Gaoyuan qixiang (Dec 2022)

Relationship between the Subtropical Westerly Jet and Summer Rainfall over Central Asia from 1961 to 2016

  • Guoqiang REN,
  • Yong ZHAO

DOI
https://doi.org/10.7522/j.issn.1000-0534.2021.00082
Journal volume & issue
Vol. 41, no. 6
pp. 1425 – 1434

Abstract

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Based on the reanalysis data provided by the National Center for Environmental Prediction （NCEP）/National Center for Atmospheric Research （NCAR） and the monthly precipitation data provided by the Global Precipitation Climatology Center （GPCC） from 1961 to 2016， the relationships between the subtropical westerly jet and summer rainfall over central Asia were analyzed.The results show that when the subtropical westerly jet shifts south， the anomalous cyclone determines the central Asia， meantime the anomalous anticyclone over the Indian Peninsula and anomalous cyclone over central Asia transport the water vapor from the Arabian Sea into the central Asia， which cause more summer rainfall over central Asia， vice versa.The plateau monsoon over the TQinghai-Xizang Plateau and the surface sea temperature （SST） tropical Indian Ocean are well related to the jet position of subtropical westerly jet over central Asia.When positive anomalies of SST over whole tropical Indian Ocean， corresponding to weakened south Asian summer monsoon， it causes less rainfall and weakened latent heat over the Indian Peninsula.Based on the Gill atmospheric response， there is an anomalous cyclone over northwest flank of Indian Peninsula in upper troposphere， which causes the cooling of temperature in upper troposphere over central Asia； When the strengthened plateau monsoon over the Qinghai-Xizang Plateau， corresponding to more rainfall and strengthened latent heat， it causes an anomalous anticyclone over northwest flank of Qinghai-Xizang Plateau， which results in the cooling of temperature in upper troposphere over central Asia.Under the joint action of the plateau monsoon and SST over the Indian Ocean， the cooling of temperature in upper troposphere forms an anomalous cyclone in upper troposphere over central Asia， it causes more strengthened westerly at middle-low latitudes， corresponding to the jet shifting south， vice versa.

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