基于1998-2017年海南岛地区18个台站逐日降水观测数据、TRMM逐日降水数据和ERA5再分析数据集等资料，使用资料统计分析和数值模式模拟等方法，对海南岛地区秋汛期形成原因进行了研究。观测分析表明，海南岛地区的降水随季节的变化与华南及同纬度带的其他地区存在显著差异，降水季节峰期出现在秋季，主要集中于9-10月。秋季，西南夏季风开始向东北冬季风转换，受其影响，海南岛地区上空处于偏东气流带中，秋汛期降水分布明显东多西少，且降水中心位于山前迎风坡一侧，东风气流在钟形地形的阻挡抬升作用下，致使其东部降水增多。此时秋季南海海表温度仍较高，有利于维持和增强海南岛秋季降水。通过WRF v4。3(Weather Research and Forecast Version 4。3)一系列的数值敏感性试验，验证了海南岛地形、海陆热力差异及南海较高的海温对海南岛秋汛期的形成起着决定性作用。
A study on causes of the autumn heavy rainy season formation over Hainan Island
Based on the observed daily precipitation data from 18 meteorological stations in Hainan Island,TRMM daily precipitation data and ERA5 reanalysis datasets from 1998 to 2017,the causes of formation of the Autumn Heavy Rainy Season over Hainan Island(AHRSHI)were investigated by using statistical analysis and numerical model simulations.Observational analysis shows that the seasonal variation of precipitation in Hainan Island is significantly different from that in South China and other areas of the same latitude belt,with the seasonal peak of precipitation occurring in autumn,mainly in September-October.In autumn,the southwest summer monsoon begins to shift to the northeast winter monsoon.Influenced by the northeast monsoon,the air over Hainan Island is in the easterly flow belt,and the precipitation in the AHRSHI is obviously more in the east than in the west.Moreover,the precipitation center is located on the windward side of the mountain front,and the easterly flow under the blocking and lifting effect of the bell-shaped topography let to the increase of precipitation in the east.At this time,the Sea Surface Temperature(SST)of the South China Sea(SCS)in autumn is still in a relatively high state,which is conducive to maintaining and enhancing the AHRSHI.It is verified that the topography of Hainan Island,the sea-land thermal contrast,and the high SST in the SCS play a decisive role in the formation of the AHRSHI by a series of numerical model simulations,using Weather Research and Forecast Version 4.3(WRF v4.3).
Hainan Islandautumn heavy rainy seasoncirculation characteristicsnumerical simulation
万方数据
维普
