Multiyear Estimates of Aerosol Direct Radiative Forcing from the MERRA-2 Reanalysis

The National Aeronautical and Space Administration Goddard Earth Science Data Information and Services Center (GES DISC) provides an aerosol reanalysis starting from year 1980 for the Second Modern-Era Retrospective analysis for Research and Applications (MERRA-2). Reanalysed products are used here to estimate the clear-sky aerosol direct radiative forcing for the Amazon Region over the period 2000-2015, using two methods previously applied in other papers. Both methods agree that the years 2005, 2007 and 2010 show the bigger significance to estimates in this region. During dry season, in a location of amazon region, the radiative direct forcing at the top of atmosphere, average to all period, varied from -2.5 to -10 W/m² and at the surface from -10 to -36 W/m², with difference associated with absorption of sunlight by aerosol layer. Already in amazon region, the estimated varied from -1.5 to -7.5 W/m² at top of atmosphere and -6.5 to -21 W/m² at the surface. The spatial distribution of forcings over the Amazon showed that they affect a large area. This values show how much the aerosols can affect the energy balance, and consequently the regional circulation and the water budget in the Amazon Region. This was the first study of a long time series of clear-sky aerosol radiative forcing on the surface, atmosphere and top of the atmosphere in the Amazon.