Acta Scientiarum Naturalium Universitatis Sunyatseni ›› 2020, Vol. 59 ›› Issue (5): 113-125.doi: 10.13471/j.cnki.acta.snus.2020.02.19.2020D006

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On the circulation feature of early rainy season and its precursorsin storm center of eastern Guangdong

LI Minghua12LI Chao124CHEN Fangli3ZHENG Qunfeng14CHEN Qian14ZHANG Chao14ZHAO Chunyang14ZHOU Zuohuan1   

  1. 1. Meteorological Bureau of Shenzhen MunicipalityShenzhen 518040China

    2. Shenzhen Key Laboratory of Severe Weather in South ChinaShenzhen 518040China

    3. Meteorological Bureau of HuizhouHuizhou 516001China 4. Shenzhen National Climate Observatory,Shenzhen 518040,China

  • Received:2020-02-19 Online:2020-09-25 Published:2020-09-25

Abstract: The interannual variation of early rainy season precipitation over the storm center of eastern Guangdong from 1967 to 2018,and the association with the large-scale atmospheric circulation characteristics and the precursory oceanic conditions were analyzed in this present paper. The interannual variation has strengthened since 1990s. The years with rainfall amount above normal have occurred more frequently since 2005. The circulation features were significantly between wet and dry years. The atmospheric conditions of enhanced upper-tropospheric jet,the larger subtropical high area than normal,the deepened East Asian trough,as well as the weakened southerly wind over Jiangnan area were favorable for the convergence over the storm center of eastern Guangdong in wet years. The atmospheric features of northward shift of upper- tropospheric jet,the smaller subtropical high area,strengthened continental high over East Asia,and consistent weakened southerly winds went against the convergence over the storm center of eastern Guangdong in dry years. The less(more)ice concentration in polar area and warm(cold)SST over eastern Pacific Ocean were the most significant precursors responsible for the precipitation anomalies. Further investigation showed the significant relation between ice concentration in polar area and upper- tropospheric jet,East Asian trough. On the other hand,the strong association between SST over eastern Pacific Ocean and subtropical high over western Pacific was also confirmed.

Key words: precipitation in early rainy season, upper- tropospheric jet, subtropical high, ice concentration in polar area, SST over eastern Pacific, rainstorm center of eastern Guangdong

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