Interdecadal Changes in Aerosol Optical Depth over Pakistan Based on the MERRA-2 Reanalysis Data during 1980–2018

The spatiotemporal evolution and trends in aerosol optical depth (AOD) over environmentally distinct regions Pakistan are investigated for the period 1980–2018. AOD data this was obtained from Modern-era retrospective analysis research applications, version 2 (MERRA-2) reanalysis atmospheric products, together with Moderate-resolution imaging spectroradiometer (MODIS) retrievals. climatology of AODMERRA-2 is analyzed three different contexts: entire study domain (Pakistan), six within domain, 12 cities chosen domain. time-series MODIS MERRA-2 shows similar patterns individual cities. its seasonality vary strongly across Pakistan, lowest (0.05 ± 0.04) highest (0.40 0.06) autumn summer seasons desert coastal regions, respectively. During period, annual trend increased between 0.002 0.012 year−1. increase attributed to an population emissions natural and/or anthropogenic sources. A general central lower Indus Basin ascribed large contribution dust particles desert. winter spring, a significant decrease observed northern Pakistan. (2002–2018) were compared, results show visible differences datasets due theuseof versions collection methods. Overall, present provides insight into regional pronounced seasonal behavior