摘要
采用海温资料和NCEP/NCAR 49 a再分析的高度场、风场资料,利用EOF、合成分析方法,研究了夏季暖池SSTA的时空演变,结果显示:夏季暖池SSTA具有整体一致性分布和南北区域的反对称分布两种空间分布型。根据这两种分布型划分了夏季暖池海温正、负异常年,分析了相应年份的风场环流特征,结果表明:SSTA为一致性分布时,暖异常年850 hPa暖池区上空有一反气旋偏差环流,副热带地区西风和低纬度地区东风都得到加强,200 hPa南亚上空为一反气旋偏差环流,沃克环流得到加强;冷异常年则相反。当SSTA为南北反对称分布时,北暖南冷年850 hPa暖池区上空为一反气旋偏差环流,15°N附近东风气流和赤道附近西风气流增强,200 hPa反气旋偏差环流中心移到东亚大陆上空,长江中下游地区为上升气流,降水明显增多,华北地区为下沉气流,降水减少;冷异常年则相反。
Based on the 1950-1998 SST and NCEP/NCAR variations of SSTA in the Western Pacific Warm Pool region reanalysis data, the temporal/spatial have been analyzed in this paper by means of the methods of EOF and composite analysis. Results show that there are two main spatial patterns of the WP SSTA ： one is uniform in the whole region, the other is meridionally anti-symmetric. When the spatial pattern of SSTA is uniform in the whole region, in the warm years, an anticyclonic anomaly circulation exists over the warm pool and the westerly/easterly in the subtropical/ tropical region are greatly strengthened at 850 hPa, while an anticyclonic anomaly circulation over the India region at 200 hPa,and the Walker circulation are strengthened,and vice versa. When the spatial pattern is meridionally anti-symmetric, in the noah-warm/south-cold years, an anticyclonic anomaly circulation exists over the warm pool at 850 hPa,the easterly near 15°N and the westerly near the equator are greatly strengthened, while the center of the 200 hPa anticyclonic circulation moves to the East Asia ,and the Hadley circulation is affected evidently, so the summer rainfall may be above normal in the middle and lower reaches of the Yangtze River, and vice versa.
出处
《南京气象学院学报》
CSCD
北大核心
2005年第6期746-754,共9页
Journal of Nanjing Institute of Meteorology
基金
教育部资助优秀青年教师基金项目
关键词
暖池SSTA
海温分布型
大气环流
夏季降水
SSTA in the warm pool
spatial patterns of SSTA
general circulation
summer rainfall
