AU - Bayat, Ali AU - Assar Enayati, Ahmad AU - Toshani, Azimeh TI - Verification of CALIOP, MODIS, MISR, and OMI aerosol optical depth retrievals against Sun-photometer data over Zanjan PT - JOURNAL ARTICLE TA - jgs JN - jgs VO - 21 VI - 62 IP - 62 4099 - http://jgs.khu.ac.ir/article-1-3297-en.html 4100 - http://jgs.khu.ac.ir/article-1-3297-en.pdf SO - jgs 62 ABĀ  - In this paper, aerosol optical depth measured by Caliop, MODIS, MISR, and OMI satellite sensors is compared with Sun-photometer data located in the Institute for Advanced Studies in Basic Sciences (IASBS) from December 2009 to December 2013 over Zanjan city. We computed figures for root mean square error (RMSE), mean absolute error (MAE) and root mean bias (RMB) between space-born and ground-based sensor measurements. The results show that the Caliop and MISR sensors have the highest correlation (0.61 and 0.54), respectively, with Sun-photometer measurements over Zanjan area. MISR, Caliop, and OMI sensors have the closest aerosol optical depth data to the Sun-photometer measurements (the fitted line slope is 0.68, 0.61 and 0.59, respectively) which represents the appropriate model used in the sensors to extract the aerosol optical depth. The variable monthly AOD figures obtained with different sensors indicate underestimation by MODIS and Caliop instruments (0.32 and 0.83 respectively) over Zanjan city relative to the Sun-photometer data, and overestimation by OMI and MISR instruments (1. 23 and 1.08 respectively). CP - IRAN IN - University of Zanjan, Faculty of science, physics group LG - eng PB - jgs PG - 201 PT - Research YR - 2021