两种氧气A吸收带云顶高度反演算法的理论比较与实测结果验证

近年来,氧气A吸收带作为云高反演通道重新引起学者们的关注,其中用于欧空局ENVISat/SCIAMACHY仪器的SACURA和FRESCO+两种云高算法是目前比较成熟的氧气A带云高反演算法,并已有相关产品发布。为充分了解SACURA和FRESCO+两种算法的适用性及反演效果,对两种算法特点及其模拟反演的结果进行了深入比较,在敏感性分析的基础上评估这两种算法的特点及产品精度。结果表明,FRESCO+算法对地表反照率、云量等参数的依赖性较低,得到的云高结果偏低达20～750 m,而SACURA算法对太阳天顶角、云光学厚度、地表反照率和云量等参数较敏感,得到的云高值波动性较大。不包括光学厚度小于5的云且满云时,平均云顶误差小于300 m。在亮地表上的薄云结果最差,误差最大可达10 km以上。为验证上述结论,我们对2008年度覆盖我国及周边地区两种算法的相应产品进行了统计分析,并与寿县ARM计划的地基雷达和探空资料进行了对比,表明模拟反演得到的结论可信。
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Two Kinds of Cloud Top Height Retrieval Methods with Oxygen A-Band Comparison by Simulated Data and Verification with Experimental Results in China

Retrieval of cloud top height with oxygen A-band has been proposed for decades.However,with the development of space-based instrument,more attentions are being paid to this field again.Among various retrieval methods,SACURA and FRESCO+ are successful and mature.The ESA had already developed the cloud top height products retrieval by them.In order to evaluate the precision as well as applicability of these products and develop new generation oxygen A-band retrieval method in the future,sensitivity analysis i...