极轨气象卫星红外通道太阳污染时相规律与订正模型研究

项目名称： 极轨气象卫星红外通道太阳污染时相规律与订正模型研究

项目编号： No.41471302

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 天文学、地球科学

项目作者： 胡秀清

作者单位： 国家卫星气象中心

项目金额： 87万元

中文摘要： 极轨卫星在高纬昼夜交替时太阳光会进入遥感器内部，造成定标系统和图像的严重污染。本研究针对风云极轨卫星光学载荷普遍存在的太阳污染共性问题，开展其表现特征和时空变化规律探索研究，寻找污染形成的内外部根源和季节变化机理，研究污染数据的自动甄别方法。针对太阳污染导致定标源（黑体冷空）和图像的异常特征模态，重点评估它对红外通道定标精度的影响和不确定性。模拟太阳在轨道不同位置对仪器部件照射变化，及由此形成的反射污染和黑体温度梯度，结合黑体内部热力非平衡传递模型，建立太阳污染与定标误差关联模型。开展红外通道太阳污染的订正模型与方法研究，针对污染导致的太阳反射增大、黑体温度梯度、冷空钳位污染等方面建立订正算法，采用快速傅立叶变换FFT和经验模态分解EMD等数据处理方法，实现定标过程中对污染的准确过滤和本征模态分解，建立太阳污染实时动态订正模型，为业务定标算法改进和卫星历史数据重新再定标奠定理论和技术基础。

中文关键词： 红外遥感；太阳污染；辐射定标；订正模型

英文摘要： The solar impingement into the sensors will lead to severe contaminations on calibration systems and earth scenes when the polar orbiting spacecrafts come in or out of the terminator of each orbit around high latitude. This solar contamination is common problem on space-borne optical payloads of domestic polar orbiting meteorological satellites. This study focuses on the research of apparent features and spatio-temporal variations of solar contamination, then try to find its internal and external sources of the formation and seasonal variation mechanisms. This study will establish an algorithm to discriminate the contaminated data by solar. For the abnormal mode of solar contamination on calibration targets (blackbody and cold space view) and earth scenes, we mainly assess its effect on the calibration accuracy and uncertainty of the infrared bands. A calibration error model is established by simulating the variation of the solar illumination on instruments in different orbit positions and consequent reflective contamination and blackbody temperature gradients. This model will also combine internal non-equilibrium thermal model and heat transfer of the blackbody. The correction model and method of solar contamination will be developed for the infrared bands based on the abnormal increase of the reflective radiation in mid-infrared band, blackbody temperature gradient and wrong space-view clamp. we plan to conduct the contamination correction by using these methods such as FFT transformation and EMD method to accurately filter and decompose the signals which was contaminated by solar impingement. Based on these procedures, one can establish the real-time dynamic correction model for solar contamination. This study can not only pave the theoretical and technique basis for improving the operational calibration algorithm, but also establish a better recalibration processing for satellites historical data.

英文关键词： Infrared Remote sensing;solar contamination;radiometric calibration;Correction Model