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Article ; Online: Connection between the Tropical Pacific and Indian Ocean and Temperature Anomaly across West Antarctic

Ping Zhang / Anmin Duan

npj Climate and Atmospheric Science, Vol 6, Iss 1, Pp 1-

2023 Volume 9

Abstract: Abstract West Antarctic and the Antarctic Peninsula have experienced dramatic warming in austral spring since the 1970s. Using observations and the Community Atmosphere Model version 4 (CAM4), this study explores the physical mechanism by which the ... ...

Abstract	Abstract West Antarctic and the Antarctic Peninsula have experienced dramatic warming in austral spring since the 1970s. Using observations and the Community Atmosphere Model version 4 (CAM4), this study explores the physical mechanism by which the tropical Pacific and Indian Ocean temperature anomaly mode (PIM) affects the dipolar surface air temperature (SAT) anomalies across the West Antarctic in austral spring. The positive phase of the PIM, characterized by positive sea surface temperature anomalies (SSTAs) in the tropical central-eastern Pacific and western Indian Ocean and negative SSTAs in the Maritime Continent, can generate two branches of stationary Rossby wave trains propagating from the tropical central Pacific and southeastern Indian Ocean to the West Antarctic, with an anticyclonic anomaly appearing over the Amundsen Sea. The northerlies advect warmer air to the Ross–Amundsen Seas, but southerlies advect colder air to the Antarctic Peninsula–Weddell Sea, resulting in the dipole of SAT anomalies over the West Antarctic. In this process, the role of tropical central-eastern Pacific SSTAs dominate, and it is amplified by the SSTAs around the Maritime Continent. The SSTAs in the western Indian Ocean combined with the SSTAs over the Maritime Continent further contribute to the western pole of the SAT. Only simulation that includes a prescribed PIM forcing can exactly reproduce the observations of the dipolar SAT response across the West Antarctic, indicating the need to treat the tropical Pacific and Indian Oceans as a unified whole.
Keywords	Environmental sciences ; GE1-350 ; Meteorology. Climatology ; QC851-999
Subject code	551
Language	English
Publishing date	2023-05-01T00:00:00Z
Publisher	Nature Portfolio
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Evaluation of the surface air temperature over the Tibetan Plateau among different reanalysis datasets

Yuzhuo Peng / Anmin Duan / Chao Zhang / Bin Tang / Xuejie Zhao

Frontiers in Environmental Science, Vol

2023 Volume 11

Abstract: The surface air temperature (SAT) over the Tibetan Plateau (TP) not only affects the physical processes such as local evaporation, snow melting, and glacier ablation, but also has a great impact on the downstream regions and even the global climate ... ...

Abstract	The surface air temperature (SAT) over the Tibetan Plateau (TP) not only affects the physical processes such as local evaporation, snow melting, and glacier ablation, but also has a great impact on the downstream regions and even the global climate change. The development of reanalysis data has gradually overcome the problem of sparse stations over the TP, but there are still some deficiencies. Therefore, the distance between indices of simulation and observation (DISO) method is used to calculate the distance between five reanalysis datasets (ERA5, JRA-55, ERA-Interim, MERRA2, NCEP2) and the CMFD to evaluate the abilities of different reanalysis datasets to capture the SAT over the TP in different seasons. The results indicate that ERA-Interim has a higher ability to reproduce the SAT over the TP in spring and summer, while it is ERA5 in autumn and winter. It should be noted that although the optimal reanalysis has a better performance in capturing the SAT of the TP, there are still a certain degree of deviations in their spatial fields. We further show the spatial deviation fields of SAT over the TP corresponding to the optimal reanalysis data in different seasons, and analyze the possible reasons. The result implies that the SAT deviation field is mainly related to the snow in winter and spring, while the summer SAT deviation field is mainly related to the water vapor, and the autumn is related to both the snow and the water vapor fields. Overall, the quality of reanalysis data needs to be further improved in the future.
Keywords	surface air temperature ; DISO ; reanalysis ; CMFD ; Tibetan Plateau ; Environmental sciences ; GE1-350
Subject code	550
Language	English
Publishing date	2023-03-01T00:00:00Z
Publisher	Frontiers Media S.A.
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: The Prediction of the Tibetan Plateau Thermal Condition with Machine Learning and Shapley Additive Explanation

Yuheng Tang / Anmin Duan / Chunyan Xiao / Yue Xin

Remote Sensing, Vol 14, Iss 4169, p

2022 Volume 4169

Abstract: The thermal condition over the Tibetan Plateau (TP) plays a vital role in the South Asian high (SAH) and the Asian summer monsoon (ASM); however, its prediction skill is still low. Here, two machine learning models are employed to address this problem. ... ...

