Two decades of aerosol observations by AATSR, MISR, MODIS and MERRA-2 over India and Indian Ocean

Atmospheric aerosols play key roles in radiation budget, ecosystem dynamics, air quality and cloud microphysics of a region thus, they greatly influence the global climate, public health. We present temporal variability atmospheric over India north Indian Ocean (NIO) for past two decades (2000–2019). Here, measurements from Moderate Resolution Imaging Spectroradiometer (MODIS) on Terra, Multi-angle (MISR) Advanced Along Track Scanning Radiometer (AATSR) Envisat, Modern-Era Retrospective analysis Research Applications version 2 (MERRA-2) reanalysis data are considered. On average, Indo Gangetic Plain (IGP) shows largest (0.5–1.2), NIO Himalaya show smallest (0.1 or smaller) Aerosol Optical depth (AOD) values. The peak AOD loading is observed June–July-August, IGP has secondary March owing to stubble biomass burning winter months. In contrast, aerosol northeast due forest during period there. inter-annual very small NIO, Bay Bengal. trends estimated combined (AATSR, MISR, MODIS MERRA-2) highest positive at lower east central regions, about 0.8–1.2/dec, statistically significant. This consistent with urban activity, industries dense population However, Desert, northern Arabian Sea insignificant negative trends, ?0.2 ?0.4/dec, as anthropogenic sources limited bias estimate that most satellite good agreement all regions (within 0.1–0.2). Even though considered, still large enough be analyses, therefore, caution increasing their plausible climate feedback these regions. assessment also demonstrate potential synergetic use multiple-platform system studies. • Thorough multiple satellites. Lower Indo-Gangetic super-hotspot accumulation. A slow steady increase 0.8–1.2/dec IGP. Desert South Central ?0.15/dec. All instruments 0.1–0.2 AOD, but slightly higher