卫星月光遥感夜间气溶胶光学厚度

气溶胶可以通过气溶胶-云-辐射相互作用影响气候，但存在很大的不确定性，因此加强对气溶胶特性的观测研究具有重要科学意义和应用价值。现阶段气溶胶被动遥感主要基于白天太阳直接或散射辐射的观测，无法给出昼夜连续的气溶胶测量。除星载激光雷达外，现阶段国际上还没有成熟且空间覆盖广的夜间气溶胶观测手段，这严重制约了大气边界层、气溶胶化学和动力学的研究。2011年的可见光/红外成像仪/辐射计套件（VIIRS）包含一个昼/夜波段（DNB），该波段可以探测经过地球-大气相互作用的月光辐射以及自然或人为的夜间辐射源。基于此，本项目围绕“如何建立一套基于月光信号的夜间气溶胶光学厚度（AOD）反演算法并给出大范围的夜间AOD时空变化特征”这一科学问题，提出三个研究内容：（1）月光遥感夜间AOD算法的适用地区以及时间段；（2）算法的建立以及敏感性分析；（3）给出污染严重的华北地区夜间AOD时空变化。

Aerosol can affect climate through aerosol-cloud-radiation interaction, while there also exist great uncertainties. Therefore, it is of great scientific significance and application value to strengthen the observation and research of aerosol characteristics. At present, passive remote sensing of aerosols is mainly based on the observation of direct or scattered solar radiation in daytime, which cannot provide continuous measurement of aerosols. This seriously restricts the study of atmospheric boundary layer, aerosol chemistry and dynamics. In addition to spaceborne Lidar, currently there is no mature aerosol observation method with wide spatial coverage in the world. The Visible/Infrared Imager/Radiometer Suite (VIIRS), launched in 2011, includes a Day/Night Band (DNB). This band can detect moonlight through earth atmosphere interaction as well as natural or artificial nighttime emissions. Based on this, this project focuses on the scientific problem of “how to establish a retrieval algorithm of nighttime aerosol optical depth (AOD) by moonlight and analyze the spatiotemporal variations of nighttime AOD” and puts forward three research contents: (1) the applicable area and time period of nighttime AOD algorithm by moonlight; (2) the establishment and sensitivity analysis of the algorithm; (3) the spatiotemporal variations of nighttime AOD in North China with heavy pollution.