长沙一次强降水过程的雨滴谱特征分析  

Analysis on raindrop spectrum characteristics of a heavy rainfall process in Changsha

作　　者：吴亚昊 WU Yahao(Hunan Meteorological Observatory,Changsha 410118,China)

机构地区：[1]湖南省气象台,长沙410118

出　　处：《气象研究与应用》2023年第3期77-83,共7页Journal of Meteorological Research and Application

基　　金：国家自然科学基金气象联合基金项目(U2242201);湖南省科技厅重点研发项目(2019SK2161);湖南省气象局创新发展专项(2023-ZDZX05)。

摘　　要：分析2015年6月21日湖南长沙一次强降水过程的雨滴谱微物理参数特征及其随雨强的变化。结果表明,本次强降水过程主要受到高空低槽、中低层低涡切变和地面冷空气共同影响,雷达反射率因子和雨强随时间的变化基本一致,粒子数浓度与雨强、雷达回波强度与加权平均直径的时间序列之间均是高度正相关。当R≥5mm·h^(-1)时,标准化截距参数随雨强增大而显著增长但形状因子值整体上是变小的,不同雨强间隔中的多峰谱比例进一步提升,lgNw和Dm的分布趋于集中且其值增大,lgN_(w)-R的幂指数关系拟合的相关性较差。各类平均谱基本是单峰谱,随着雨强增大,峰值直径略变大,谱宽逐渐增大,各尺度档粒子浓度值显著增加。适用本次降水的Z-R关系是Z=26.67R^(1.88),尤其当雨强迅速增加时,它更能反映真实降雨分布。This article analyzes the characteristics of the raindrop spectral microphysical parameters of a heavy precipitation process in Changsha,Hunan Province,on June 21,2015,and its variation with rain intensity,showing that this heavy precipitation process is mainly affected by the combination of the upper-air trough,the low-middle-level vorticity shear,and the surface cold air.Changes of radar echo intensity and rainfall intensity with time are basically consistent.The time series of number concentration and rainfall intensity are highly correlated,as well as the time series of radar echo intensity and the weighted average diameter.The standardized intercept parameter increases significantly with the increasing rainfall intensity,while the shape factor decreases on the whole,the multi-peak spectrum proportion in different rainfall intensity intervals further increases,the distributions of lgNw and D_(m) tend to be concentrated and their values are increasing,and the fitting correlation of lgN_(w)-R is poor when R≥5 mm·h^(-1).The average raindrop spectrum is unimodal.With the increased rain fall intensity,the peak diameter increases slightly,the spectrum width increases gradually and the number concentration of each rainfall scale increases significantly.The Z-R relationship is Z=26.67R^(1.88),which could better reflect the real raindrop spectrum,especially for the rapidly increased rainfall intensity.

关 键 词：雨滴谱 标准化Gamma分布 lgNw-Dm Z-R关系 

分 类 号：P426.6[天文地球—大气科学及气象学]