Validation of MODIS derived aerosol optical depth over the Yangtze River Delta in China
Validation of MODIS derived aerosol optical depth over the Yangtze River Delta in China
复制标题
MODIS 得出的中国长三角地区气溶胶光学深度的验证
DOI：
10.1016/j.rse.2010.02.015
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发表时间：
2010-08-16
影响因子：
13.5
通讯作者：
Wu, Yongli
中科院分区：
文献类型：
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作者：
He, Qianshan;Li, Chengcai;Wu, Yongli
2007年7 - 10月，利用中国长江三角洲地区7个测站的MODIS气溶胶光学厚度（AODs）资料，将其与CE 318太阳光度计的550 nm波段AODs资料进行了对比分析。评价结果表明，在植被密集区，MODIS AODs（Collection 5，C 005）与CE 318的AODs具有较好的一致性，但在下垫面复杂的地区（如湖泊水体和城市地表），两者差异较大。在排除验证方案引起的显著误差的情况后，讨论了这些差异的原因。最后的验证结果表明，MODIS AODs与CE 318的相关系数为0.85，RMS为0.15，两者吻合较好。90%的MODIS个例落在Delta tau = +/-0.05+/-0.20 tau的范围内，说明MODIS气溶胶反演算法、气溶胶模型和地表反射率估算对长江三峡库区气溶胶反演总体上是合理的。然而，MODIS的气溶胶光学厚度存在系统误差，拟合直线为y=0.75x+0.13，表明在气溶胶浓度较高时，对气溶胶光学厚度的估计偏低。气溶胶模型和地表反射率估计是影响MODIS气溶胶反演误差的主要因素。(C)2010年爱思唯尔公司All rights reserved.
MODIS derived aerosol optical depths (AODs) at 550 nm are compared with sunphotometer CE318 measurements at 7 sites located at Yangtze River Delta (YRD) in China from July to October, 2007. The evaluation result indicates that MODIS AODs (Collection 5, C005) are in good agreement with those from CE318 in dense vegetation regions, but show more differences in those regions with complex underlying surface (such as at lake water and urban surface sites). Reasons for these differences are discussed after removing cases with significant errors caused by validation scheme. The final validation result shows that MODIS AODs are in good agreement with CE318 with a correlation coefficient of 0.85 and RMS of 0.15. 90% of MODIS cases fall in the range of Delta tau = +/-0.05+/-0.20 tau, indicating MODIS aerosol retrieval algorithm, aerosol models and surface reflectance estimate are generally suitably reasonable for aerosol retrieval in YRD. However, MODIS AODs show a systemic errors with fitted line of y=0.75x+0.13, indicating underestimation of AOD when aerosol loadings are high. Aerosol models and surface reflectance estimations are dominant sources of MODIS aerosol retrieval errors. (C) 2010 Elsevier Inc. All rights reserved.