西北太平洋热带气旋的年际和年代际变化及其与南亚高压的关系

THE INTERANNUAL AND INTERDECADAL VARIATIONS OF TROPICAL CYCLONES IN THE NORTHWEST PACIFIC AND ITS RELATIONSHIP WITH THE SOUTH ASIA HIGH

利用 1 949～ 1 996年 48年西北太平洋热带气旋 (TC)的年个数资料和 1 95 8～ 1 997年 40年南亚高压 (SAH)特征参数的月平均资料 ,讨论了西北太平洋TC年个数的年际、年代际变化、年个数周期和周期能量等特点及其与SAH特征参数的关系和异常TC年前期SAH环流场和 1 0 0hPa高度场的特征。结果表明 ,西北太平洋TC具有明显的年际和年代际变化 ,前期SAH对当年TC频数有一定影响 ,SAH中心位置偏北、偏西 ,中心强度偏弱时 ,当年TC偏多 ,反之 。

By use of annual numbers of the Tropical Cyclone (TC) in 48 years (1949-1996) and monthly mean characteristic parameters of the South Asia High (SAH) in 40 years (1958-1997), the features of interannual and interdecadal variations as well as the period and period energy of the annual TC numbers are analyzed. Furthermore, the relationships between the annual TC numbers and the characteristic parameters of SAH are depicted, and the features of the SAH circulation and the 100 hPa height field in prior time in TC abnormal years are also composed and discussed. The results show that the TC numbers in Northwest Pacific have obvious interannual and interdecadal variations, and that the SAH in prior time has a certain influence on the TC frequency in a year. When the center of the SAH goes more westward and northward, and its center intensity is weaker, the TC numbers in the year would be more, and vice versa.