Abstract	The thermal condition over the Tibetan Plateau (TP) plays a vital role in the South Asian high (SAH) and the Asian summer monsoon (ASM); however, its prediction skill is still low. Here, two machine learning models are employed to address this problem. Expert knowledge and distance correlation are used to select the predictors from observational datasets. Both linear and nonlinear relationships are considered between the predictors and predictands. The predictors are utilized for training the machine learning models. The prediction skills of the machine learning models are higher than those of two state-of-the-art dynamic operational models and can explain 67% of the variance in the observations. Moreover, the SHapley Additive exPlanation method results indicate that the important predictors are mainly from the Southern Hemisphere, Eurasia, and western Pacific, and most show nonlinear relationships with the predictands. Our results can be applied to find potential climate teleconnections and improve the prediction of other climate signals.
Keywords	South Asian high ; LightGBM ; XGBoost ; climate prediction ; Science ; Q
Subject code	670
Language	English
Publishing date	2022-08-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Reduced Risks of Temperature Extremes From 0.5°C less Global Warming in the Earth's Three Poles

Bin Tang / Wenting Hu / Anmin Duan / Kailun Gao / Yuzhuo Peng

Earth's Future, Vol 10, Iss 2, Pp n/a-n/a (2022)

2022

Abstract: Abstract Future projection of temperature extremes in the “Earth's three poles” (the Arctic, Antarctica, and Third Pole‐Tibetan Plateau [TP]) is of importance to risk assessment and policymaking owing to the high sensitivity to climate change in these ... ...

Abstract	Abstract Future projection of temperature extremes in the “Earth's three poles” (the Arctic, Antarctica, and Third Pole‐Tibetan Plateau [TP]) is of importance to risk assessment and policymaking owing to the high sensitivity to climate change in these regions. In this study, future projections of four extreme temperature indices were constructed after the application of a bias correction method in models of Phase 6 of the Coupled Model Intercomparison Project (CMIP6). The reduced intensification of temperature extremes in the Earth's three poles if warming can be limited to 1.5°C instead of 2°C above the pre‐industrial level was examined. Results showed that all the extreme temperature indices show significant increasing trends under both the SSP2–4.5 and SSP5–8.5 scenarios over the Earth's three poles (SSP: Shared Socioeconomic Pathway). For the coldest night (TNn), warmest night (TNx), and warmest day (TXx), the greatest increase by the end of the 21st century under SSP5–8.5 occurs in the Arctic, followed by the TP and finally Antarctica. For the coldest day (TXn), the greatest increase occurs in the Arctic, followed by Antarctica and finally the TP. If global warming can be limited to 1.5°C rather than 2°C, the intensification of TNn, TNx, TXn, and TXx in the Arctic (Antarctica/TP) under SSP5–8.5 is projected to reduce by 66% (21.7%/44.26%), 50.31% (54.79%/60.52%), 71.58% (12.91%/65.81%), and 41.73% (81.3%/57.34%), respectively, and the results are similar for SSP2–4.5. Therefore, keeping a lower warming target is essential for reducing the risk of extreme events in the Earth's three poles.
Keywords	Environmental sciences ; GE1-350 ; Ecology ; QH540-549.5
Subject code	550
Language	English
Publishing date	2022-02-01T00:00:00Z
Publisher	Wiley
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Atmospheric Bridge Connecting the Barents Sea Ice and Snow Depth in the Mid-West Tibetan Plateau

Yuhang Chen / Anmin Duan / Dongliang Li

Frontiers in Earth Science, Vol

2020 Volume 8

Abstract: In contrast to the rapid warming of the climate, there is growing evidence to indicate that no significant trend exists in the snow cover/depth over the western Tibetan Plateau in recent decades. Here, by analyzing multiple sources of observational and ... ...

