多平台热带气旋表面风场资料在台风结构分析中的应用

Applications of MTCSWA Data to the Characteristic Analysis of Tropical Cyclone Structure

本文利用2007-2014年美国海洋和大气管理局的多平台热带气旋表面风场资料（Multiplatform Tropical Cyclone Surface Wind Analysis,MTCSWA）对西北太平洋和南海区域内共210个编号热带气旋进行了统计分析。结果表明,MTCSWA资料中的最大风速（VMAX）相较最佳路径强度偏弱10%～15%,对于较弱的台风存在一定的高估。最大风速半径（RMAX）与台风强度之间存在一定的线性关系且在不同区域具有不同的分布特征。由于RMAX与台风的强度有关,对于强度达到强热带风暴以上级别的各个海区内台风其结构差异不明显,而对于强度较弱的台风（强热带风暴以下）其最大风速半径具有一定的区域分布差异。对台风各级风圈半径的分析结果显示：7级风圈半径通常是东部大于西部,而10和12级风区半径没有这种现象。利用MTCSWA的内核区高分辨率对1215号超强台风布拉万分析发现,在其内外眼墙置换过程中,内外眼墙之间的距离（R2-R1）逐渐减小,内眼墙的风速（V1）逐渐减小,而外眼墙的风速（V2）逐渐增加,且在此过程中伴随有台风强度的短暂波动。最后结合MTCSWA资料和数值预报讨论了一种台风结构参数的客观估计方法,其检验结果表明该方法对RMAX和各级风圈半径均有一定的估计能力。

Based on Multiplatform Tropical Cyclone Surface Wind Analysis （MTCSWA） data from NOAA/NESDIS during 2007-2014, statistic characteristics of 210 named TCs’structures in the North Western Pacific and the South China Sea are analyzed. Compared with the maximum wind speed （VMAX） from CMA best tracks, the VMAXfrom MTCSWA is 10%-15 % smaller on average. Overestimation, especially for weaker TCs, is observed. Statistical relationship is provided between radius of maximum wind speed （RMAX） and VMAX, and the density distributions of RMAX in different regions are calculated. For those TCs stronger than STS, the density distributions show no regional differences while the less intensified groups show obvious structure distributions in the North Western Pacific, the Northern and Eastern China Seas and the South China Sea. Especially, in the South China Sea, the distribution difference gets much broadly from 50 to 100 km. By analyzing the distributions of four quadrants, the eastern parts of R34 is comparably larger than that in western parts, but there is no such a character in both R50and R65. From the case study of Super TY Bolavan （1215）, an eye wall replacement and inner core structure change can be observed. During that ERC period, the distance between inner and outer eye wall （R2-R1） is reduced along with V1’s decreasing and V2’s increasing. Meanwhile the original intensity shows temporary fluctuation.