Lin, Hui-Chuan, and Zhiquan Liu, National Center for
Atmospheric Research
Assimilation
of the Moderate Resolution Imaging Spectroradiometer (MODIS) radiances has been
developed within the National Centers for Environmental Prediction
(NCEP)Gridpoint Statistical Interpolation (GSI) three-dimensional variational
(3DVAR)data assimilation system using the Community Radiative Transfer Model
(CRTM) as the radiative transfer model. The visible land surface reflectance in
CRTM is derived from a look-up table with respect to the surface type and
wavelength under the assumption of a Lambertian surface. The MODIS
Bidirectional Reflectance Distribution Function (BRDF) product, MCD43, was used
to better estimate the land surface reflectance for MODIS bands 1 through 7 to
improve the CRTM forward radiance calculations. Weather Research and Forecasting/Chemistry
(WRF/Chem) model with the Goddard Chemistry Aerosol Radiation and Transport
(GOCART) module was used to provide the initial aerosol concentrations. The
assimilation of MODIS aerosol-sensitive
x radiances was tested over a domain encompassing the continental United
States. The impact on aerosol
analyses and subsequent forecasts was compared to that of assimilating retrived
total aerosol optical depth. The results will be presented.