Validating CRAS Forecasts over Antarctica
Here is a 36-hour forecast 6.7µm water vapor image (clear sky calculation) computed from the real time Antarctic CRAS model output valid 12UTC, February 24, 2006. The validating image is a composite 6.7µm image made from multiple satellites (NOAA, DMSP, GMS,GOES). Most of the circulations present in the composite images were captured by the CRAS.
The CIMSS Regional Assimilation System (CRAS) is a regional numerical weather prediction system used to assess the impact of space-based observations on numerical forecast accuracy. Since 1995, the development of CRAS model dynamics and physics has been guided by validating forecasts against observations from the Geostationary Operational Environmental Satellite (GOES). Improvements to the CRAS include upgrades to the cloud physics, convective parameterization, turbulent mixing and radiation physics. Gradient information is preserved in the CRAS by substituting 6th-order filtering in place of horizontal diffusion. These updates have led to more accurate forecasts of clouds and precipitation.