword(s):

Climate Change ◽

Air Pollution ◽

Tibetan Plateau ◽

Air Temperature ◽

Surface Radiation ◽

Shortwave Radiation ◽

Cmip5 Models ◽

The Tibetan Plateau ◽

Anthropogenic Aerosols ◽

Surface Warming

Abstract. The Tibetan Plateau (TP) plays a vital role in regional and global climate change. The TP has been undergoing significant surface warming starting from 1850, with an air temperature increase of 1.39 K and surface solar dimming resulting from decreased incident solar radiation. The causes and impacts of solar dimming on surface warming are unclear. In this study, long-term (from 1850 to 2015) surface downward radiation datasets over the TP are developed by integrating 18 Coupled Model Intercomparison Project phase 5 (CMIP5) models and satellite products. The validation results from two ground measurement networks show that the generated downward surface radiation datasets have a higher accuracy than the mean of multiple CMIP5 datasets and the fused datasets of reanalysis and satellite products. After analyzing the generated radiation data with four air temperature datasets, we found that downward shortwave radiation (DSR) remained stable before 1950 and then declined rapidly at a rate of −0.53 W m−2 per decade, and that the fastest decrease in DSR occurs in the southeastern TP. Evidence from site measurements, satellite observations, reanalysis, and model simulations suggested that the TP solar dimming was primarily driven by increased anthropogenic aerosols. The TP solar dimming is stronger in summer, at the same time that the increasing magnitude of the surface air temperature is the smallest. The cooling effect of solar dimming offsets surface warming on the TP by 0.80±0.28 K (48.6±17.3 %) in summer since 1850. It helps us understand the role of anthropogenic aerosols in climate warming and highlights the need for additional studies to be conducted to quantify the influence of air pollution on regional climate change over the TP.

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Air pollution slows down surface warming over the Tibetan Plateau

10.5194/acp-2019-553 ◽

2019 ◽

Author(s):

Aolin Jia ◽

Shunlin Liang ◽

Dongdong Wang ◽

Bo Jiang ◽

Xiaotong Zhang

Keyword(s):

Climate Change ◽

Air Pollution ◽

Tibetan Plateau ◽

Air Temperature ◽

Surface Radiation ◽

Shortwave Radiation ◽

Cmip5 Models ◽

The Tibetan Plateau ◽

Anthropogenic Aerosols ◽

Surface Warming

Abstract. The Tibetan Plateau (TP) plays a vital role in regional and global climate change. The TP has been undergoing significant surface warming since 1850, with an air temperature increase of 1.39 K and surface solar dimming resulting from decreased incident solar radiation. The causes and impacts of solar dimming on surface warming are unclear. In this study, long-term (from 1850–2015) surface downward radiation datasets over the TP are developed by integrating 18 Coupled Model Intercomparison Project Phase 5 (CMIP5) models and satellite products. The validation results from two ground measurement networks show that the generated downward surface radiation datasets have higher accuracy than the mean of multiple CMIP5 and the fused datasets of reanalysis and satellite products. After analyzing the generated radiation data with four air temperature datasets, we found that downward shortwave radiation (DSR) remained stable before 1950 and then declined rapidly at a rate of −0.53 W m−2 per decade and that the fastest decrease in DSR is in the southeastern TP. Evidence from site measurements, satellite observations, reanalysis, and model simulations suggested that TP solar dimming was primarily driven by increased anthropogenic aerosols. The TP solar dimming is stronger in summer, at the same time that the increasing magnitude of the surface air temperature is the smallest. The cooling effect of solar dimming offsets surface warming on the TP by 0.80 ± 0.28 K (48.6 ± 17.3 %) in summer. It helps us understand the role of anthropogenic aerosols in climate warming, and highlights the need for additional studies to be conducted to quantify the influence of air pollution on regional climate change over the TP.

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Salinity Impact on Bacterial Community Composition in Five High-Altitude Lakes from the Tibetan Plateau, Western China

Geomicrobiology Journal ◽

10.1080/01490451.2012.710709 ◽

2013 ◽

Vol 30 (5) ◽

pp. 462-469 ◽

Cited By ~ 23

Author(s):

Yongqin Liu ◽

Tandong Yao ◽

Nianzhi Jiao ◽

Liping Zhu ◽

Anyi Hu ◽

...

Keyword(s):

Tibetan Plateau ◽

Bacterial Community ◽

High Altitude ◽

Community Composition ◽

Bacterial Community Composition ◽

Western China ◽

The Tibetan Plateau ◽

High Altitude Lakes

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Analysis of the Radiation Fluxes over Complex Surfaces on the Tibetan Plateau

Water ◽

10.3390/w13213084 ◽

2021 ◽

Vol 13 (21) ◽

pp. 3084

Author(s):

Chunxiao Wang ◽

Yaoming Ma ◽

Binbin Wang ◽

Weiqiang Ma ◽

Xuelong Chen ◽

...

Keyword(s):

Tibetan Plateau ◽

Surface Temperature ◽

Air Temperature ◽

Surface Albedo ◽

Longwave Radiation ◽

Heat Fluxes ◽

Shortwave Radiation ◽

The Tibetan Plateau ◽

Downward Shortwave Radiation ◽

Downward Longwave Radiation

Analysis of long-term, ground-based observation data on the Tibetan Plateau help to enhance our understanding of land-atmosphere interactions and their influence on weather and climate in this region. In this paper, the daily, monthly, and annual averages of radiative fluxes, surface albedo, surface temperature, and air temperature were calculated for the period of 2006 to 2019 at six research stations on the Tibetan Plateau. The surface energy balance characteristics of these six stations, which include alpine meadow, alpine desert, and alpine steppe, were then compared. The downward shortwave radiation at stations BJ, QOMS, and NAMORS was found to decrease during the study period, due to increasing cloudiness. Meanwhile, the upward shortwave radiation and surface albedo at all stations were found to have decreased overall. Downward longwave radiation, upward longwave radiation, net radiation, surface temperature, and air temperature showed increasing trends on inter-annual time scales at most stations. Downward shortwave radiation was maximum in spring at BJ, QOMS, NADORS, and NAMORS, due to the influence of the summer monsoon. Upward shortwave radiation peaked in October and November due to the greater snow cover. BJ, QOMS, NADORS, and NAMORS showed strong sensible heat fluxes in the spring while MAWORS showed strong sensible heat fluxes in the summer. The monthly and diurnal variations of surface albedo at each station were “U” shaped. The diurnal variability of downward longwave radiation at each station was small, ranging from 220 to 295 W·m−2.The diurnal variation in surface temperature at each station slightly lagged behind changes in downward shortwave radiation, and the air temperature, in turn, slightly lagged behind the surface temperature.

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