Quantifying the Direct Radiative Effect of Absorbing Aerosols for Numerical Weather Prediction: A case study

We conceptualize aerosol radiative transfer processes arising from the hypothetical coupling of a global aerosol transport model and global numerical weather prediction model by applying the U.S. Naval Research Laboratory Navy Aerosol Analysis and Prediction System (NAAPS) and the Navy Global Environmental Model (NAVGEM) meteorological and surface reflectance fields. A unique experimental design during the 2013 NASA Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) field mission, allows for collocated airborne sampling by the Langley’s High Spectral Resolution Lidar (HSRL), the Airborne Multi-angle Spectro Polarimetric Imager (AirMSPI), up/down SW and broadband IR radiometers, as well as NASA A-Train support from the Moderate Resolution Imaging Spectroradiometer (MODIS), to attempt direct aerosol forcing closure. The results demonstrate the sensitivity of modeled fields to aerosol radiative fluxes and heating rates, specifically in the SW forcing and heating rates, as induced in this event from transported smoke and regional urban aerosols. Limitations are identified with respect to aerosol attribution, vertical distribution and choice of optical and surface polarimetry properties, which are discussed within the context of their influence on Numerical Weather Prediction output that is particularly important as the community propels forward towards inline aerosol modelling within global forecast systems.