2014年两类南海生成台风组织化特征对比分析

Organization Features Comparison of Different Typhoons in the South China Sea in 2014

摘要: 本文选取了2014年两个具有相似生成和移动过程的南海生成命名和南海生成未命名的典型台风个例，对其生成，成熟、消亡三个阶段的组织化特征进行分析，通过比较偏差角方差(Deviation Angle Variation, DAV)技术计算结果与最佳路径资料信息以及风云云图分布特点，揭示了南海台风生命史全过程的精细化结构分布及其与路径强度变化的关系。研究表明，DAV表征的是系统内具有一定范围的深对流云团的轴对称程度，是台风内深对流组织化的量化体现。DAV极小值(Map Minimum Value, MMV)则表征系统内深对流云团轴对称化的最高程度及其中心位置。因此，当深对流云团呈环状或螺旋状分布时，MMV位置能够较好地指示环流中心所在。同时MMV量值大小与强度变化呈现明显反比关系，尤其滤去高频变化后的MMV变化与系统强度变化趋势匹配度更高。然而当深对流云团出现明显非闭合特征时，MMV所在位置总是趋向于局地对流最旺盛的区域，这使得在MMV位置与台风路径产生较大偏差，同时量值与强度的联系也不紧密。此外，地面摩擦和斜压环境场会使得系统内深对流云团的非对称结构明显，从而影响其结构与强度之间的关系。

Abstract: In this paper, two typhoons in the South China Sea, one named case and one unnamed case, with similar evolution process have been chosen to analyze their organization features in genesis, development and dissipation stages. By comparing the deviation angle variation (DAV) with the best track data from China Meteorology Administration (CMA-BST) and satellite images from Fengyun, it shows the distribution and value of DAV can quantize the symmetry of deep convections (DCs) in typhoon. The map minimum value (MMV) of DAV can identify the degree of DCs’ organization and the center of organized DCs. When DCs appear to be ring-shape or spiral-shape, the locations of MMV can be the marker of typhoon center and their values appear to be inversely related to the typhoon intensity. The relation becomes significant if filtering the high frequency signal of MMV value in time series. However, when the DCs obviously appear non-closed shape, the locations of MMV always accord to the region where the DCs are strongest in typhoon system, which may result in the deviation between MMV location trajectory and typhoon path. Then the relation of MMV value and typhoon intensity is reduced. In addition, land friction and baroclinic environment may reinforce the asymmetric distribution of DCs, which also reduce the relation of its structure to typhoon intensity.