Estimation and validation of direct aerosol radiative forcing in the Korean peninsula using the GEMS dataset

In this study, we conducted the estimation of shortwave aerosol radiative forcing using the aerosol optical depth (AOD) and supplementary information from the Geostationary Environment Monitoring Spectrometer (GEMS) dataset. We used the libRadtran package for the radiative transfer modeling (RTM), and used the radiative forcing values provided from the Aerosol Robotic Network (AERONET) system for the input value of RTM and the validation task. Total 6 sites in the Korean peninsula are target regions, such as Seoul (Yonsei University and Seoul National university), Anmyeon, Gwangju, Gangneung, and Ulsan. In detail, we used the climatological mean of surface albedo and asymmetry parameter at 4 shortwave channels (440, 675, 870, and 1020 nm), and used daily representative single scattering albedo provided from the GEMS dataset in order to consider the different aerosol type (dust, non-absorbing, and black carbon types). These set-up conditions were finally decided after a number of sensitivity tests. As a result, our estimation of direct aerosol radiative forcing (DARF) at the surface and top of the atmosphere (TOA) shows high correlations with the DARF from the AERONET (correlation coefficient is 0.65 to 0.85 in all 6 sites). Our estimated DARF is a little underestimated compared to the DARF of AERONET, and it seems natural due to the spatial resolution difference. With this high performance, we can provide the daytime hourly variation of DARF over the whole Korean peninsula, which can be useful information to a number of application in the future.