Anomalous Water Vapor Circulation in an Extreme Drought Event of the Mid-Reaches of the Lancang-Mekong River Basin

Gong, Guoqing1; Zhang, Shuyu1; Li, Baoni1; Chen, Yufan1; Chen, Penghan1; Wang, Kai1; Gan, Thian Yew2,3; Chen, Deliang4; Liu, Junguo1,5

2024-08-01

10.1029/2023EF004292

EARTHS FUTURE   影响因子和分区

2328-4277

["The middle reaches of the Lancang-Mekong River Basin (M-LMRB) experienced a record-breaking drought event in 2019, resulting in significant economic losses of approximately 650 million dollars and affecting a population of 17 million. However, the anomalous circulation and transportation processes of water vapor, which may have played a crucial role in inducing the extreme drought, have not been fully studied. In this study, we analyze the water vapor circulation during the 2019 drought event using the land-atmosphere water balance and a backward trajectory model for moisture tracking. Our results indicate that the precipitation in the M-LMRB from May to October 2019 was only 71.9% of the long-term climatological mean (1959-2021). The low precipitation during this drought event can be attributed to less-than-normal external water vapor supply. Specifically, the backward trajectory model reveals a decrease in the amount of water vapor transported from the Indian Ocean, the Bay of Bengal, and the Pacific Ocean, which are the main moisture sources for precipitation in the region. Comparing the atmospheric circulation patterns in 2019 with the climatology, we identify anomalous anticyclone conditions in the Bay of Bengal, anomalous westerlies in the Northeast Indian Ocean, and an anomalous cyclone in the Western Pacific Ocean, collectively facilitating a stronger export of water vapor from the region. Therefore, the dynamic processes played a more significant role than thermodynamic processes in contributing to the 2019 extreme drought event.","In 2019, a record-breaking drought hit the M-LMRB, leading to significant economic losses and affecting a large population. This study explores the water vapor circulation during this drought using land-atmosphere water balance and a backward trajectory model. Findings show that precipitation from May to October 2019 was only seventy percent of the average from 1959 to 2021. The drought's severity was mainly due to a lack of water vapor from key sources: the Indian Ocean, the Bay of Bengal, and the Pacific Ocean. Anomalous weather patterns-an anticyclone in the Bay of Bengal, unusual westerlies in the Northeast Indian Ocean, and a cyclone in the Western Pacific-led to a significant reduction in water vapor reaching the region. This indicates that dynamic atmospheric processes played a larger role in causing the extreme drought than thermodynamic ones. These insights help improve understanding and prediction of droughts in Southeast Asia, particularly under changing climate conditions.","Reduced external water vapor transport primarily leads to negative precipitation anomalies There has been a reduction in water vapor originating from the Indian Ocean, Bay of Bengal, and Pacific Ocean The reduction in water vapor transport is primarily influenced by dynamic factors rather than thermodynamic ones"]

climate extreme drought Lancang Mekong River basin water vapor transport atmospheric circulation

SCI

英语

第一 ; 通讯

National Natural Science Foundation of China[42361144001] ; Guangdong Basic and Applied Basic Research Foundation[2022A1515011070]

Environmental Sciences & Ecology ; Geology ; Meteorology & Atmospheric Sciences

Environmental Sciences ; Geosciences, Multidisciplinary ; Meteorology & Atmospheric Sciences

WOS:001282307600001

AMER GEOPHYSICAL UNION

Web of Science

1.Southern Univ Sci & Technol, Sch Environm Sci & Engn, Shenzhen, Peoples R China
2.Univ Alberta, Dept Civil & Environm Engn, Edmonton, AB, Canada
3.Univ Colorado Boulder, Dept Environm Studies, Boulder, CO USA
4.Univ Gothenburg, Dept Earth Sci, Gothenburg, Sweden
5.North China Univ Water Resources & Elect Power, Henan Prov Key Lab Hydrosphere & Watershed Water S, Zhengzhou, Peoples R China

Gong, Guoqing,Zhang, Shuyu,Li, Baoni,et al. Anomalous Water Vapor Circulation in an Extreme Drought Event of the Mid-Reaches of the Lancang-Mekong River Basin[J]. EARTHS FUTURE,2024,12(8).

Gong, Guoqing.,Zhang, Shuyu.,Li, Baoni.,Chen, Yufan.,Chen, Penghan.,...&Liu, Junguo.(2024).Anomalous Water Vapor Circulation in an Extreme Drought Event of the Mid-Reaches of the Lancang-Mekong River Basin.EARTHS FUTURE,12(8).

Gong, Guoqing,et al."Anomalous Water Vapor Circulation in an Extreme Drought Event of the Mid-Reaches of the Lancang-Mekong River Basin".EARTHS FUTURE 12.8(2024).