摘要
该文研究PARSIVEL激光雨滴谱仪的测量误差并提出订正方法。对2014年在广东阳江的PARSIVEL激光雨滴谱仪采集的两次降水过程数据进行分析发现,雨滴下落速度V随粒径D变化与静止大气中雨滴下落末速度随粒径变化的Atlas-Ulbrich曲线分布趋势一致,但D<1 mm及D>3 mm的速度偏差较大。其主要原因是大粒径雨滴形变造成速度偏离较大,仪器测量误差造成小粒径测速偏大,激光雨滴谱仪所在高度的大气垂直运动影响雨滴下落速度。根据PARSIVEL激光雨滴谱仪测量原理,基于雨滴形变与粒径关系,给出形变订正后的Atlas-U1-brich修正曲线,并用于对小粒径测速订正。比较订正前后的雨滴谱分布,订正后的小雨滴浓度明显增加,大雨滴浓度略有减小,订正后浓度参数和斜率参数均增加,形状参数变化不明显。
The error of raindrop size distribution estimation using PARSIVEL disdrometer is carefully studied, and an error correction method is proposed. Raindrop distribution data of two kind of precipitation by PARSIVEL disdrometer at Yangjiang in 2014 are analyzed. Results show that, the measured raindrop size distribution data are in good consistency with the empirical curve from Atlas, but the velocity measurement error is large when the particle size is below 1 mm or above 3 mm. The error analysis indicates that veloci- ty measurement error of big particle is caused by deformation, while the error of small particle is caused by the instrument itself, and the vertical air motion near the disdrometer is influential for both situations.
According to the detective principle of PARSIVEL disdrometor and the relationship between the de- formation particle, a corrected Atlas-Ulbrich curve is given. The detective data of stratiform cloud precipi- tation are stable. An correction error curve of small particles is given by calculating the vertical air velocity of no less than 1 mm in diameter data from the stable precipitation, excluding the air motion in the diame- ter less than 1 mm. Small particle data are corrected, and the corrected raindrop distribution data are in good consistency with corrected Atlas-Ulbrich curve. The droplet concentration increases significantly and large drops concentration reduce slightly after correction. The intercept, slope and shape parameters of Gamma distribution of two kinds of precipitations are calculated before and after the correction, and the comparison shows that the corrected intercept parameter and slope parameter increase obviously, while the shape parameter barely changes.
出处
《应用气象学报》
CSCD
北大核心
2016年第1期25-34,共10页
Journal of Applied Meteorological Science
基金
国家自然科学基金项目(41475029)
公益性行业(气象)科研专项(GYHY201306004
GYHY201406013)
