MODIS uydu verilerinden elde edilen aerosol optik derinliğinin Türkiye'de zamansal ve mekansal değişimi

The most recent release of Moderate Resolution Imaging Spectroradiometer (MODIS) Collection 6.1 (C6.1) aerosol optical depth (AOD) products were available with various improvements made to both the radiometric calibration and Dark Target (DT) and Deep Blue (DB) algorithms. However, the performances of the recent MODIS aerosol products have not been investigated over Turkey. This study provides an evaluation of C6.1 Terra and Aqua MODIS aerosol products with reference to the ground based AOD measurements by the Aerosol Robotic Network (AERONET) Version 3 Level 2.0 data at 10 sites in the period of 2002–2019. Considering that sparse AERONET sites are available in Turkey, 8 sites from neighboring countries were also used. The AOD retrievals were validated over different surface types defined by monthly NDVI (Normalized Difference Vegetation Index) values. Analysis was performed with direct comparisons between MODIS retrievals and AERONET measurements at regional to site scales. Meanwhile, the spatial and temporal variations were also discussed. The retrieval errors illustrated that the performance of datasets changed with surface types. Overall, the DB AOD products showed the best performance in partially vegetated urban areas. DT products matched more closely with the AERONET AODs than DB products over moderately or densely vegetated areas. DT and DB tended to overestimate and underestimate AOD, respectively. There were small differences between Terra and Aqua aerosol products. In general, Aqua AOD products were more reliable in describing the AOD over the region and recommended for selection in related aerosol studies at regional scale.