Abstract	In contrast to the rapid warming of the climate, there is growing evidence to indicate that no significant trend exists in the snow cover/depth over the western Tibetan Plateau in recent decades. Here, by analyzing multiple sources of observational and reanalysis data, we address the possible interannual connection between the mid-west Tibetan Plateau (MWTP) snow depth and Arctic sea ice. Results indicate that a robust and coherent variation exists between the winter Barents Sea ice concentration and the MWTP snow depth; that is, a positive anomaly of the former can enhance the meridional air temperature gradient to the south and hence accelerate the polar-front westerly jet. As a result, an anomalous Rossby wave propagating upward and equatorward generates, resulting in a dipole pattern of the atmospheric circulation anomaly over the polar region and the Eurasian continent. The anticyclonic circulation anomaly, corresponding to the south center of the dipole pattern, weakens the subtropical westerly jet and forms a southeast wind climbing the MWTP, which enhances the zonal advection and meridional convergence of the atmospheric moisture flux over the MWTP, and hence facilitates the MWTP snowfall. The interannual variation of the Barents Sea ice and the MWTP snow depth are therefore closely connected through the atmospheric bridge effect of the westerly jet and Rossby wave.
Keywords	Arctic sea ice ; Barents Sea ; Rossby wave ; Tibetan Plateau ; snow depth ; Science ; Q
Subject code	551
Language	English
Publishing date	2020-07-01T00:00:00Z
Publisher	Frontiers Media S.A.
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Observational constraint on the future projection of temperature in winter over the Tibetan Plateau in CMIP6 models

Yuzhuo Peng / Anmin Duan / Wenting Hu / Bin Tang / Xinyu Li / Xianyi Yang

Environmental Research Letters, Vol 17, Iss 3, p

2022 Volume 034023

Abstract: The Tibetan Plateau (TP) is known as one of the sentinels of global climate change. Substantial winter warming over the TP will likely lead, directly or indirectly, to a series of geological disasters such as snow and glacial avalanches. Hence, for ... ...

Abstract	The Tibetan Plateau (TP) is known as one of the sentinels of global climate change. Substantial winter warming over the TP will likely lead, directly or indirectly, to a series of geological disasters such as snow and glacial avalanches. Hence, for better adaptation to climate change, it is vital to project the future change in winter temperature over the TP. However, the current state-of-the-art climate models involved in the sixth phase of the Coupled Model Intercomparison Project (CMIP6) still produce strong cold biases over most parts of the TP in their historical simulations. On the basis of selecting the optimal models, here we use the statistical downscaling method to constrain the projected winter temperature in CMIP6 models. The results show that the regions with the strongest winter warming over the TP will be near the Himalayas and the densely populated eastern regions. The constrained warming magnitude is much greater than that in the ensemble mean of the original 32 CMIP6 models or six best models over these regions. Therefore, early warning and forecasting services should be strengthened for the future temperature over these regions. Moreover, the long-term spatial warming varies greatly under four different future emission scenarios. Under the most severe scenario, the increase in winter temperature near the Himalayas exceeds 10 °C, which will greatly destabilize glaciers in the region, while the increase is only 4 °C–6 °C under the weakest scenario. Therefore, it is urgent to reduce greenhouse gas emissions to control the future temperature increase at hotspots of climate vulnerability such as the TP.
Keywords	Tibetan Plateau ; winter temperature ; climate projection ; statistical downscaling ; CMIP6 ; Environmental technology. Sanitary engineering ; TD1-1066 ; Environmental sciences ; GE1-350 ; Science ; Q ; Physics ; QC1-999
Subject code	550
Language	English
Publishing date	2022-01-01T00:00:00Z
Publisher	IOP Publishing
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article: Impacts of the global sea surface temperature anomaly on the evolution of circulation and precipitation in East Asia on a quasi-quadrennial cycle

Liu, Senfeng / Anmin Duan

Climate dynamics. 2018 Dec., v. 51, no. 11-12

2018

Abstract: Based on multi-source observational data from 1979 to 2013, we investigate the evolution of the global sea surface temperature anomaly (SSTA) on a quasi-quadrennial cycle and its impact on the seasonal evolution of circulation and precipitation in East ... ...

