江淮梅雨异常与东亚地区地表感热通量的关系

Relationships Between Precipitation Anomaly in Meiyu Period in the Yangtze-Huaihe Region and Surface Sensible Heat Flux over East Asia

利用1951-2013年江淮地区30个代表站点逐日降水观测资料和NCEP/NCAR全球地表感热通量和环流场逐月再分析资料,探讨江淮梅雨异常与梅雨期及其前后东亚地区地表感热通量的相关关系及其物理机制。结果表明:梅雨前期,青藏高原、内蒙古高原和印度半岛的地表感热通量与江淮梅雨量存在正相关,当春季青藏高原、内蒙古高原、印度半岛地表感热通量异常偏高时,江淮梅雨偏多;梅雨期,梅雨量与地表感热通量显著负相关区在东海海面,同时青藏高原和河套平原地表感热通量在丰梅年显著偏大,说明海陆热力差异对江淮梅雨有共同调制作用;梅雨后期,河套平原、华北地区地表感热通量在丰梅年显著偏大,表明地表热力特征随大气环流的调整而发生演变。

Based on the daily observational precipitation at 30 representative stations of the Yangtze-Huaihe region and monthly reanalysis data of global surface sensible heat flux and circulation fields from NCEP/NCAR during 1951-2013, the correlation between Meiyu anomaly in the Yangtze-Huaihe region and surface sensible heat flux over East Asia in previous, same and post periods of Meiyu and their physical mechanisms were discussed by using correlation analysis and composite analysis methods. The results show that the precipitation in Meiyu period in the Yangtze-Huaihe region was significantly and positively correlated with surface sensible heat flux over the Tibetan Plateau, Inner Mongolia Plateau and Indian Peninsula in previous period of Meiyu. When the surface sensible heat flux over the Tibetan Plateau, Inner Mongolia Plateau and Indian Peninsula was abnormally higher in spring, the precipitation in Meiyu period in the Yangtze-Huaihe region was more. During the Meiyu period, the precipitation in the Yangtze-Huaihe region was significantly and negatively correlated with surface sensible heat flux over the East Sea of China, and the surface sensible heat flux over the Tibetan Plateau and Hetao Plain was significantly stronger in more Meiyu years, which indicated the modulation of thermal difference over land and sea on precipitation in Meiyu period was common. During the post period of Meiyu, the surface sensible heat flux over Hetao Plain and North China was significantly stronger in more Meiyu years, which indicated the surface thermal characteristics changed with the adjustment of atmospheric circulation.