Acta Scientiarum Naturalium Universitatis Sunyatseni

   

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

LI Minghua1,2, LI Chao1,2,4, CHEN Fangli3, ZHENG Qunfeng1,4, CHEN Qian1,4, ZHANG Chao1,4, ZHAO Chunyang1,4, ZHOU Zuohuan1   

  1. 1. Meteorological Bureau of Shenzhen Municipality, Shenzhen 518040, China;
    2. Shenzhen Key Laboratory of Severe Weather in South China, Shenzhen 518040, China;
    3. Meteorological Bureau of Huizhou, Huizhou 516001, China;
    4. Shenzhen National Climate Observatory, Shenzhen 518040, China
  • Received:2020-02-19 Online:2020-07-22 Published:2020-07-22

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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