秋台风“康妮”螺旋雨带特征及引发的浙江强降水分析

Characteristics of Spiral Rain Band of Autumn Typhoon“Kong-rey”and Analysis of Heavy Precipitation in Zhejiang

关键词:  康妮  螺旋雨带  锋生  地形  对称不稳定

Key words:  Kong-rey  spiral rain band  frontogenesis  terrain  symmetric instability

摘要:

利用ERA5再分析资料、地面自动站、GPM_3IMERGM降水产品、雨滴谱、黑体亮度温度以及S波段雷达等多源资料，研究秋台风“康妮”的螺旋雨带特征及造成的浙江强降水成因，结果如下：“康妮”前期台风结构紧凑、眼区清晰，强降雨集中在眼区周围，垂直风切变为偏南方向，登陆台湾省后，台风结构出现明显不对称，北侧螺旋云带发展，垂直风切变逆转为偏东方向。“康妮”北上时与西风槽结合，浙江上空为明显的锋生带和水汽辐合带。宁波降水极值点上空存在对流不稳定和对称不稳定，前期为台风倒槽内多条螺旋雨带逐渐北抬造成的暖性降水，后期转为冷性降水，受喇叭口地形狭管效应和迎风坡强迫抬升影响，强降雨云团稳定少动，有明显列车效应。台州降水极值点上空主要为对称不稳定，基本为台风倒槽内的暖性降水。对称不稳定是两个极值点降水加强的重要因素。降水强度与粒子尺度有关。

Abstract:

By using ERA5 reanalysis data, ground automatic station, GPM_3IMERGM precipitation, raindrop spectrum, black body temperature (TBB), S-band radar and other multi-source data, the spiral rain band characteristics of autumn Typhoon "Kong-rey" and the causes of heavy precipitation in Zhejiang are studied. The results show that in the early stage of "Kong-rey", the typhoon had a compact structure and clear eye area, heavy rainfall concentrated around the eye area, and the vertical wind shear was in the southerly direction. After landing in Taiwan Province, the typhoon structure showed obvious asymmetry, the spiral cloud belt on the north side developed, and the vertical wind shear reversed to the easterly direction. When "Kong-rey" moved north, it combined with the westerly trough, which resulted to obvious frontogenic zones and water vapor convergence zones over Zhejiang. There were convective instability and symmetrical instability over the precipitation extreme point in Ningbo. In the early stage, the warm precipitation was caused by the gradual northward rise of several spiral rain bands in the typhoon trough, and then it turned to cold precipitation. Affected by the narrow tube effect of the trumpet topography and the forced lifting of the windward slope, the heavy rainfall clouds were stable and less moved, with obvious train effect. Symmetric instability was over the precipitation extreme point in Taizhou , and the precipitation was basically warm in the typhoon trough. Symmetric instability was an important factor of precipitation intensification at two extreme points. Precipitation intensity is related to particle size.