The impact of southern African biomass burning aerosols on temperature tendencies in the GEOS-5 Earth System Model
Here, the GEOS-5 DAS analysis update (AU) -- the difference between the meteorological analysis and the model forecast -- provides an observational constraint on our simulations. The AU represents the complex combination of all model errors due to inadequate representation of physical processes (model parametrizations), numerical errors, and processes that have been omitted from the model. By examining the AU for temperature we demonstrate that there is a clear correlation between the AU and AOD over southern Africa during the biomass burning season, indicating that the effects of aerosols are contributing to the model “error” for temperature. In a series of sensitivity studies in which we vary aerosol parameters (amount, absorption), we examine the effect of aerosols on temperature tendencies and the AU. We show that, in combination with comparisons of aerosol properties to observations (e.g. from MODIS), analysis of these tendencies can be a useful metric for tuning aerosol properties to minimize the AU.