An interdecadal change of tropical cyclone activity in the South China Sea in the early 1990s
An interdecadal change of tropical cyclone activity in the South China Sea in the early 1990s
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DOI：
10.1007/s00343-012-1258-9
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发表时间：
2012-11
影响因子：
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通讯作者：
Lei Yang;Yan Du;S. Xie;Dongxiao Wang
中科院分区：
文献类型：
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作者：
Lei Yang;Yan Du;S. Xie;Dongxiao Wang
1979-2008年南海热带气旋生成在1993年前后经历了一个年代际变化。在1994-2008年期间，从5月到9月，在南海总共形成了55个TC，大约是1979-1993年期间的两倍（27）。在TC高峰季节（JAS的7月至9月），1994-2008年有43个TC，但1979-1993年期间只有17个。特别是在7月份，1994-2008年期间成立了13个TC，但1979-1993年期间没有。热带气旋数量的变化与大气和海洋关键环境条件的变化有关。与1979-1993年相比，1994-2008年副热带高压明显减弱，位置偏东。在前期，副高的增强导致了下沉气流，抑制了热带气旋的形成。在后期，垂直风切变和向外长波辐射都减弱。中层（850-500 hPa）湿度和相对涡度较高。海表温度和上层热含量也较高的地区。所有这些因素都有利于TC在后期的形成。1994-2008年期间，热带气旋生成的年代际变化导致华南地区登陆热带气旋增多，从而导致华南地区降水的突然增加。
Tropical cyclone (TC) genesis in the South China Sea (SCS) during 1979–2008 underwent a decadal variation around 1993. A total of 55 TCs formed in the SCS from May to September during 1994–2008, about twice that during 1979–1993 (27). During the TC peak season (July–September, JAS), there were 43 TCs from 1994–2008, but only 17 during 1979–1993. For July in particular, 13 TCs formed from 1994–2008, but there were none during 1979–1993. The change in TC number is associated with changes of key environmental conditions in atmosphere and ocean. Compared to 1979–1993, the subtropical high was significantly weaker and was displaced more eastward during 1994–2008. In the former period, a stronger subtropical high induced downward flow, inhibiting TC formation. In the latter period, vertical wind shear and outgoing longwave radiation all weakened. Mid-level (850–500 hPa) humidity, and relative vorticity were higher. Sea surface temperature and upper layer heat content were also higher in the area. All these factors favor TC genesis during the latter period. The decadal change of TC genesis led to more landfalling TCs in Southern China during the period 1994–2008, which contributed to an abrupt increase in regional rainfall.