使用1979--2001年ERA-40月平均经向风计算了季风区(60~140°E)及Nifio区(160°E°120ow)的质量流函数,并分析了两区Hadley环流的气候特征和强度变化,研究了Hadley环流强度与太平洋海表温度的联系。结果表明:(1)季风区气候态Hadley环流强于Nifio区,环流位置偏北,夏半年尤为明显,造成差异的主要原因是海陆分布不均和赤道东太平洋冷水区的存在;(2)局域Hadley环流强度有明显的年际变化,23年来两区强度大致呈反相变化;(3)局域Hadley环流强度与太平洋海表温度关系密切,1月季风区(Nifio区)环流强度与赤道中、东太平洋的Nifio综合区海表温度负(正)相关,而与围绕着Nifio综合区的C型区域海表温度正(负)相关,7月与1月的相关型基本一致,负相关比1月弱,特别是季风区;(4)ENSO事件对两区Hadley环流强度有不同影响,E1Nifio事件时季风区Hadley环流减弱、Nifio区Hadley环流增强;LaNifia时刚好相反,且Nifio区的异常更明显。
The mass stream function in the monsoon zone (60-140°E) and Nifio zone (160 °E-120 °W) is respectively calculated based on ERA-40 1979--2001 monthly mean meridional wind, and the climatological characteristic, intensity change of the Hadley cell in these two regions and their relationship with the Pacific sea surface temperature(SST) are analyzed. The results are as follows. (1) The intensity of(climatological) Hadley cell in the monsoon zone is stronger than that in the Nifio zone, and the location of the cell in the monsoon zone is further north than that in Nifio zone, especially in the summer half-year, which mainly attributes to the land-sea contrast and a cold water zone in tropical eastern Pacific. (2) The time series of the intensity index of the Hadley cells in the monsoon zone and Nifio zone are out of phase approximately with obvious interannual variation. (3) The intensity variation of local Hadley cells is inherently connected with the Pacific SST. Significantly, the intensity of Hadley cell in the monsoon (Nifio) zone in January is in negative (positive) correlation with SST of the Nifiol+2+3+4 region in the tropical mid- and east- Pacific, and is in positive (negative) correlation with SST of a C-like pattern region embaying the Nifiol+2+3+4 region. The correlation pattern in July is consistent with that in January approximately, but with weaker negative correlation especially in the monsoon zone. (4) The ENSO cycle has different effect on the Hadley cells in the monsoon zone and Nifio zone. The former weakens while the latter strengthens in E1 Nifio years, and the reverse is true in La Nifia years.