摘要
利用2012年10月19日OTT-Parsivel激光雨滴谱仪在南海地区获取的一次对流云降水资料,对降水的微物理参量、平均雨滴谱和速度谱分布特征进行分析。结果表明:降水中直径小于1 mm的小粒子所占比例非常大,直径较大粒子也频繁出现,最大直径接近10 mm,大粒子对降水强度、含水量、雷达反射率因子贡献很大;对平均谱进行Gamma分布最小二乘、阶矩法拟合和对数正态分布拟合,三种方法均较好表示谱的分布,但对数正态分布拟合有着明显优势(尤其在小滴端),且拟合相对误差在三者中最低,Gamma拟合的参数μ、λ关系均能很好地用二次函数表示;速度谱分布较接近Atlas-Ulbrich的实验结果,且直径小于0.687 mm时,粒子降落速度明显大于实验值,雨滴直径越小偏大越明显,同时用Atlas-Ulbrich与Gunn-Kinzer的实验曲线形式对速度谱进行拟合,两者的拟合相对误差平均值分别为9.17%和5.87%。
The data of a convective cloud rain measured by the OTT - Parsivel optical disdrometer on October 19, 2012 in the South China Sea was used to analyze the characteristics of the microphysical parameters, average raindrop size and raindrop velocity distributions. The results show that particles with the diameter less than 1 mm take up the vast majority, meanwhile big particles with the maximum diameter of about 10 mm contribute greatly to rain rate, moisture content and radar reflectivity. To fit the average raindrop size distribution, the least square method and the moment method of Gamma distribution and lognormal law method were used, all of which have satisfactory effects, but the lognormal distribution method is superior to the other two methods with the lowest relative error, especially for the small droplets. The Gamma fitting parameters Jl and .A. can be well presented by quadratic functions. The raindrop velocity distribution is close to the experimental result by Atlas and Ulbrich. The final speed of raindrops with the diameter less than 0.687 mm is larger than the above-mentioned experimental result. The smaller the diameter, the greater the difference will be. The average relative errors of the fitting equations are 9.17% for the experimental fitting curve form got by Atlas-Ulbrich and 5.87% by Gunn-Kinzer.
出处
《热带气象学报》
CSCD
北大核心
2014年第1期181-188,共8页
Journal of Tropical Meteorology
基金
国家973全球变化重大科学研究多尺度气溶胶综合观测研究(2010CD950804)
国家公益行业研究专项(201206051-5)共同资助
关键词
南海
对流云降水
雨滴谱
微物理特征
速度谱
South China Sea
convective cloud rain
raindrop size distribution
microphysical characteristics
raindrop velocity distribution
