基于雨强分级的乌鲁木齐雨滴谱特征研究  

Microphysical Characteristics of Raindrop Size Distribution Based on Rain Intensity in Urumqi

作　　者：杨涛 张祖熠 杨莲梅[1,2,3] YANG Tao;ZHANG Zuyi;YANG Lianmei(Institute of Desert Meteorology,China Meteorological Administration,Urumqi 830002,China;Xinjiang Cloud Precipitation Physics and Cloud Water Resources Development Laboratory,Urumqi 830002,China;Field Scientific Observation Base of Cloud Precipitation Physics in West Tianshan Mountains,Urumqi 830002,China)

机构地区：[1]中国气象局乌鲁木齐沙漠气象研究所,新疆乌鲁木齐830002 [2]新疆云降水物理与云水资源开发实验室,新疆乌鲁木齐830002 [3]西天山云降水物理野外科学观测基地,新疆乌鲁木齐830002

出　　处：《沙漠与绿洲气象》2022年第4期64-71,共8页Desert and Oasis Meteorology

基　　金：国家重点研发计划项目(2018YFC1507102);中央级公益性科研院所基本科研业务费专项资金项目(IDM2022001)。

摘　　要：利用乌鲁木齐PARSIVAL激光雨滴谱仪2012-2013年观测资料,对春、夏、秋季不同雨强降雨的雨滴谱微物理特征参量及其随时间演变特征、Gamma函数拟合、关系等进行研究。结果表明:(1)乌鲁木齐降雨以小粒子为主,大雨强降雨的6种特征直径最大,中雨强降雨次之,小雨强降雨最小。雨滴数密度主要来自于小雨滴(直径<1 mm),大雨滴(直径>3 mm)是雨强的主要贡献者,中雨滴(直径1-3 mm)是含水量和雷达反射率因子的主要贡献者,雷达反射率因子受雨滴尺寸影响很大。(2)小雨强降雨各微物理参量比较稳定,变化幅度不大,大雨强降雨则变化剧烈,出现多峰型,中雨强降雨介于二者之间。大雨强降雨的谱宽和峰值浓度最大,小雨强降雨最小,中雨强降雨介于二者之间,小雨强降雨的拟合谱具有明显的季节差异性;秋季峰值浓度最大,这与秋季多大风天气有关。(3)Gamma拟合参数 Λ-μ关系与粒子尺寸有关,可以用二项式进行描述。拟合出的Z-I关系系数均小于目前常用的Z=300I^(1.4)关系系数,因此,利用Z=300I^(1.4)关系在乌鲁木齐进行降雨定量估测研究时会造成对降雨强度的高估,回波强度越大,高估越明显。夏季大雨强降雨无法拟合出相关系数比较高的Z-I关系,这与乌鲁木齐大雨强降雨具有强度大、时间短、随时间变化迅速的特点有关。Based on the measurements from PARSIVAL laser raindrop spectrometer in Urumqi from 2012 to 2013,the microphysical characteristic parameters of raindrop size distribution based on different rain intensity in spring,summer and autumn,and their evolution characteristics with time,Gamma function fitting and relationship are studied in this paper.It shows that:(1)The precipitation in Urumqi is dominated by small particles,and the six characteristics diameters of heavy rainfall are the largest,followed by moderate rainfall,and the light rainfall is the smallest.Raindrop number density mainly comes from small raindrops(diameter<1 mm),large raindrops(diameter>3 mm)are the main contributors to rain intensity,while medium raindrops(diameter 1-3 mm)are the main contributors to water content and radar reflectivity factor,and radar reflectivity factor is greatly affected by raindrop size.(2)The microphysical parameters of light rainfall are relatively stable with little change,while heavy rainfall varies dramatically with multi-peak pattern,and moderate rainfall is between the both.The spectral width and peak concentration of heavy rainfall are the largest,while that of light rainfall is the smallest,and that of moderate rainfall is between them.The fitting spectrum of light rainfall has obvious seasonal differences.The peak concentration in autumn is the largest,which is related to the windy weather in autumn.(3)The Gamma fitting parameter relationship Λ-μ is related to the particle size and can be described by a binomial equation.The fitted Z-I relationship coefficient is smaller than the commonly used Z=300I^(1.4) relationship.Therefore,the use of the Z=300I^(1.4) relationship in quantitative estimation of rainfall in Urumqi will lead to an overestimation of rainfall intensity.The greater the echo intensity is,the more obvious the overestimation would be.The heavy rainfall during summertime cannot fit the relationship well due to the characteristics of heavy rainfall in Urumqi,which is high intensity,short time and rapid

关 键 词：乌鲁木齐 雨滴谱 微物理参量 GAMMA分布 

分 类 号：P426.6[天文地球—大气科学及气象学]