祁连山北坡一次秋季对流性降水雨滴谱特征分析OA北大核心CSTPCD

This study analyzed the influence system,characteristics of the raindrop spectrum of a convective pre-cipitation process that occurred on September 21,2020,in the northern slopes of the Qilian Mountains using up-per-air and ground data,Doppler weather radar products,and Parsivel2 laser raindrop spectrometer observation data.Results demonstrated that precipitation was affected by a short-wave trough moving eastward over the pla-teau and the northern border region.Liquid water content W was consistent with rain rate R,and the correspond-ing raindrop diameter D was＜1 mm when the particle number concentration N(D)was maximum at each site,which occurs during stratiform precipitation.The raindrop diameter increased rapidly during the maximum rain intensity of convective precipitation,with the maximum diameter D being in the range of 2.75-3.75 mm at each site.The mean raindrop number concentration NT was larger at higher elevation sites than at lower elevation sites,whereas the mean mass weighted average diameter Dm was larger at lower altitude sites than at higher altitude sites.The Dm of convective precipitation was significantly larger than that of stratiform precipitation.The distribu-tions of Dm and log Nw were relatively concentrated for convective precipitation,whereas they showed larger spec-tral width for stratiform precipitation.The gamma function could better fit the average raindrop spectrum of con-vective precipitation and stratiform precipitation in the Qilian Mountains.The shape parameter µ and the slope pa-rameter λ of the gamma fitting function satisfied the good fitting relationship in convective precipitation and strat-iform precipitation.Positive fitting coefficient and exponent were observed in the relationship of Dm-R.Dm in-creased with the improvement of R and stabilized after the rain rate reached a certain value.The log Nw of strati-form precipitation changed faster with improvement of R,and the log Nw of convective precipitation increased slowly with improvement of R.The precipitation estimates of convective precipitation and stratiform precipitation were lower in the Qilian Mountains when the default Z-R relationship was used to estimate precipitation in the op-erational radar application.