Abstract	Based on multi-source observational data from 1979 to 2013, we investigate the evolution of the global sea surface temperature anomaly (SSTA) on a quasi-quadrennial cycle and its impact on the seasonal evolution of circulation and precipitation in East Asia. We do this by using principal oscillation pattern analysis and associated correlation pattern analysis, together with numerical experiments from an atmospheric general circulation model. The results indicate that the global SSTA exerts profound impacts on the East Asian climate anomaly, while distinct responses exist between the SSTA developing and decaying stages. From winter to autumn in the developing year, southern China is typically wetter than normal. In the decaying year, however, the precipitation over most parts of East Asia is above normal from winter to spring, and the main rainfall band meandering from the Yangtze River to South Japan is enhanced in summer. During the developing and decaying years, an upper-level anomalous cyclone moves from Northeast Asia to the Tibetan Plateau, and then retreats back. A low-level anomalous cyclone occurs over Northeast Asia in spring, but weakens in summer and then strengthens gradually from autumn to the following summer. An anomalous Philippine Sea anticyclone occurs in winter and spring, but is replaced by an anomalous cyclone in summer before reappearing and persisting from autumn to the decaying year. The abrupt change in circulation patterns in summer of the developing year might be related to the anomalous weakening of the Tibetan Plateau heating. These anomalies can be attributed to the combined effects of the global large-scale heating, regional-scale oceanic forcing, and thermal feedback of the land.
Keywords	General Circulation Models ; autumn ; climate ; heat ; observational studies ; rain ; spring ; summer ; surface water temperature ; winter ; China ; Japan ; Philippine Sea ; Yangtze River
Language	English
Dates of publication	2018-12
Size	p. 4077-4094.
Publishing place	Springer Berlin Heidelberg
Document type	Article
ZDB-ID	1471747-5
ISSN	1432-0894 ; 0930-7575
ISSN (online)	1432-0894
ISSN	0930-7575
DOI	10.1007/s00382-017-3663-4
Database	NAL-Catalogue (AGRICOLA)

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Article ; Online: Atmospheric heat source/sink dataset over the Tibetan Plateau based on satellite and routine meteorological observations

Anmin Duan / Senfeng Liu / Yu Zhao / Kailun Gao / Wenting Hu

Big Earth Data, Vol 2, Iss 2, Pp 179-

2018 Volume 189

Abstract: The Tibetan Plateau (TP), acting as a large elevated land surface and atmospheric heat source during spring and summer, has a substantial impact on regional and global weather and climate. To explore the multi-scale temporal variation in the thermal ... ...

Abstract	The Tibetan Plateau (TP), acting as a large elevated land surface and atmospheric heat source during spring and summer, has a substantial impact on regional and global weather and climate. To explore the multi-scale temporal variation in the thermal forcing effect of the TP, here we calculated the surface sensible heat and latent heat release based on 6-h routine observations at 80 (32) meteorological stations during the period 1979–2016 (1960–2016). Meanwhile, in situ air-column net radiation cooling during the period 1984–2015 was derived from satellite data. This new dataset provides continuous, robust, and the longest observational atmospheric heat source/sink data over the third pole, which will be helpful to better understand the spatial-temporal structure and multi-scale variation in TP diabatic heating and its influence on the earth’s climatic system.
Keywords	Atmospheric heat source/sink ; dataset ; Tibetan Plateau ; sensible heat ; latent heat ; Geography. Anthropology. Recreation ; G ; Geology ; QE1-996.5
Subject code	551
Language	English
Publishing date	2018-04-01T00:00:00Z
Publisher	Taylor & Francis Group
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Sea ice loss of the Barents-Kara Sea enhances the winter warming over the Tibetan Plateau

Anmin Duan / Yuzhuo Peng / Jiping Liu / Yuhang Chen / Guoxiong Wu / David M. Holland / Bian He / Wenting Hu / Yuheng Tang / Xichen Li

npj Climate and Atmospheric Science, Vol 5, Iss 1, Pp 1-

2022 Volume 6

Abstract: Abstract The Tibetan Plateau (TP) is known as one of the most sensitive regions to climate change, and it has experienced accelerated warming in recent decades. However, to what degree the TP warming amplification relates to remote forcing such as sea ... ...

