【摘要】 基于 1980～ 1997年 85 0hPa逐日NCEP/NCAR再分析资料讨论了亚洲赤道地区 (0°～ 5°N)大气动能的纬向传播特征。结果表明 ,在亚洲季风区内 ,赤道地区大气动能 (K)的最强中心位于 75°～ 90°E ,次强中心在索马里急流区 (5 0°E附近 )。在 0°～ 5°N ,90°E以东 ,平均的大气动能扰动和赤道上经向风扰动主要起源于西太平洋 ,并向西经南海传播到孟加拉湾。而在孟加拉湾动能中心与索马里急流区之间 ,动能传播方向比较复杂。以上事实说明赤道地区东亚季风系统确实是存在的 ,与印度季风系统中扰动的传播方向不同 ,东亚季风系统中动能和经向风扰动在东西方向上主要受西太平洋的影响。在亚洲赤道季风区 ,这两个系统的交界处约在 95°～ 10 0°E附近 ,比过去界定的偏西 5～ 10个经度。更多还原

【Abstract】 Based on the daily NCEP/NCAR reanalysis dataset from 1980 to 1997, the zonal propagation of 850 hPa kinetic energy ( K ) and meridional wind ( v ) at the equatorial region averaged at (0°-5°N) are examined respectively. Results show that the strongest center of K in the tropical Asian summer monsoon region locates over 75°-90°E, with the secondary over Somalia low level jet channel, i.e., about 50°E. East to 90°E, disturbances of both K and v are observed mainly coming from the western Pacific Ocean and propagating westward to the Bay of Bengal passing through the South China Sea. But the propagation directions of both K and v are rather disorderly between the Bay of Bengal and the Somalia low level jet channel. Therefore, the East Asian summer monsoon and the Indian summer monsoon are different in the propagation features of the disturbances of K and v . Above facts indicate that, East Asian monsoon system exists undoubtedly even at the equatorial region, and quite distinct from the Indian monsoon system, it is mainly affected by the disturbances coming from the tropical western Pacific rather than from the Indian monsoon region. The boundary of the two monsoon systems is around 95°-100°E, which is more westward than the counterpart as proposed in earlier studies by 5-10 degrees in longitude.更多还原