Global dust optical depth climatology derived from CALIOP and MODIS aerosol retrievals on decadal timescales: regional and interannual variability

Abstract. We derived two observation-based global monthly mean dust aerosol optical depth (DAOD) climatological datasets from 2007 to 2019 with a 2? (latitude) × 5? (longitude) spatial resolution, one based on Cloud-Aerosol Lidar Orthogonal Polarization (CALIOP) and the other Moderate Resolution Imaging Spectroradiometer (MODIS) observations. In addition, CALIOP dataset also includes vertical extinction profiles. Dust is distinguished non-dust aerosols particle shape information (e.g., lidar depolarization ratio) for size absorption fine-mode fraction, Ångström exponent, single-scattering albedo) MODIS, respectively. The compare reasonably well results reported in previous studies collocated Aerosol Robotic Network (AERONET) coarse-mode AOD. Based these datasets, we carried out comprehensive comparative study of temporal climatology dust. On multi-year average basis, (60? S–60? N) annual DAOD 0.032 0.067 according MODIS retrievals, most dust-active regions, generally correlates (correlation coefficient R>0.6) DAOD, although value significantly smaller. 18 %, 34 54 31 % smaller than over Sahara, tropical Atlantic Ocean, Caribbean Sea, Arabian Applying regional specific ratio (LR) 58 sr instead 44 used operational retrieval reduces difference 8 Sahara 12 Ocean. However, eastern Asia northwestern Pacific Ocean (NWP), show weak correlation. Despite discrepancies, similar seasonal interannual variations DAOD. For NWP, both declining trend at rate about 2 yr?1. This decreasing consistent observed southern Gobi Desert 3 yr?1 5 turn found be correlated increasing vegetation surface wind speed area.