Abstract	Abstract The Tibetan Plateau (TP) is known as one of the most sensitive regions to climate change, and it has experienced accelerated warming in recent decades. However, to what degree the TP warming amplification relates to remote forcing such as sea ice loss in the Arctic sea ice remains unclear. Here, we found that the decline of sea ice concentration over the Barents-Kara Sea (BKS) could account for 18–32% of the winter warming over the TP by comparing observational data and ensemble experiments from an atmospheric general circulation model. The reduced BKS sea ice and resultant upward turbulent heat fluxes can intensify a Rossby wave train propagating equatorward to the TP. As a result, the enhanced southwesterlies towards the TP strengthen the warm advection over most parts of the TP and lead to TP warming. In addition, an atmospheric teleconnection between the Arctic and the TP also exists in the interannual variability. That is, a tripole mode in air temperature, with warm centers in the Arctic and TP but a cold center in the mid-high latitudes of the Eurasian continent in between. Our results imply that the BKS sea ice loss could intensify such a tripole mode and thus enhancing the winter TP warming.
Keywords	Environmental sciences ; GE1-350 ; Meteorology. Climatology ; QC851-999
Subject code	290
Language	English
Publishing date	2022-03-01T00:00:00Z
Publisher	Nature Portfolio
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article: Tibetan Plateau heating as a driver of monsoon rainfall variability in Pakistan

Wang, Ziqian / Song Yang / Anmin Duan / Wei Hua / Kalim Ullah / Senfeng Liu

Climate dynamics. 2019 May, v. 52, no. 9-10

2019

Abstract: Pakistan summer monsoon rainfall consists of a large portion of the local annual total rainfall, and in the recent monsoon seasons, prolonged periods of anomalous rainfall and excessive flooding have appeared in Pakistan. A full understanding of the ... ...

Abstract	Pakistan summer monsoon rainfall consists of a large portion of the local annual total rainfall, and in the recent monsoon seasons, prolonged periods of anomalous rainfall and excessive flooding have appeared in Pakistan. A full understanding of the monsoon rainfall variability is important for the sustainable development of the country. Based on multiple data analyses and the weather research and forecasting model, the potential impact of Tibetan Plateau (TP) heating on the interannual variability of Pakistan monsoon rainfall is investigated. It is observed that a significant negative relationship exists between the thermal forcing over the southeastern TP and Pakistan monsoon rainfall in July–August. Both the data analyses and model sensitivity experiments identify that the TP heating drives a Rossby wave response in the upper atmosphere characterized with an anticyclonic anomaly over the southern TP but a cyclonic anomaly to the north. This dipole pattern of anomalous circulation induces an evident upper-level convergence over Pakistan, corresponding with remarkable vertical sinking motion. Meanwhile, in the lower troposphere, the TP heating causes anomalous westerly wind along the Himalayas over the northern India continent. Such westerly anomaly further induces less water vapor transport into Pakistan from the Bay of Bengal. Therefore, both the dynamic and thermodynamic processes regulated by positive TP heating are not beneficial for the occurrence of monsoon rainfall in Pakistan. This study proposes a new potential mechanism in which TP heating acts as a driver of Pakistan monsoon rainfall variability on interannual time scales.
Keywords	climate ; heat ; monsoon season ; rain ; summer ; sustainable development ; troposphere ; water vapor ; weather research and forecasting model ; wind direction ; Bay of Bengal ; China ; Himalayan region ; India ; Pakistan
Language	English
Dates of publication	2019-05
Size	p. 6121-6130.
Publishing place	Springer Berlin Heidelberg
Document type	Article
ZDB-ID	1471747-5
ISSN	1432-0894 ; 0930-7575
ISSN (online)	1432-0894
ISSN	0930-7575
DOI	10.1007/s00382-018-4507-6
Database	NAL-Catalogue (AGRICOLA)

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