Improved Aerosol Optical Depth and Ångstrom Exponent Retrieval Over Land From MODIS Based on the Non-Lambertian Forward Model
Improved Aerosol Optical Depth and Ångstrom Exponent Retrieval Over Land From MODIS Based on the Non-Lambertian Forward Model
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DOI：
10.1109/lgrs.2014.2303317
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发表时间：
2014-02
影响因子：
4.8
通讯作者：
Leiku Yang;Yong Xue;J. Guang;H. Kazemian;Jiahua Zhang;Chi Li
中科院分区：
文献类型：
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作者：
Leiku Yang;Yong Xue;J. Guang;H. Kazemian;Jiahua Zhang;Chi Li
在这封信中，提出了一种改进的气溶胶反演算法，通过在中分辨率成像光谱仪（MODIS）暗目标（DT）算法中采用非朗伯正演模型（正演模型）（NL_FM）来减少使用朗伯FM（L_FM）时引起的不确定性。该算法已应用于2008年全年MODIS对中国东部地区的测量。通过将结果与AERONET的结果进行比较，我们发现气溶胶光学深度（AOD）反演的准确性得到了提高，回归图集中在1：1线周围，三分之二落在预期误差（EE）包络线EE = ±0.05±0.1τ内（在0.55μm波段从L_FM的53.6％到NL_FM的68.7％）。令人惊讶的是，更准确的 AOD 检索显着改善了与粒径参数相关的埃指数 (AE) 检索。回归图往往集中在 1:1 线附近，更多的回归图落在 EE = ±0.4 范围内，从 L_FM 的 53.6% 到 NL_FM 的 80.9%。这些结果表明，与当前 MODIS 业务反演中使用的 L_FM 相比，在 MODIS DT 算法中包含 NL_FM 有可能显着改善 AERONET 的 AOD 和 AE 反演。
In this letter, an improved algorithm for aerosol retrieval is presented by employing the non-Lambertian forward model (forward model) (NL_FM) in the Moderate Resolution Imaging Spectroradiometer (MODIS) dark target (DT) algorithm to reduce the uncertainties induced when using the Lambertian FM (L_FM). This new algorithm was applied to MODIS measurements of the whole year of 2008 over Eastern China. By comparing the results with that of AERONET, we found that the accuracy of the aerosol optical depth (AOD) retrieval was improved with the regression plots concentrating around the 1 : 1 line and two-thirds falling within the expected error (EE) envelope EE = ±0.05±0.1τ (from 53.6% with L_FM to 68.7% with NL_FM at band 0.55 μm). Surprisingly, more accurate retrieval of the AOD demonstrated significantly improved the Ångstrom exponent (AE) retrieval, which is related to particle size parameters. The regression plots tended to concentrate around the 1 : 1 line, and many more fell within the EE = ±0.4 from 53.6% with L_FM to 80.9% with NL_FM. These results demonstrate that including the NL_FM in the MODIS DT algorithm has the potential to significantly improve both AOD and AE retrievals with respect to AERONET in comparison to the L_FM used in the current MODIS operational retrievals.