华东登陆热带气旋若干回波参数的分析应用

RADAR ECHO CHARACTERISTICS ANALYSIS AND ITS APPLICATION ON LANDING TROPICAL CYCLONE

新一代天气雷达在台风监测及短期临近预警中的作用越来越大,但当前CINRAD雷达针对台风的监测产品仍不能满足需求。通过对近年来登陆浙江的热带气旋雷达回波参数的分析和计算发现,监测、诊断近海台风,除了考虑回波的强度、大小、高度及结构等传统因素外,以雷达资料计算台风的最大风圈半径、切向旋转环流速度等参数,可便捷快速地分析台风的强度及影响范围;台风环平均强度(或台风环平均降水率)在登陆前后变化明显,环状平均降水主峰值的半径均呈现增大态势,主峰极值与次峰极值在量级上的差距加大更为显著。研究表明,当台风临近时,利用雷达密切监测回波的演变、及时提取和分析有关参数,对台风研究及提升台风临近预警能力都具有重要意义。

NEXRAD plays an important role in typhoon tracking and nowcasting operation. The current typhoon products from CINRAD still need improvement. This paper provides some meaningful radar echo parameters of the landing tropical cyclones around the eastern coast of Zhejiang province. Our analysis indicates that, besides the intensity, height, and structure of echo, many parameters computed from radar data can be used to analyze the typhoon intensity and affecting range quickly and conveniently. It was also found that typhoon average intensity in circle exhabits a distinct change before and after landing. The radius of the circle having maximum average precipitation shows an increasing trend. The difference in experiments between the maximum value and the sub-maximum value becomes more significant. Our study shows that monitoring echo evolution and calculating and analysing the parameters from radar data play important roles in typhoon studies and improving typhoon nowcasting skills.