空中、地面雨滴谱特征的观测分析

利用1982年7月9日宁夏银川站的一次层状云降水过程中地面、空中观测的雨滴谱资料,分析了宁夏地区层状云降水过程中地面、空中的雨滴谱特征,并对地面和空中雨滴谱进行对比。结果表明：地面雨滴谱以指数型为主（61.9%）,空中雨滴谱以多峰型为主（86.4%）;对于空中、地面雨滴平均谱,Gamma分布拟合的相关系数更高;地面雨滴谱中小滴较多,空中雨滴谱中大滴较多,可能受到碰并、蒸发、破碎的共同影响。研究地面雷达反射率因子Z、雨水含量W、雨滴数浓度N与雨强I的关系,Z-I关系和W-I关系的相关性很好,而N-I、N0-I、λ-I关系的相关性不是很好。

Observational Analysis of Raindrop Size Distributions Measured at Surface and Cloud

By using the ground-based and airborne measurements of raindrop size distributions （RSDs） during a precipitation process of stratiform cloud appearing on July 9,1982 in Yinchuan, Ningxia, the characteristics of the surface and upper RSDs are analyzed and compared. It is found that 61.9% surface RSDs exhibit the exponential distribution, whereas 86.4% upper RSDs show the multi-peak distribution. The mean surface and upper RSDs are more suitable to fit with a Gamma function. Result also reveals that the most raindrops near surface are smaller and the most raindrops at the upper are relatively bigger, which is possibly caused by the effects of coalescence, breakup and evaporation of raindrops. In addition, the correlations between the rainfall intensity （I） and the radar reflectivity （ Z）, the rainwater content（W） and the raindrops concentration（N） are established ,respectively. There is a very good correlation between I and Z,and W,but N, parameter NO and parameter λ are poor correlated to I.