摘要
微波遥感可以穿透云顶直接探测云内的冰粒子分布,NOAA系列卫星微波湿度计(AMSU-B)的3个水汽吸收波段对冰粒子含量的变化有着很好的响应,受冰粒子的强烈散射衰减作用,亮温随冰粒子的增加而降低。因此,可以利用3个水汽通道亮温变化判断云中冰粒子的含量。根据模拟实验结果,确定了对流云状态下各水汽通道对冰粒子的响应高度,冰粒子引起的(183.3±1)GHz通道亮温变化主要出现在300hPa(约相当于10km)以上,(183.3±3)GHz通道的亮温变化由400hPa(约相当于8km)开始,(183.3±7)GHz通道的亮温变化由450hPa(约相当于6.5km)开始。建立了利用NOAA卫星AM-SU-B水汽通道反演对流云冰水路径和冰水厚度的算法,得到的反演结果与闪电分布具有较好的一致性。其中,强的负闪发生区与高层冰粒子聚集区对应较好,而正闪和部分较弱负闪发生在中层冰粒子聚集区,与星载微波成像仪(TMI)反演可降水冰结果比较,3个通道反演冰水路径的平均均方根误差约为0.4。
The microwave remote sensing is able to penetrate clouds,and gives a clear view of the ice distributing.The Brightness Temperature（BT） of three water vapor channels（183.3±1,183.3±3,and 183.3±7 GHz）,which is from the Advanced Microwave Sounding Unit-B（AMSU-B） onboard NOAA series satellites,has high sensitivity to ice contents in convective cloud.With the ice contents enhancing,the BT descends due to the ice dispersion attenuation.Thus,this study is focused on retrievalling the cloud ice concents using the variety of BT.With the simulation experiments,the results confirm that the BT responses of the three water vapor channels initiated at different altitudes,for convective cloud systems,the BT changes caused by ice particles at 183.3±1 GHz are mainly seen above the 300 hPa,about 10 km,while those at 183.3±3 GHz and 183.3±7 GHz are about 8 km and 6.5 km,that is corresponding to the level of 400 hPa and 450 hPa,respectively.The present study derives the retrieved method for the vertical distributions of frozen hydrometeors,and computes the IWP（ice and water path） and the IWTH（ice and water thick） using satellite measurements at the AMSU-B water vapor channels.The good correspondence of the retrieved results with the high lightning area are reached by use of the methods.Strong negative lightning mainly happens over the high level ice collection area,while positive and weak negative lightning happen over the middle level.Contrasted with Total Precipitation Water（TPW） from the TRMM/TMI,the average square root error of the retrieved IWP results is about 0.4.
出处
《气象学报》
CAS
CSCD
北大核心
2011年第5期900-911,共12页
Acta Meteorologica Sinica
基金
国家公益性行业(气象)科研专项(GYHY200906002)
