延 昊,吴门新, 刘桂青, 李 娟. 2006. 利用MODIS的多通道信息估计中纬度降雨[J]. 气象学报, 64(2):205-210, doi:10.11676/qxxb2006.020
利用MODIS的多通道信息估计中纬度降雨
OVERLAND RAINFALL ESTIMATES IN MIDLATITUDE BY USING MODIS MULTI CHANNELS
投稿时间:2005-04-11  修订日期:2005-09-16
DOI:10.11676/qxxb2006.020
中文关键词:  降雨估计,MODIS,多通道信息,AMSRE
英文关键词:Rainfall estimates, MODIS, Infrared/visible channels, AMSE-E.
基金项目:国家自然科学基金项目(30370814)和国家气象中心《利用卫星降水估计资料计算淮河流域的面雨量》项目,上海台风研究基金《基于多源遥感探测资料的热带气旋降水判别估计》项目资助。 作者简介:延昊,1973年生,男,博士,副研究员。主要从事大气参数和生态系统的遥感研究。
作者单位
延 昊 中国气象局国家气象中心北京100081 
吴门新 中国气象局国家气象中心北京100081 
刘桂青 中国气象局国家气象中心北京100081 
李 娟 中国气象局国家气象中心北京100081 
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中文摘要:
      基于同一Aqua卫星上的中分辨率成像光谱仪MODIS的多通道数据和被动微波辐射计AMSR E的微波数据,文中研究了由MODIS的热红外亮温 T B11μm 和可见光通道反射率 R 0.65μm 估计中纬度降雨的方法。首先利用MODIS 的 R 0.65μm >0.8和T B11μm<270 K检测降雨云,并利用一个非线性函数估计雨强。同时,利用AMSR-E微波降雨产品对MODIS降雨估计进行了验证,发现降雨范围和雨强基本一致, 在2°格点上相关系数的平方达到 0.82 ,这启示MODIS降雨估计可以达到与被动微波降雨估计相近的精度。与自动雨量站观测数据的检验也取得较好的效果。
英文摘要:
      This paper describes a method of rainfall estimates in midlatitude based on Moderate Resolution Imaging Spectroradiometer (MODIS) 11 μm infrared temperature TB11μm and 0.65μm visible reflectance R 0.65μm. Generally, rain cloud is higher than non rain cloud in altitude and its temperature is lower than that of non rain cloud. It means 11 μm infrared channel carries information of rain cloud and non rain cloud, which can be used to detect rain and estimate rainfall. Moreover, rain cloud has a big cloud optic thickness related with a big R 0.65μm Thus, T B11μm and R 0.65μm should be combined to estimate rainfall. The method, denoted MODIS multi-channel technique, detects rain cloud according to thresholds of MODIS R0.65μm >0.8 and T B11μm<270 K, in which high visible threshold of R 0.65μm is able to screen out cirrus due to its transparent feature in visible channel. Then a nonlinear function of R 0.65μm and TB11μmcompletes the rain rate estimation. More specifically, different function of R0.65μm for different T B11μm is further used for rainfall estimation upon calibration with AMSR-E rain rate products. The technique was tested for one Asia case and validated with AMSR-E passive microwave rainfall estimates and rain gauge data from May to July 2005. The result shows that rain estimates of MODIS agrees well with AMSR-E microwave estimates with a correlation coefficient R 2 of 0.8 at a spatial scale of 2°. The correlation coefficient R 2 of MODIS estimates and rain gauge data is 0.32 at a spatial scale of 2°, which coincides with other researches' result. Physically, AMSR-E passive microwave estimates overland rainfall according to the scattering effect of ice particle in the column of air and thus it is a more direct method of rainfall estimation. The validation of MODIS method indicates that clouds with a big rain intensity observed by AMSR-E often have a high R 0.65μmand low T B11μm. In other words, clouds with a high R0.65μm and low T B11μm often comprise a lot of ice particle in the air. Aqua satellite first simultaneously supplies passive microwave and infrared/visible radiative information of rain, which exposes a promising direction for rainfall research.
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