The Microwave Radiation Imager(MWRI),boarded on the FY-3 series satellites:FY-3B,FY-3C,and FY-3D,is the first satellite-based microwave radiometer in China,commencing passive microwave brightness temperature data acqu...The Microwave Radiation Imager(MWRI),boarded on the FY-3 series satellites:FY-3B,FY-3C,and FY-3D,is the first satellite-based microwave radiometer in China,commencing passive microwave brightness temperature data acquisition since 2010.The Advanced Microwave Scanning Radiometer 2(AMSR2) boarded on the Global Change Observation Mission 1st-Water(GCOM-W1),has been operational since 2012.Despite the FY-3 series satellites are equipped with the same MWRI and all MWRIs sharing comparable parameters and configurations as AMSR2,disparities in observation times and satellite platforms result in inconsistencies in the data obtained by different satellites,which further impacting the consistency of retrieved geophysical parameters.To improve the consistency of brightness temperatures from FY-3B,FY-3C,FY-3D/MWRI,and GCOM-W1/AMSR2,cross-calibrations were conducted among brightness temperatures at ten-channel from above four platforms.The consistency of derived snow depth from MWRIs and AMSR2 in China before and after the calibration were also analyzed.The results show that the correlation coefficients of brightness temperatures at all channels between sensors exceed0.98.After cross-calibration,the RMSEs and biases of brightness temperatures at all frequencies and snow depth in China derived from them reduce to varying degrees.The consistencies in both brightness temperatures and snow depth of FY-3B/MWRI,FY-3D/MWRI,and AMSR2 are higher than those of FY-3C and others.These findings advocate for the utilization of cross-calibrated brightness temperatures from FY-3B/MWRI,FY-3D/MWRI,and AMSR2,which share similar satellite overpass time,to derived a long-term snow depth dataset.展开更多
雪水当量是气候模型与大尺度水文模型中的一个重要参数。积雪容量对全球气候变化研究、大尺度径流估算与水资源管理等方面都有很重要的意义。因此研究积雪辐射模型模拟特征及模型验证显得极为重要。本文选用的积雪辐射模型是采用考虑多...雪水当量是气候模型与大尺度水文模型中的一个重要参数。积雪容量对全球气候变化研究、大尺度径流估算与水资源管理等方面都有很重要的意义。因此研究积雪辐射模型模拟特征及模型验证显得极为重要。本文选用的积雪辐射模型是采用考虑多次散射的双矩阵法(M atrix Doub ling Formu lation)作为求解辐射传输方程的方法,利用致密介质理论来考虑积雪的近场效应,辐射传输方程的边界条件和下垫面辐射计算则采用高级积分方程模型(AIEM)。文中首先分析了辐射模型对下垫面参数特性和积雪颗粒特性的敏感性,结果表明下垫面特性和积雪颗粒大小对当前人们采用的温度梯度雪水当量反演算法有着很大影响。另外,本文利用瑞士W e issfluhjoch试验区的地面实验数据,对该积雪辐射模型在宽波段高频率和大角度的辐射信号模拟能力做了验证,验证结果表明该模型模拟值与地面实测数据吻合很好,说明积雪辐射模型能很好模拟自然地表的积雪辐射信号。展开更多
基金supported by the National Natural Science Foun-dation of China(42125604,42171143)Innovative Development Project of China Meteorological Administration(CXFZ 2022J039).
文摘The Microwave Radiation Imager(MWRI),boarded on the FY-3 series satellites:FY-3B,FY-3C,and FY-3D,is the first satellite-based microwave radiometer in China,commencing passive microwave brightness temperature data acquisition since 2010.The Advanced Microwave Scanning Radiometer 2(AMSR2) boarded on the Global Change Observation Mission 1st-Water(GCOM-W1),has been operational since 2012.Despite the FY-3 series satellites are equipped with the same MWRI and all MWRIs sharing comparable parameters and configurations as AMSR2,disparities in observation times and satellite platforms result in inconsistencies in the data obtained by different satellites,which further impacting the consistency of retrieved geophysical parameters.To improve the consistency of brightness temperatures from FY-3B,FY-3C,FY-3D/MWRI,and GCOM-W1/AMSR2,cross-calibrations were conducted among brightness temperatures at ten-channel from above four platforms.The consistency of derived snow depth from MWRIs and AMSR2 in China before and after the calibration were also analyzed.The results show that the correlation coefficients of brightness temperatures at all channels between sensors exceed0.98.After cross-calibration,the RMSEs and biases of brightness temperatures at all frequencies and snow depth in China derived from them reduce to varying degrees.The consistencies in both brightness temperatures and snow depth of FY-3B/MWRI,FY-3D/MWRI,and AMSR2 are higher than those of FY-3C and others.These findings advocate for the utilization of cross-calibrated brightness temperatures from FY-3B/MWRI,FY-3D/MWRI,and AMSR2,which share similar satellite overpass time,to derived a long-term snow depth dataset.
文摘雪水当量是气候模型与大尺度水文模型中的一个重要参数。积雪容量对全球气候变化研究、大尺度径流估算与水资源管理等方面都有很重要的意义。因此研究积雪辐射模型模拟特征及模型验证显得极为重要。本文选用的积雪辐射模型是采用考虑多次散射的双矩阵法(M atrix Doub ling Formu lation)作为求解辐射传输方程的方法,利用致密介质理论来考虑积雪的近场效应,辐射传输方程的边界条件和下垫面辐射计算则采用高级积分方程模型(AIEM)。文中首先分析了辐射模型对下垫面参数特性和积雪颗粒特性的敏感性,结果表明下垫面特性和积雪颗粒大小对当前人们采用的温度梯度雪水当量反演算法有着很大影响。另外,本文利用瑞士W e issfluhjoch试验区的地面实验数据,对该积雪辐射模型在宽波段高频率和大角度的辐射信号模拟能力做了验证,验证结果表明该模型模拟值与地面实测数据吻合很好,说明积雪辐射模型能很好模拟自然地表的积雪辐射信号。
