CO_2反演中卫星数据的云污染处理方法研究

Cloud Contaminated Satellite Data Processing Method in CO_2 Retrieving

在O2-A波段进行了温室气体卫星数据的云污染问题研究,并从光程的角度分析了散射对CO2反演的影响,提出了一种解决CO2反演中云污染问题的方法。对GOSAT L1B数据的处理结果显示晴空、有云、待定像素分别涵盖了83.58%、9.70%、6.72%的L2数据;像素的CO2反演结果中,晴空、薄卷云像素的结果与L2保持较高一致,其余像素的结果普遍低于L2结果。O2-A波段云检测有其优势但仍存在一定的局限性,如对薄卷云识别的准确性不足等,而光程法散射校正能有效改善薄卷云散射导致的CO2反演误差,可作为云检测的一个有效补充,两者结合是解决云污染问题的一种有前景的方法,同时在云检测中对薄卷云像素占多数的I类待定像素应予以更高重视。

Cloud contamination of greenhouse gas satellite data is investigated by using O2-A band, the scattering effects on CO2 retrieval from optical path-length is analyzed and a new method for solving cloud contamination problem is proposed. The results show that 83.58%, 9.70%, and 6.72% L2 data are contained in clear, cloud, and undetermined scenes. The COs retrieval of these clear scene and cirrus scene appears highly agreement with L2 product, but the other COs retrieval is generally lower than L2 product. Cloud screening in O2-A band has its own advantage but also existing insufficiency like the misidentifying of thin cirrus. Fortunately, the scattering correction method through optical path-length is an effective supplement to O2-A band cloud screening as it can improve CO2 retrieval bias due to cirrus scattering, combining them to account for cloud contamination is a promising method. Simultaneously, undetermined-I scene should be pay more attention since these undetermined scene contained abundance scene covered by cirrus.