ANALYSES OF WIND STRUCTURE OF TYPHOON FUNG-WONG (2008) AND ITS RELATION TO PRECIPITATION REGION
Using real analysis data of 1°×1° resolution of the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR), the nondivergent wind component and irrotational wind component obtained by the harmonic-cosine(H-C) method, and the wind structure of Typhoon Fung-Wong (coded 0808 in China) in 2008 was analyzed. The results indicated that the irrotational component was advantageous over the total wind in reflecting both the changes in convergent height and the asymmetrical convergence of Fung-Wong. In Fung-Wong, the nondivergent component was larger than the irrotational component, but the latter was much more variable than the former, which was obtained only from the wind partition method. Further analyses on the irrotational component demonstrated that the location of the convergent center at lower levels was almost the same as the divergent center during the development of Fung-Wong, and its convergent level was high in its life cycle, with the most highest up to 400 hPa when it became stronger. After the typhoon landed in the provinces of Taiwan and Fujian, respectively, its convergent center at lower levels was slowly detached from the divergent center at high levels and the convergent height was also depressed from high levels to lower levels. Gradually, this weakened the intensity of Fung-Wong. This kind of weakening was slow and Fung-Wong maintained its circulation for a long time over land because of its very thick convergent height. Analyses on wind partitioning provided one possible explanation to why Fung-Wong stayed for a long time after it landed. Furthermore, the asymmetric vertical ascending motion was induced by the asymmetric convergence at lower levels. In general, when typhoons (such as Fung-Wong) land, the rainfall region coincides with that of the convergence region (indicated by the irrotational component at lower layers). This means that the possible rainfall regions may be diagnosed from the convergent area of the irrotational component. For an observational experiment on typhoons, the convergent region may be considered as a key observational region.
作 者： ZHOU Yu-shu LIU Li-ping 作者单位： ZHOU Yu-shu(Laboratory of Cloud-Precipitation Physics and Severe Storms LACS,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China)LIU Li-ping(State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,Beijing 100081,China)
刊 名： 热带气象学报（英文版） 英文刊名： JOURNAL OF TROPICAL METEOROLOGY 年，卷(期)： 2009 15(2) 分类号： P458.1.24 关键词： wind partitioning typhoon Fung-Wong structure analysis