Page 174 - 《高原气象》2021年第5期

5 期 王大勇等：2019年5-8月山西省中南部严重干旱气候特征及其成因分析 1135

Climatic Characteristics and Causes of Severe Drought in the Central

and Southern Shanxi Province from May to August in 2019

WANG Dayong，CHEN Ying，ZHANG Dongfeng，YAN Jiahai，ZHANG Guohong
（Shanxi Climate Center，Taiyuan 030006，Shanxi，China）

Abstract：From May to August in 2019，a severe drought climate events occurred in the central and southern
Shanxi Province（an important agricultural production center in the region），which caused great economic loss‐
es. This severe drought event on a large scale in Shanxi Province can be attributed to the lack of precipitation for
a long time. Based on the monthly precipitation data of 108 stations in Shanxi Province，NCEP / NCAR reanaly‐
sis data and COBE-SST sea surface temperature data provided by Japan Meteorological Agency，the characteris‐
tics of atmospheric circulation anomaly and sea surface temperature anomaly during drought period and their in‐
fluence on drought are analyzed. The results show that：（1）During the drought period，the 500 hPa height field
over the middle and high latitudes of Asia was dominated by the latitudinal circulation. And Shanxi Province was
mainly affected by the strong high pressure ridge near Lake Baikal. Overall，Shanxi Province is controlled by
the positive anomaly of the height field. Compared with normal years，the Western Pacific subtropical high
showed southwestward extension and southward expansion in the study period，which is unfavorable for the wa‐
ter vapor transportation to northern China；The South Asia high is located more eastward than 10 degree longi‐
tudes with stronger intensity，which is not conducive to the precipitation over Shanxi. （2）There is a weak north‐
erly wind anomaly at low altitude 850 hPa wind field during the drought period over Shanxi with multiple branch‐
es of water vapor from the equator and the western Pacific Ocean converging to reach the south of Yangtze River
in China. The strong water vapor transport flux paths do not pass through Shanxi and it is located by the south，
resulting in an overall lack of abundant water vapor conditions in Shanxi. （3）During the drought period，the
SST in the equatorial Middle East Pacific shows a neutral warming state. And the SST in Indian Ocean shows a
uniform warm mode. For the North Atlantic triode，the SST shows a positive phase，which is conducive to the
less precipitation in Shanxi. In addition，the characteristics of anomal in SST in the winter of 2019 are also favor‐
able for the less precipitation from May to August in 2019 in Shanxi Province. In general，the characteristics of
anomalies in atmospheric synoptic circulation and sea surface temperature during the drought period are consis‐
tent with the typical conditions of anomalies in the years with weak precipitation in Shanxi Province.
Key words：Drought；precipitation；atmospheric circulation；sea surface temperature