2011年台风“南玛都”不同阶段降水结构特征

Precipitation Structural Characteristics in Different Stages of Typhoon ‘Nanmadol' in 2011

利用TRMM卫星资料和NCAR／NCEP再分析资料，分析了2011年11号“南玛都”台风不同阶段的降水特征及其在台湾岛南部登陆后减弱阶段的热力和动力结构特征。结果表明：1）“南玛都”台风的降水分布显著不对称，台风眼壁区降水最强烈，且以对流云降水为主，但层状云降水对总降水量的贡献作用大于对流云降水，其他类型云在台风发展过程中对总降水量的贡献作用很小。台风发展过程中，降水云中3种不同相态的粒子含量表现为：雨水粒子含量最高，冰水粒子次之，云水粒子最少。在台风的初生和减弱阶段，降水范围小，强降水集中在台风环流的西南侧，其他方位上降水零散，且强度较弱。但在成熟阶段台风结构清楚完整，强降水集中在台风中心东南侧。2）“南玛都”台风降水云系在垂直方向呈明显的柱状结构，可伸展到对流层10kin左右的高度，但强降水回波集中在〈5km的高度上；回波中心较低，集中在2～4km高度处。3）对“南玛都”台风在台湾岛登陆后减弱阶段的分析表明，台风的暖湿中心随高度向西南方向倾斜，潜热释放在对流层中层约5km高度处累积，再加上对应高度上的暖心结构明显，以及登陆后地面摩擦造成的辐合加强，是台风登陆后产生降水的主要原因。同时在不稳定的大气层结中，伴随着台风西南侧从低空到高空较强的气旋性环流，以及对流层顶强烈的辐散流出，这种大气流场的空间结构有利于台风西南侧降水强度的增加。

Based on the TRMM satellite data and NCAR/NCEP reanalysis data, this paper analyses the variations of precipitation characteristics of Typhoon ＇Nanmadol＇ in 2011, especially its thermal and dynamic structures in its weakening phase after landing on the south part of Taiwan Island. The results show that： 1） The rainfall distribution of ＇Nanmadol＇ is significantly asymmetric, and severe precipitation occurs at the eye-wall region, which mainly resulted from the convective cloud, but stratiform cloud contributes much to the total rainfall of typhoon than convective clouds. Within the four kinds of particles in the clouds, the content of cloud-water particles is the lowest, followed by ice-water, and the content of rain-water particles is the most than any others. Around the typhoon, precipitation mainly occurs in its southwest direction during the stage of infancy and weakening, but in the southeast direction in maturity stage with a more clear and complete structure. 2） The precipitation cloud of ＇Nanmadol＇ is columnar in the vertical direction and can be extended up to about 10 km, while the heavy rainfall echo concentrates below the height of 5 krn, especially at the level of 2-4 km. 3） After its landing, severe precipitation mainly occurs in its southwest direction, but in other orientations there is scattered and weak rainfall. The warm-moist core of typhoon inclines towards southwest with the height. At the same time the strong latent heat releases at the middle troposphere, which is about the height of 5 km. In one word, the air flows in the typhoon from the lower troposphere with strong convergence, and flows out it at the level of the tropopause with divergence in the unstable atmospheric stratification, which is benefit to the formation of heavy rainfall in the southwest part of typhoon center.