摘要
基于机载双频测雨雷达外场校飞试验中获取的有效降水测量数据,利用Ku波段的雨衰系数和等效雷达反射率因子的比值估算了雨滴谱分布参数。在此基础上,通过米散射模拟计算了Ka波段在该滴谱分布下的等效雷达反射率因子,并和机载Ka波段衰减订正后的等效雷达反射率因子进行了比对。结果表明:两者的廓线基本重合,相关系数超过0.95,两部雷达探测的目标物一致,测量的雷达反射率因子的差异主要是由雷达频率的不同所引起的后向散射以及衰减的不同所造成的,波束匹配精度较高。此外,单频滴谱参数的估计依赖于单频衰减订正的精度。机载雷达外场试验中探测的都是弱降水,Ku波段衰减订正不会存在太大的误差,估计的滴谱较为可靠。必须指出的是,精确的参数估计仍然要借助双频雷达的反演方法。
Taking the observed valid rain data in the airborne dual-frequency rain radar filed campaign on 2010 October 11 the drop size parameters is estimated by using the ratio of Ku band rain attenuation coefficient and effective radar reflectivity factor.Based on it,the effective radar reflectivity factor of Ka band is computed simulativcly and compared with the effective radar reflectivity factor detected on the airborne Ka band after attenuation correction.As a result, the simulated and observed Ka band radar reflectivity factor profile is almost coicident with each other and the correlation coefficient is above 0.95.What＇s more,the detected object is the same for the dual-frequency radar and the difference of measured radar reflectivity factor between Ka and Ku is caused by the difference of radar frequency, suggesting a good beams match situation.In addition,the estimated drop size parameters by single frequency relied on the precision of attenuation correction.Fortunately, the rain detected by the airborne radar is weak, and the attenuation correction of Ku band is reasonable and the drop size parameters are reliable.But,it is noticed that the drop size parameters estimation with a high precision still needs the dual-frequency rain retrieval method.
出处
《气象学报》
CAS
CSCD
北大核心
2013年第3期547-554,共8页
Acta Meteorologica Sinica
基金
公益性行业(气象)科研专项项目(GYHY201006050)
中国科学院数字地球重点实验室开放基金项目(2011LDE001)
国家自然科学基金项目(41201360)
关键词
机载双频降水雷达
滴谱分布
米散射
Airborne dual-frequency rain radar, Drop size distribution, Mie scatter
