利用偏角方差技术分析2015年西北太平洋超强台风全生命史过程演变特征

Detecting the Intensity Evolutions of Northwest Pacific Super Typhoons in 2015 Using Deviation Angle Variance Technique

摘要: 本文利用偏角方差技术(Deviation angle variance technique: DAV-T)从热带气旋(Tropical cyclone: TC)系统亮温分布的对称化程度的角度，分析了2015年西北太平洋地区13个超强台风整个生命史过程中结构和强度的演变特征。结果表明，在热带气旋不同强度阶段其系统内深对流云团的轴对称化程度不同，相对应的DAV极小值(Map minimum value: MMV)随系统强度增大而出现明显减小，同时整体DAV分布也呈现由不规则分布向围绕热带气旋环流中心的近圆形结构变化的特征。然而在热带气旋系统处于热带低压及以下的低强度时期，且存在较大尺度非闭合深对流云团时，MMV量值较低但其位置则偏离系统环流中心出现在对流最旺盛的区域，此时MMV所在位置与环流中心的相对距离(Relative Distance: RD)可作为判断MMV所反映深对流云团对称化中心是否位于热带气旋环流中心的重要参考。综上所述，MMV的量值大小和位置对于热带气旋强度和位置的预报具有重要的指示意义。

Abstract: This paper analyzes the intensity evolutions of northwest Pacific super typhoons in 2015 using the Deviation angle variance technique (DAV-T) from the perspective of symmetry of the brightness temperature distribution in the tropical cyclone (TC) system. It is found that with the increase of TC intensity, the axisymmetry of deep convective clouds shows different characteristics; meanwhile, the minimum value of DAV map (MMV) decreases obviously and the DAV distribution change from the irregular to near-circular structure that around a TC circulation center. However, when the in-tensity of TC is below the tropical depression intensity as well as there is a large-scale non-closed deep convective clouds, the MMV would at a low level but its position would locate at the most convective area which deviates from the center of the system circulation and the relative distance (RD) between the location of the MMV and the circulation center can be used as an important reference for judging whether the MMV reflects the center of axisymmetry of the deep convection cloud agree with the TC circulation center. In summary, MMV is an important indicator for the prediction of TC intensity and position.