摘要
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ENVI-Sat/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20～750m,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300m。在亮地表上的薄云结果最差,误差最大可达10km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。
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 is carried out herein.It is investigated that the result of FRESCO＋ is insensitive to the surface albedo,cloud amount and other parameters.The cloud top height is underestimated about 20～750 m.While the result of SACURA is more susceptible to the solar zenith angle,cloud optical depth,surface property and cloud amount.The retrieval results of cloud top height change dramatically.Except the situation that the cloud optical depth is lower than 5,the average error of SACURA is smaller than 300 m with full cloud covering.Meanwhile,the result will be the worst if the value of cloud optical depth is smaller than 5 and the earth＇s surface is bright.The maximum error is more than 10 km.To confirm the conclusions above,verification with experimental results are also carried on.We firstly analyse statistically the satellite＇s cloud top height L2 products of 2008 which covers China and neighboring regions,and then compare with MACR and BBSS＇s information supplied by the ARM mobile facility located in Shouxian.The analysis shows that the conclusions,which are obtained by the simulations,are accurate and reliable.Besides,some suggestions for improvement of the algorithm and applicability of satellite products are also put forward.
出处
《遥感技术与应用》
CSCD
北大核心
2011年第1期18-32,共15页
Remote Sensing Technology and Application
基金
国家自然科学基金资助项目(40675018和40775026)
