摘要
微波遥感可以穿透云顶直接探测对流云内的冰态粒子分布,受冰晶粒子的强烈散射衰减作用,AMSU—B的3个微波水汽吸收波段亮温随冰粒子的增加而降低。由于探测权重高度不同,辐射传输过程中受冰粒子的散射影响也不尽相同,3个水汽通道之间存在亮温差异,这种差异与对流云的强弱密切相关。利用微波向量辐射传输模式(VDISORT)模拟了云雨粒子对微波水汽通道观测的影响.并利用2005年8月12日华北地区的对流天气过程,分析了AMSU—B通道亮温与对流强弱变化之间的对应关系。在此基础上,建立了一种利用NOAA卫星AM—SU-B水汽通道亮温差定量判识深对流云和冲顶对流云的方法。利用该方法对典型对流降水云团进行判识,结果显示,微波识别的对流云区可以较好地表征强降水的分布,其中的冲顶对流区与可见光云系的上冲云顶结构有着很好的对应。
Microwave remote sensing has a unique ability to penetrate the clouds and get the dis-tribution of ice. The brightness temperatures of the AMSU-B three channels near to the water vapor absorption line have high sensitivity to frozen hydrometeors in convective cloud systems. As the ice contents ascend, the brightness temperatures descend due to the ice scattering attenuation.Especially, the brightness temperature differences between the three channels are suggested as a criterion to detect the deep convective clouds. Based on the simulation of the influence of the water vapor, cloud and precipitation particles on the three microwave brightness temperatures, and by analyzing the convective synoptic process occurred on 12 August 2005, the relationship between the brightness temperatures and the convective intensity is studied. Furthermore, a measurable method is developed to estimate and identify the deep convective clouds and convective overshooting. This method is employed to investi- gate some typical convective systems. The results show that the convective cloud identified by AMSU-B data well corresponds to the precipitation area, and even the convective overshooting region corresponds to the overshooting clouds structure.
出处
《气象》
CSCD
北大核心
2008年第3期22-29,129,共9页
Meteorological Monthly
基金
国家高技术研究发展计划“多源卫星资料强对流监测与追踪方法研究(2006AA122106)
国家基础研究项目基金“我国南方致洪暴雨监测与预测的理论和方法研究”(2004CB418305)资助
关键词
气象卫星
对流
微波
水汽通道
meteorological satellite
convection
microwave
water vapor channel
