Identification of aerosol types over the central Indo-Gangetic Plain using multi-satellite observations

Identification and quantification of aerosol types in the central Indo-Gangetic Plain (IGP) region is done using long-term (2005 - 2019) and simultaneous datasets, from satellite and reanalysis, of aerosol optical depth (AOD), absorbing aerosol index (AAI) and Ångström exponent (α). In order to identify aerosol types in the central IGP, we used two classification methods by assigning the predefined thresholds of (i) AOD and $\alpha$ and (ii) AOD, a and AAI. Results derived from Method 1 suggest anthropogenic aerosols (AA) are dominant during the study period followed by mixed type (MT) and biomass burning (BB) aerosols over Gorakhpur. From Method 2, it is apparent that absorbing aerosols dominate during pre-monsoon (PM), post-monsoon (PoM) and winter (W) seasons, and non-absorbing aerosols during monsoon (M). BB aerosols derived from method 1 and carbonaceous aerosols from method 2 showed the highest contribution during PoM and W season. This is due to increased burning of agricultural waste and forest fires in the IGP region during this period. Dust aerosols derived from both methods showed maximum contribution during PM season, with marginal contributions during M and W seasons, respectively, and negligible during PoM season.