多通道自校准热红外辐射计的研制和外场应用

Development and Field Application of Multi-Channel Self-Calibrating Thermal Infrared Radiometer

为更好的满足热红外波段卫星遥感器的外场定标需求,提高外场定标的定标频次、时效性和测量精度,研制了具有自动化观测能力的多通道自校准热红外辐射计,用于测量外场大气下行辐射亮度和地表辐射亮度。介绍了多通道自校准热红外辐射计的结构设计、工作原理和实验室定标,并在此基础上开展了外场实验。以青海省格尔木定标场的观测数据为例,结合场地多通道数据中的温度与发射率分离算法,得到定标场地的真实温度和通道发射率结果,对不确定度进行了评估。数据结果表明,多通道自校准热红外辐射计四个光谱通道获取的通道发射率相对标准偏差最大为0.012,场地温度偏差在0.11 K以内,研制的多通道自校准热红外辐射计能够满足热红外波段外场定标的应用需求,为开展热红外波段遥感器的场地自动化辐射定标的研究奠定了基础。

To better meet the field radiometric calibration requirements of the thermal infrared band satellite remote sensor,and to improve the calibration frequency,timeliness,and measurement accuracy of the field radiometric calibration,a Multi-channel Self-calibration Thermal Infrared Radiometer(MSTIR)with automatic observation capabilities has been developed for measuring the atmospheric downward radiance and ground surface radiance in the field.In this paper,the structure,working principle,and test results of the MSTIR were introduced,and field experiments are carried out on this basis.Taking the observation data of the Golmud calibration field in Qinghai Province as an example,combined with the temperature and emissivity separation algorithm of the multi-channel data of the site,the land surface temperature,and channel emissivity results of the calibration site were obtained,and the uncertainty was evaluated.The data results show that the maximum relative standard deviation of channel emissivity obtained by the four spectral channels of the MSTIR is 0.012 at maximum,and the field temperature deviation is within 0.11 K.The developed MSTIR can meet the application requirements of thermal infrared band field calibration,which lays a foundation for the application of site automatic radiometric calibration of thermal infrared band remote sensor.