夏季亚洲副热带西风急流气候特征

Climate Features of Summer Asia Subtropical Westerly Jet Stream

利用1958-2003年NCEP／NCAR月平均再分析资料以及中国160站月降水资料，较全面、细致地分析了夏季亚洲西风急流气候特征。结果表明，亚洲急流存在其南北位置、强度和沿急流Rossby波活动的变化，定义的西风急流扰动指数能较好地综合反映急流的这3种变化。沿西亚急流和东亚急流的Rossby波活动具有不同的年际和年代际变化，并受不同波列活动的影响。西亚急流Rossby波活动（WAJRA）受北大西洋涛动影响，而东亚急流Rossby波活动（EAJRA）与南极涛动有联系。西亚急流Rossby波活动影响新疆夏季降水，东亚急流Rossby波活动影响100°E以东地区降水。

Climate features of summer Asia subtropical westerly jet （SASWJ） are examined from the NCEP/ NCAR reanalysis dataset and China 160 stations monthly precipitation from 1958 to 2003. SASWJ exhibits changes of jet axis, intension and Rossby wave activity along SASWJ, and perturbation kinetic energy index along SASWJ can indicate Asia jet variability. There are different interannual and interdecadal variability between Rossby wave activities along west jet and east jet stream which are impacted by different wave trains. North Atlantic Oscillation （NAO） influences Rossby wave activities along west Asia westerly jet （RWAWAWJ）, and RWAWAWJ has intimately related to Xinjiang precipitation. There are relationships between Rossby wave activities along East Asia westerly jet （RWAWAEJ） and Antarctic Oscillation （AAO）, and RWAWAEJ is closely related to East Asia precipitation.