The Spatio-temporal Distribution of Precipitation During Warm Season in Guizhou and Its Relationship with Atmospheric Circulation Anomalies
To strengthen the understanding of the climatic patterns and enhance the prediction ability of precipitation in Guizhou during the warm season(PGWS),based the precipitation observation data,NCEP/NCAR reanalysis data,and HadISST sea surface temperature data,we analyze the spatial and temporal distribution characteristics of PGWS and its relationship with abnormal circulation by various climate statistical methods.The results show that the distribution of PGWS and its percentage of the annual precipitation generally present the pattern of more in the south and less in the north,more in the west and less in the east.In western Guizhou,difference between the dry and wet seasons is more significant and precipitation has an even stronger concentration.There are significant interannual(inter-decadal)variations and quasi-20 years and quasi-7 years oscillation periods of PGWS.The distribution of PGWS is significantly correlated to the SST in the Indian Ocean and Atlantic Ocean in the previous period,and is also associated with the position indexes of subtropical high ridge line and East Asian trough during the same period.When there is excessive PGWS,there is a trough extending from the polar vortex in the Northern Hemisphere towards the Ural Mountains and northern Canada,and the circulation pattern of high west and low east in Northeast Asia is conducive to the strengthening of meridional circulation,guiding the cold air southward to affect southern China.This is accompanied by the abnormal positive circulation ascending branch over the northern side of Guizhou,and the two jointly affect the convergence and uplift of water vapor from the Bay of Bengal and the South China Sea within Guizhou,providing favorable conditions for the formation of precipitation.The distribution of PGWS is also closely related to the SSTA in the North Pacific,the west coast of North America,the western Pacific,the North Atlantic,and the equatorial Atlantic during the previous autumn and winter.Overall,this study reveals the spatial and temporal distribution characteristics of PGWS and its significant relationship with abnormal circulation and previous SST,and could serve as a scientific basis for improving the prediction ability of precipitation in Guizhou in warm season.
Guizhou Provinceprecipitation in warm seasonspatial and temporal distributioncirculation anomaly
NETL
NSTL
万方数据
