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为了使搭载在风云三号B星上的微波成像仪(MWRI,Microwave Radiation Imager)与搭载在GCOM-W1(Global Change Observation Mission 1st-Water)卫星上的AMSR-2(Advanced Microwave Scanning Radiometer 2)的数据可以衔接使用,并为以后FY-3B/MWRI北极地区遥感参数反演研究提供基础,本文以GCOM-W1/AMSR-2数据为对比数据,以北极海洋区域为研究区域,对两传感器对应的10个通道的升、降轨亮温数据进行交叉定标。首先,对MWRI和AMSR-2各通道逐月在研究区域进行偏差分析；其次,对MWRI和AMSR-2各通道逐月在海冰区域和开阔水域进行偏差分析；最后,对MWRI和AMSR-2各通道逐月在研究区域进行交叉定标,并对定标结果进行评价。研究结果表明：第一,MWRI各通道亮温数据小于AMSR-2,且相同频率下,垂直极化各通道逐月平均偏差的绝对值大于水平极化各通道,升、降轨数据在各通道的差异较小,逐月平均偏差的差值小于1K；第二,在海冰区域,升、降轨各通道逐月平均偏差相差小于1K,在开阔水域则介于0～1.5K之间；第三,通过进行线性回归分析,MWRI和AMSR-2各通道相关系数大于0.99,具有强相关性,并得到升、降轨各通道各月份交叉定标的斜率和截距；第四,定标后MWRI’的亮温值与AMSR-2的亮温值一致性较好,说明交叉定标的效果较好。
With the capabilities of all-weather and all-time, microwave radiometers have been widely applied in polar regions research. Microwave Radiation Imager(MWRI) on FY-3B is the microwave radiometer of Chinese own research and development which has aroused widespread concern. Long time series of earth observation data records play an important role in the research of earth environment changes and trends. In order to provide the intercalibration result and provide the basis of retrieving remote sensing parameters in Arctic region in future, the Arctic region is used as the study area and the data of Advanced Microwave Scanning Radiometer-2(AMSR-2) on GCOM-W1(Global Change Observation Mission 1st-Water) is considered as the standard data. Ascending and descending brightness temperature at 10 channels in 2015 from FY-3B/MWRI are calibrated against that from GCOM-W1/AMSR-2. Before analyzing the brightness temperature data and inter-calibrating, there are five steps for preprocessing the data. The first step is reading data that means transferring value DN of remote sensing to brightness temperature value in the research region. Secondly, if the standard deviation of values in a grid and 8 surrounding grids is more than 3K, the values in these nine grids should be eliminated. And the value, which is more than 300K or less than 10K, should also be eliminated. This is the process of data quality control. Thirdly，stereographic projection is used to project the brightness temperature value, time, longitude and latitude into 896×608 grids. Fourthly，because of the mixed pixel at the land-sea boundary and marginal ice zone(MIZ), data in these areas should be eliminated. First，the grid data of 7×7 around the land data is marked as the land, and then eliminate the data marked as land. Then, the ratio of V187 to V365 from AMSR-2 is used to calculate the MIZ. The ratio，equal to 0.92，is viewed as the threshold to divide the sea ice and the open water. Set the 3×3 grids as a template. And if the template includes the grids represented sea ice and open water, then eliminate the 9 grids. The fifth step is to set the time window as 30 minute and the space window as 12.5×12.5km and convert two-dimension matched data to one dimension data which is used to inter-calibrate. The intercalibration results of MWRI and AMSR-2 are as follows. Firstly, it is indicated that the brightness temperature data of each channel of MWRI is smaller than that of AMSR-2, and the absolute values of monthly bias of vertical polarization channels are greater than that of horizontal polarization channels at the same frequency. The difference of monthly bias between ascending and descending is small in each channel, which is less than 1K. Secondly, in the sea ice area, the difference of the monthly bias in each channel between the ascending and descending orbit is less than 1K, while in the open water it is between 0 and 1.5K. Thirdly, through linear regression analysis, most of the correlation coefficients of MWRI and AMSR-2 in each channel are above 0.99, showing a good correlation. And the slope and intercept of the intercalibration of each channel in the ascending and descending are obtained. Fourthly, the brightness temperature of MWRI after calibrating is consistent with that of AMSR-2，indicating that the intercalibration is effective.