气候变化领域集成服务门户(CCPortal): Variability of summertime Tibetan tropospheric temperature and associated precipitation anomalies over the central-eastern Sahel

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DOI	10.1007/s00382-018-4246-8
	Variability of summertime Tibetan tropospheric temperature and associated precipitation anomalies over the central-eastern Sahel
	Nan S.; Zhao P.; Chen J.
发表日期	2019
ISSN	0930-7575
起始页码	1819
结束页码	1835
卷号	52 期号:2020-03-04
英文摘要	The relationship between the Tibetan tropospheric thermal condition and West African monsoon precipitation during boreal summer, and the associated physical mechanisms, are investigated. A significant positive correlation exists between the summertime Tibetan tropospheric temperature (TTT) and central-eastern Sahel precipitation. When the TTT increases, higher-than-normal precipitation occurs over the central-eastern Sahel, and vice versa. The increased tropospheric temperature over the western Tibetan Plateau (TP)−Mediterranean Sea region associated with a high TTT forms a tropospheric temperature gradient from the middle latitudes to the subtropics, which is accompanied by an anomalous zonal-vertical circulation from the western TP to the Mediterranean Sea. The tropospheric temperature distribution associated with a high TTT over the western TP−Mediterranean Sea region contributes to a tropospheric temperature gradient from the eastern Mediterranean and West Asia to the western Mediterranean, which is accompanied by an anomalous meridional-vertical circulation cell over the Mediterranean Sea−Africa region. The meridional-vertical circulation cell is accompanied by a deepened African continental low, and enhanced low-level westerly and southwesterly winds from the tropical and eastern Atlantic to inland Africa. These conditions favor an increase in precipitation over the central-eastern Sahel. Thus, the relationship between the summer TTT and precipitation over the central-eastern Sahel is explained by the anomalous zonal-vertical circulation between the western TP and the Mediterranean Sea, and the anomalous meridional-vertical circulation cell over the Mediterranean Sea–Africa region. The zonal and meridional circulations are connected by the vertical motion over the Mediterranean Sea. Sensitivity experiments with an atmospheric model, in which the surface vegetation type is adjusted, demonstrate the impacts of an increase in the summertime TTT on the anomalous zonal-vertical circulation between the western TP and the Mediterranean Sea, the anomalous meridional-vertical circulation cell over the Mediterranean Sea−Africa region, the deepened African continental low, and the enhanced low-level westerly winds from the tropical and eastern Atlantic to inland Africa. Thus, the relationship between the summertime TTT and central-eastern Sahelian precipitation reflects an impact of the TTT on central-eastern Sahelian precipitation. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
英文关键词	Central-eastern Sahel; Mediterranean Sea; Tibetan plateau; Tropospheric thermal condition; West African monsoon precipitation
语种	英语
scopus关键词	atmospheric circulation; climate variation; monsoon; precipitation (climatology); regional climate; summer; temperature gradient; troposphere; westerly; wind; Atlantic Ocean; Atlantic Ocean (East); Atlantic Ocean (Tropical); China; Mediterranean Sea; Qinghai-Xizang Plateau; Sahel [Sub-Saharan Africa]; West Asia
来源期刊	Climate Dynamics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/146530
作者单位	State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing, 100081, China; Institute of Climate Systems, Chinese Academy of Meteorological Sciences, Beijing, 100081, China; Collaborative Innovation Centre on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing, China
推荐引用方式 GB/T 7714	Nan S.,Zhao P.,Chen J.. Variability of summertime Tibetan tropospheric temperature and associated precipitation anomalies over the central-eastern Sahel[J],2019,52(2020-03-04).
APA	Nan S.,Zhao P.,&Chen J..(2019).Variability of summertime Tibetan tropospheric temperature and associated precipitation anomalies over the central-eastern Sahel.Climate Dynamics,52(2020-03-04).
MLA	Nan S.,et al."Variability of summertime Tibetan tropospheric temperature and associated precipitation anomalies over the central-eastern Sahel".Climate Dynamics 52.2020-03-04(2019).