Application Research Of Raindrop Spectrum In Different Types Of Precipitation In Shanghai

Abstract:Using raindrop spectrum data of Parsivel laser precipitation particle spectrometer, statistical raindrop characteristics of thirty-three rainstorms in Shanghai for the period March2013to February2014are analyzed.While the selected four typical rainstorms for comparative analysis are characterized by four types:stratiform, warm convective clouds, cold convective clouds, and warm mixed clouds of a tropical cyclone. The results show:1) the larger the rain rate was, the more possible of multiple peaks structure occurred,while the raindrops with diameters about0.312mm,1.187mm and2.375mm dominated in the raindrop spectrum,especially in concentration,frequency and percentage of content;2)concentration and distribution of different sizes of raindrops result in the precipitation contribution proportion,and the descending order of width of rain size spectra was cold convection, warm convection,warm mixed clouds, and stratiform precipitation;4) raindrop velocity had a positive correlation with raindrop size and rain rate. Raindrop size distributions are also compared with radar reflectivity and derived vertically integrated liquid (VIL) above different levels, rain-gauge rain rate, and cloud-ground lightning flash rate for those four selected cases above.During the period of these different types of precipitation,it had showed consistency between raindrop size distribution and other characteristics:the maximum of different sizes of drops reflect the evolution of rainfall process.The classification and evolution of raindrop size distribution are helpful to analyze the attributes and spatial distribution of water particles and differences between precipitation formation mechanism,which makes it easier to identify different types of precipitation and to compensation for the radar quantitative precipitation estimation.