摘要
利用山东省内1960-2003年40个观测站的夏季降水资料和NCEP/NCAP再分析资料,分析了山东夏季降水空间分布、时间尺度的演变特征以及山东夏季降水异常时大气环流、热带对流活动的异常特征,结果表明:山东夏季降水总体呈现由鲁南向鲁北递减的趋热,空间分布具有一致性。涝年的前期冬季极涡向东扩展,东亚大槽和东亚冬季风较常年偏强;旱年前期冬季极涡偏向西半球,东亚大槽和东亚冬季风较常年偏弱。涝年热带印度洋、南海至西太平洋地区对流增强,热带东太平洋地区对流减弱,西太平洋副热带高压位置偏北;旱年则相反。涝年前期冬季由于冬季风较强及低纬度地区冷涌活跃,加强了低纬地区的对流活动,增强了Hadely环流,加强了能量及水汽向中、高纬度地区的输运,从而引起山东降水增多。
By using monthly averaged NCEP/NCAR reanalysis data of the atmospheric circulation and the data of summer precipitation in 40 meteorological stations in Shandong province from 1960 to 2003, spatial and temporal characteristics of summer precipitation were analyzed. The atmospheric circulation characteristics and tropical convection were researched. The results showed the summer precipitation was downtrend from south to north of Shandong, and the spatial distribution was consistent. Before the flood year, wintertime polar vortex expanded eastward, and the East Asia major deep trough and the East Asian winter monsoon were stronger than normal years. And those were contrary to the drought year. The convection was enhancing from tropical Indian Ocean area, South China Sea to West Pacific Ocean area; the convection was weakening in tropical East Pacific Ocean area; the subtropical high pressure of West Pacific Ocean slanted to the north. The drought year and floor year were contrary results. The strength of winter monsoon and the activity of cold surge occurrence in low latitude enhanced convection and Hadely circulation, and they also enhanced energy water transportation. They are some previous signals for forecasting summer precipitation in Shandong.
出处
《气象与环境科学》
2007年第1期76-79,共4页
Meteorological and Environmental Sciences
关键词
夏季降水
预测
前兆信号
Summer precipitation
Forecast
Previous signal
