北黄海圆岛海域MODIS气溶胶光学厚度产品有效性验证

利用北黄海圆岛岛基太阳光度计气溶胶光学厚度（aerosol optical depth，AOD）实测数据，在优选时空匹配窗口的基础上，对最新版本MODIS C061 AOD产品开展了有效性验证。结果表明，相对于其他尺度的采样窗口，采用30 km×30 km空间采样窗口、±0.5 h时间采样窗口可以得到更加准确的验证结果。在此时空窗口下，MODISA AOD产品（550 nm）与岛基观测数据具有非常好的一致性，相关系数达到0.98，春季、秋季和冬季AOD产品精度满足NASA的设计要求，夏季数据存在较大误差，符合NASA期望误差（[（0.04+0.1*AOD），（-0.02-0.1*AOD）]）的比例仅为40%，气溶胶模型假定不合理是其可能的误差来源。

Validation of MODIS aerosol optical depth over Yuandao in the North Yellow Sea

The latest version MODIS C061 aerosol retrievals were evaluated with collocated aerosol optical depth(AOD) from island-based Sun photometer over Yuandao in the North Yellow Sea.Based on the two kinds of data, the size of spatial-temporal windows were discussed and spatial window of 30 km×30 km and temporal window of ±0.5 h were selected.The validation results showed there was a good relationship between the MODIS AOD and the island-based AOD, the correlation coefficient was 0.98.The MODIS AOD products at 550 nm fell well within NASA expected error envelop (EE) ([(0.04+0.1*AOD), (-0.02-0.1*AOD)])in spring, autumn and winter, while the proportion within expected EE was only 40% in summer, the inconsistency between aerosol module assumption and in-situ may explain the lower precision of AOD in summer.