Validation of the Community Radiative Tansfer Model with the MODIS Collection 6 Ice Cloud Model

The Community Radiative Transfer Model (CRTM) developed by the Joint Center for Satellite Data Assimilation (JCSDA) facilitates the forward and adjoint radiative transfer simulations involved in satellite data assimilation and remote sensing implementations under all weather conditions. With the development of the new MODIS Collection 6 ice cloud model, consistent retrieval results of the ice cloud optical thickness are achieved compared with the retrievals from active sensors. Therefore, to improve the CRTM simulation capacity with ice clouds, we incorporate the MODIS collection 6 ice habit model into CRTM. In this work, CRTM under ice cloud conditions is validated in comparison with MODIS satellite observations. Representative scenes from MODIS observations are identified and used for CRTM simulations to calculate the brightness temperatures at the top of atmosphere. The inaccuracy range of CRTM with the MODIS Collection 6 ice cloud model is identified, and the implications to enhance CRTM are discussed. Furthermore, we also use the updated CRTM to simulate the radiances at the VIIS (Visible Infrared Imager Radiometer Suite) channels in comparison with VIIS observations.