东亚低纬地区局地Hadley环流特征及其与大气臭氧的关系

CHARACTERISTICS OF LOCAL HADLEY CIRCULATION AND ITS RELATION TO ATMOSPHERIC OZONE OVER THE LOW-LATITUDE REGIONS IN EAST ASIA

利用1975—2008年NCEP/NCAR的逐月平均风场资料及1975—2001年ECMWF的逐月多层臭氧质量混合比资料,用大气环流三维分解方法研究了东亚低纬度地区之局地Hadley环流的结构及年代际演变特征,分析了该区域局地Hadley环流异常时对应大气臭氧的空间距平分布。研究结果表明:(1)东亚低纬度地区局地Hadley环流既与纬圈平均Hadley环流具有明显的季节变化,但又具有明显区别于纬圈平均Hadley环流的自身结构特征:除冬季存在明显向南、向北输送的两闭合环流圈外,局地Hadley环流在其余季节均以向南输送为主;(2)该局地Hadley环流具有不同于纬圈平均Hadley环流的年代际演变特征,在整个研究时段上以振荡变化为主,并没有表现出象纬圈平均值那样明显的增强趋势;(3)区域赤道上空平流层20～50 hPa大气臭氧的正负距平异常中包含有局地Hadley环流的异常信息:当局地Hadley环流异常强时,区域赤道上空20～50 hPa大气臭氧有一显著负距平异常中心,反之亦然。

Based on NCEP/NCAR monthly mean wind data during the periods of 1975-2008 and ECMWF monthly mean multi-layered ozone mass mixing ratio data during the periods of 1975-2001, and by using the three-dimensional decomposition of atmospheric general circulation method, the structure and interdecadal evolution characteristics of the local Hadley circulation （LHC） over the low-latitude regions in East Asia are studied. And the distribution of the spatial anomaly of atmospheric ozone over the region is analyzed for anomalous LHC. The results showed the following features. （1） Both the LHC and the zonal mean of global Hadley circulation （GHC） have some common features, e.g., both of them have obvious seasonal variation. But some differences also exist between them in structural features. That is, in winter time the LHC has two closed circulation circles transporting to the south and north respectively, while in other seasons the LHC transports mainly to the south. （2） There is evident difference between the LHC and the GHC in the interdecadal evolution. Throughout the study period, the LHC mainly shows an oscillatory variation instead of an obvious increasing trend as the GHC. （3） The positive and negative anomalies in the ozone variation at 20 - 50 hPa over the equator region contain the abnormal signal of the LHC. When the LHC is exceptionally strong, the atmospheric ozone has a remarkable negative anomaly center at 20 - 50 hPa over the equator region, and vice verse.