FY-3A中分辨率光谱成像仪(MERSI)红外通道采取40探元跨轨并行扫描方式，针对其辐射定标要比传统单元探测器的辐射定标复杂的问题，研究了MERSI红外通道的多探元辐射定标方法。首先，基于星上黑体观测进行逐探元的辐射定标处理，消除探元辐射响应差异条纹；然后，利用各探元与基准探元光谱响应对不同温度黑体光谱辐亮度建立比值关系，基于其随着辐亮度呈非线性变化的关系，对逐探元定标后图像进行探元光谱差异的辐亮度归一化补偿，从辐射机理上最大限度地消除图像条纹，实现了多探元观测目标辐射信号的光谱响应差异归一化。为了验证MERSI红外通道辐射定标精度，文中还利用同时过星下点观测(SNO)交叉定标方法，将MERSI定标结果与美国Terra中分辨率成像光谱仪(MODIS)定标结果进行比对，结果显示，相对于后者,MERSI的红外通道亮温高1 K左右，认为这可能与两者的通道带宽不同有关。

As the FY-3A Medium Resolution Spectral Imager(MERSI) takes a cross-track scanning by 40 detectors in a thermal Infrared Window band,its radiometric calibration is more complicate than those of traditional single detectors. Therefore,this paper investigates a multi-detector radiometric calibration method for the MERSI. Firstly, the operational calibration algorithm for the IR band of MERSI based on onboard blackbody detector-by-detector is proposed to eliminate the radiometric response difference strips.Then,based on the radiance ratios of each detector to reference detector at different blackbody temperatures, this algorithm conducts the normalization processing for SRF-different bias (spectral normalization)to alleviate the image strips by radiometric mechanism. To verify the accuracy of MERSI calibration,the inter-calibration between MERSI and Moderate-resolution Imaging Spectroradiometer(MODIS) is performed by using Simultaneous Nadir Observation (SNO).Experiments show that the difference of their brightness temperatures is about 1.0 K,which may come from their different bandwidths.