沙尘气溶胶卫星遥感现状与需要关注的若干问题

沙尘暴是全球干旱、半干旱地区特有的一种灾害性天气,所产生的沙尘气溶胶是全球气溶胶系统重要组成部分,对全球环境、天气、气候和生态有复杂的影响。沙尘气溶胶作为一种吸收性气溶胶,对太阳辐射有着较强的吸收,还能通过加热大气、改变大气稳定度、蒸发云滴、减少云量等"半直接方式"影响气候。卫星遥感对沙尘气溶胶的监测具有独特的优势,是全球沙尘研究的重要手段。本文系统整理和介绍了目前常用的可见近红外、热红外、被动微波、紫外和主动激光测量等五类卫星遥感沙尘气溶胶的主要方法,在总结典型遥感仪器和主要产品基础上,讨论了遥感产品的定量精度和地面验证问题,结合辐射传输理论模拟了可见近红外和热红外的卫星观测,探讨了可见近红外遥感的地表反照率影响和热红外高光谱遥感的波段选择问题,最后对未来的一些研究重点进行了展望。

Current Status of Satellite Based Dust Aerosol Remote Sensing and Some Issues to Be Concerned

Dust storm is a typical weather disaster which outbreaks in arid and semi-arid areas globally. The dust aerosol generated from dust storm dominates the aerosol loading in the troposphere and has comprehensive impacts on the global environment, weather, climate and ecology. As a kind of absorbing aerosol, dust aerosol has strong absorption on the incoming solar radiation. Dust aerosol can affect the climate through the semi-direct effect, such as heating the atmosphere, changing the atmospheric stability, evaporating the cloud droplet and reducing the cloud amount. Satellite remote sensing has showed special priority on dust monitoring and has become an indispensable way for dust aerosol study. The main satellite-based dust aerosol remote sensing methods are summarized in this paper as the visible-infrared method, thermal infrared method, microwave method, ultraviolet method and active lidar-based method. In addition, typical instruments and products are introduced, and the accuracy of products and the validation by ground-based remote sensing network are discussed. Based on the radiation transfer theory, the visible-infrared and thermal infrared radiance observed by satellite are simulated. Moreover, the effect of surface albedo and the channel selection issue are discussed for the visible remote sensing and thermal infrared hyperspectral remote sensing separately. Finally, some prospects in the future study for the satellite-based dust aerosol remote sensing are presented.