The impact of different aerosol properties and types on direct aerosol radiative forcing and efficiency using AERONET version 3

Abstract

In this study, the results from a classification method are used to determine how aerosol type influence the radiative balance of the Earth's climate. Quality-assured data from the AErosol RObotic NETwork (AERONET) Level 2.0 (L2) Version 3 (V3) inversion product are used during the 2008–2017 period. The study includes the Arabian Peninsula (AP), Atlantic (AT), Middle East North Africa (MENA), South Europe (SE) and Central and East Europe (CEE). The impacts of Solar Zenith Angle (SZA), Surface Albedo (SA), Aerosol Optical Depth (AOD) and Single Scattering Albedo (SSA) on Direct Aerosol Radiative Forcing (DARF) and Efficiency (DARFeff) at the bottom and top of atmosphere (BOA, TOA) are investigated. Fine slightly absorbing particles show the highest positive gradient of DARFeffBOA with SA and the highest negative gradient of DARFefTOA with SZA. The mixed absorbing particles provide the highest alteration for DARF at the BOA with the increase of AOD. The analysis of aerosols absorptivity is performed by dividing SSA into six-subgroups. Coarse absorbing particles provide the highest (in magnitude) DARFeff values at the TOA under absorbing aerosol conditions (SSA < 0.89), whereas similar behavior is revealed by the fine absorbing particles for DARFeff values at the BOA. Furthermore, we analyze the long-term averages of RF metrics for all aerosol types among the regions of our study. At the TOA, fine non-absorbing particles show the highest absolute values for DARFeff (from −75 W m−2 to −79 W m−2) and DARF (from −38 W m−2 to −48 W m−2). At the BOA, coarse and mixed absorbing clusters indicate the highest absolute values for DARF (from −66 W m−2 to −79 W m−2) and DARFeff (from −135 W m−2 to −149 W m−2), respectively. The presented results could be used for the validation and improvement of the performance of remote sensing algorithms and models that assess the aerosol effect in radiative balance.