Global capability for AFWA's Diagnostic Cloud Forecast system

Author: John M. Henderson, Thomas Nehrkorn, C. Carlson and J. B. Eylander
January 14, 2009
16th Conference on Satellite Meteorology and Oceanography

Henderson, J. M., T. Nehrkorn, J. B. Eylander, and C. Carlson, 2009: Global capability for AFWA's Diagnostic Cloud Forecast system. Preprints, 16th Conf. on Sat. Meteor. and Oceanogr., Phoenix, AZ, Amer. Meteor. Soc., JP6.16.

The Diagnostic Cloud Forecast (DCF) model is a statistics-based cloud forecast application that is run operationally at the Air Force Weather Agency (AFWA) to support the requirements of the Air Force in theaters world-wide. The DCF builds statistical relationships between the global, satellite-based cloud analysis produced operationally by the AFWA Cloud Depiction and Forecast System II (CDFS-II), and corresponding numerical weather prediction (NWP) forecast parameters using a multiple discriminant analysis method. These relationships are then applied to current NWP forecasts to correct for NWP biases and generate cloud forecast products required by the end-users. Until recently the operational implementation of DCF at AFWA only ingested output from regional NWP models such as the Penn State/National Center for Atmospheric Research (NCAR) Mesoscale Model Version 5 (MM5) or NCAR's Weather Research and Forecasting Model (WRF-ARW). DCF has now been expanded to process the National Centers for Environmental Prediction (NCEP) operational Global Forecast System (GFS) forecasts at 0.5-degree resolution in order to provide global coverage. To accommodate the large variability in the nature of clouds between tropical and polar regions, an option was added to compute multiple statistical relationships on sub-regions within the global GFS-model window. This improves the quality of cloud products produced by the original statistical technique. Use of 0.5-degree GFS data within the DCF model is programmed to become operational in late 2008. Future upgrades to DCF will combine higher resolution NWP data, such as NCEP's operational mesoscale North American Model (NAM), with an enhanced high-resolution satellite analysis that includes cloud optical property information in addition to the current cloud top/base and type. The poster will present initial verification statistics for the global DCF system, as well as examples of future upgrades.