Intercomparison of satellite dust retrieval products over the west African Sahara during the Fennec campaign in June 2011
Intercomparison of satellite dust retrieval products over the west African Sahara during the Fennec campaign in June 2011
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DOI：
10.1016/j.rse.2013.05.003
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发表时间：
2013-09
影响因子：
13.5
通讯作者：
J. Banks;H. Brindley;C. Flamant;M. Garay;N. C. Hsu;O. Kalashnikova;L. Klüser;A. Sayer
中科院分区：
文献类型：
--
作者：
J. Banks;H. Brindley;C. Flamant;M. Garay;N. C. Hsu;O. Kalashnikova;L. Klüser;A. Sayer
2011年6月期间从IASI，MISR，MODIS和SEVIRI卫星仪器的撒哈拉沙漠上空的气溶胶光学厚度反演算法进行了比较，以了解每个检索方法的优点和缺点。特别注意的是气象条件的影响，陆地表面的属性，和灰尘负载的大小。研究期间对应于第一次Fennec密集测量活动的时间，该活动提供了对灰尘特性和负载的新的地面和飞机测量。验证使用地面AERONET太阳光度计数据表明，卫星产品，SEVIRI检索是最能够检索的光学厚尘事件期间的灰尘，而IASI和中分辨率成像光谱仪在低尘埃负荷表现更好。这可能会显着影响观测的沙尘排放和平均沙尘气候。MISR和MODIS对气象条件的变化最不敏感，而SEVIRI在潮湿条件下倾向于高估气溶胶光学厚度（AOD）（相对于AERONET的偏差为0.31），特别是在AOD<1的低沙尘负荷下。进一步的比较与机载激光雷达测量在芬内克运动，这提供了进一步的证据，从AERONET比较的推论。还研究了表面性质对反演结果的影响。在高海拔地区，IASI反演的AOD与AERONET观测结果最一致，而MODIS反演的AOD往往偏低。相比之下，在最小发射表面上，IASI显著低估了AOD（偏差为-0.41），而MISR和SEVIRI显示出最接近的一致性。
Four aerosol optical depth retrieval algorithms over the Sahara Desert during June 2011 from the IASI, MISR, MODIS, and SEVIRI satellite instruments are compared against each other in order to understand the strengths and weaknesses of each retrieval approach. Particular attention is paid to the effects of meteorological conditions, land surface properties, and the magnitude of the dust loading. The period of study corresponds to the time of the first Fennec intensive measurement campaign, which provides new ground-based and aircraft measurements of the dust characteristics and loading. Validation using ground-based AERONET sunphotometer data indicates that of the satellite products, the SEVIRI retrieval is most able to retrieve dust during optically thick dust events, whereas IASI and MODIS perform better at low dust loadings. This may significantly affect observations of dust emission and the mean dust climatology. MISR and MODIS are least sensitive to variations in meteorological conditions, while SEVIRI tends to overestimate the aerosol optical depth (AOD) under moist conditions (with a bias against AERONET of 0.31), especially at low dust loadings where the AOD<1. Further comparisons are made with airborne LIDAR measurements taken during the Fennec campaign, which provide further evidence for the inferences made from the AERONET comparisons. The effect of surface properties on the retrievals is also investigated. Over elevated surfaces IASI retrieves AODs which are most consistent with AERONET observations, while the AODs retrieved by MODIS tend to be biased low. In contrast, over the least emissive surfaces IASI significantly underestimates the AOD (with a bias of −0.41), while MISR and SEVIRI show closest agreement.