Intercomparison of the TAMU Vector Radiative Transfer Model (TAMU-VRTM), Community Radiative Transfer Model (CRTM), and Radiative Transfer for TOVS (RTTOV)

Accurate and fast radiation transfer models are essential in satellite remote sensing and data assimilation. Different radiative transfer models may use different absorption schemes, single-scattering property databases, or radiation transfer solvers. To evaluate their performances and seek potential improvement in the future, we make inter-comparisons of different radiative transfer models using a variety of input fields.

We further improve the TAMU Vector Radiation Transfer Model (TAMU-VRTM). It can simulate the Stokes vector of radiance at various atmospheric levels and the top of the atmosphere in both hyperspectral and narrow sensor bands. The Community Radiative Transfer Model (CRTM) was developed by the US Joint Center for Satellite Data Assimilation (JCSDA). The Radiative Transfer for TOVS (RTTOV) was originally developed by ECMWF and recently by EUMETSAT NWP Satellite Application Facility (SAF). In this study, we conduct the inter-comparison of these three models in Moderate Resolution Imaging Spectroradiometer (MODIS) and Visible/Infrared Imaging/Radiometer Suite (VIIRS) bands. We use the results based on the line by line radiative transfer model (LBLRTM) combined with the discrete ordinate radiative transfer (DISORT) model as benchmarks for the comparison. The bands radiances are simulated by these models in clear sky condition as well as under ice cloudy condition. We also compare the computational efficiencies.