对流性降水云微波辐射特性  

Radiative Characteristics of Convective Precipitating Cloud

作　　者：王小兰[1,2] 程明虎[3] 周凤仙[4] 

机构地区：[1]中国气象科学研究院,北京100081 [2]中国科学院研究生院,北京100049 [3]中国气象局气象探测中心,北京100081 [4]中国科学院大气物理研究所,北京100029

出　　处：《应用气象学报》2009年第3期321-328,共8页Journal of Applied Meteorological Science

基　　金：林业科技支撑计划(2006BAD03A16);国家高技术研究发展计划(2007AA061901)共同资助。

摘　　要：结合MM5模式和三维微波辐射传输模式,对2003年7月9日宜昌地区一次典型的中尺度降水中心的对流性降水云微波辐射特性进行研究。结果表明:MM5模式模拟的降水量和落区与实况一致,模拟的水凝物廓线也与TMI反演值接近,85.5 GHz通道辐射亮温与TMI实测情况相近。85.5 GHz通道亮温与地面雨强相关性很弱,受云中云冰和雪花的散射降温作用显著,由于其他粒子的综合作用以及斜角观测造成的位置偏移,霰粒子对该通道亮温散射作用不明显。19.35 GHz通道亮温随雨强增加先升温后降温;与霰粒子含量表现出明显的负相关关系。37.0 GHz通道亮温随雨强的增加而降温,雨强大于20 mm/h后达到饱和,主要受雨水降温作用影响。倾斜观测比天顶垂直观测产生更低的亮温低值中心,且频率越高,低值中心的偏移越严重。Radiative characteristics of convective precipitating cloud can be used for the classification of convective/stratiform precipitation and for the algorithm to retrieval the rain rate from brightness temperature observed by satellite remote sensors. The typical convective cloud system in Yichang area on 9 July 2003 is simulated with MM5 model and its upwelling radiative brightness temperature is simulated with Monte-Carlo 3D microwave radiative transfer model. The columnar precipitation simulated by MM5 model shows consilient with that observed by rain gauges. As for the cloud microphysical particles, it is found that except for the cloud ice, the contents of the cloud water, precipitable water and precipitable ice particles from the MM5 are nearly equivalent to that retrieved from TMI data. The simulated Tb85V from M-C model also indicates similar distribution with the observed by TMI. Tb85 is sensitive primarily to the precipitated ice and snow content in clouds. The weak correction between Tb85 and the surface rain rate is found. Given the rain rate less than about 5 mm per hour in this case, Tb19 rises since the rain rate increases. However it descends with the rain rate increasing while the rain rate is over 5 mm per hour. Because of the notable intercorrelation between Tb19 and graupel content, it can be regarded as the indicator of surface rain rate in the strong convective center, at least as the estimator of columnar precipitated water content at upper layers. The feeble correlation between Tb85 and graupel columnar content happens because the upwelling Tb85 is synthetically affected by the various hydrometers such as the emission from cloud water and the scattering from ice particles, in addition the shift caused by oblique FOV. Tb37 has obvious correlation with the surface rain rate when it is less than 20 mm per hour and is saturated when the rain rate is over 20 mm per hour. Cloud water and precipitated rain in the convective cloud play roles on Tb37. The Tb at each channel shows the synthetical resul

关 键 词：MM5模式 辐射传输模式 辐射特性 

分 类 号：P422[天文地球—大气科学及气象学]