North Atlantic forcing of autumn drought in Southwest China
北大西洋对中国西南秋季干旱的影响
中国南西部における北大西洋の秋の干ばつの強制
중국 남서부의 가을 가뭄의 북대서양 강제력
Sequía otoñal forzada en el Atlántico norte en el suroeste de China
Forçage nord-atlantique de la sécheresse automnale dans le sud-ouest de la Chine
Североатлантическое воздействие осенней засухи на юго-западе Китая
Chaoxia Yuan 袁潮霞 ¹, Wei Zhang ¹, Yahan Zhong 钟亚含 ², Xinyu Lu ¹, Jingchan Liu ¹, Md Wahiduzzaman ¹
¹ Key Laboratory of Meteorological Disaster of Ministry of Education, Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Institute for Climate and Application Research (ICAR), Nanjing University of Information Science and Technology, Nanjing, China
中国 南京 南京信息工程大学气候与应用前沿研究院 气象灾害预报预警与评估协同创新中心 气象灾害教育部重点实验室
² Yunnan Institute of Meteorological Sciences, Kunming, China
中国 昆明 云南省气象科学研究所
Atmospheric and Oceanic Science Letters, 16 January 2022
Abstract
Drought often lasts long and is thus closely related to slowly varying external forcing such as sea surface temperature (SST). Here, based on observed precipitation and SST data along with NCEP–DOE reanalysis data, the possible impacts of North Atlantic SST on drought formation in Southwest China are investigated.
Results show that northeast–southwest-orientated dipole SST anomalies in the mid–high latitudes of the North Atlantic are closely related to autumn drought in Southwest China; the linear correlation coefficient between them reaches 0.48 during 1979–2020, significant at the 0.001 level.
The dipole SST anomalies trigger southeastward-propagating Rossby waves and induce barotropic cyclonic circulation anomalies over India and the western Tibetan Plateau. This enhances the upward motion in northern India and the western Tibetan Plateau and causes a compensating downdraft, reduced precipitation, and consequent drought formation in Southwest China.
