Development of an Algorithm for Precipitation over the Global Land by Using Space-based Microwave Radiometer

本研究旨在为利用天基微波辐射计开发全球陆地降水算法奠定基础。监测土地。利用地表发射率和地表温度作为大气辐射传输模型的边界条件，研究了2002年推出的先进微波扫描辐射计（AMSR和AMSR- e）的算法。首先考虑了土壤层的消光效应和植被层的吸收辐射效应，建立了基于物理的辐射传输模型。然后，提出了一种利用卫星传感器数据的检索算法。通过在协调增强观测项目（CEOP）蒙古参考站点的验证，获得了较好的算法精度。因此，将该算法应用于AMSR-E，生成了蒙古土壤湿度数据集。第二步，利用微波辐射传输模型开发了一种反演大气参数“综合云液态水含量”和“雪率”的算法，并将其应用于2003年1月在福井进行的AMSR/AMSR- e验证活动中获得的实验数据。从对辐射传输的四个组成部分的分离中获得的见解开始，进行了进一步的计算，以获得不同频率下的亮度温度之间的关系-这些频率要么在当前的卫星平台上使用，要么在福井实验中使用-以及要观察的大气参数。基于这些结果，开发了一种基本算法，并将其应用于实验数据。与地面测量数据的比较在某些情况下显示出良好的一致性，而在其他情况下，两种方法之间似乎没有相关性。

This research targeted to develop bases for development of an algorithm for precipitation over the global land by using space-based microwave radiometers.To monitor the land. surface emissivity and land land surface temperature as the boundary conditions of the radiative transfer model in atmosphere effectively, an algorithm for the Advanced Microwave Scanning Radiometers (AMSR & AMSR-E) launched in 2002 was developed in this research. A physically based radiative transfer model was developed by considering the effects of extinction in soil layer and absorption and radiation in vegetation layer at first. Then, a retrieval algorithm by using the satellite sensor data. A good accuracy of the algorithm is obtained through the algorithm validation in the Mongolia reference site of the Coordinated Enhanced Observation Project (CEOP). Consequently, a soil moisture data set is generated in Mongolia by applying the algorithm to the AMSR-E.As the second step, an algorithm for retrieval of the atmospheric parameters 'integrated cloud liquid water content' and 'snow rate' was developed using a microwave radiative transfer model and its application to experiment data obtained during the AMSR/AMSR-E validation campaign in Fukui in January 2003. Starting from the insights gathered from the separation of the four components of radiative transfer, further calculations were carried out, in order to obtain relations between the brightness temperatures at different frequencies -which are either in use on current satellite platforms or were used during the Fukui-experiment -and the atmospheric parameters to be observed. Based on these results, a basic algorithm was developed and applied to experiment data. The comparison with ground based gauge data shows good agreement for some cases while there seems to be no correlation between the two methods in others.