Accession Number : ADA135556

Title :   Cloud Forecast Fields Comparison Test.

Descriptive Note : Technical note Aug-Sep 79,


Personal Author(s) : Mitchell,K E

PDF Url : ADA135556

Report Date : May 1982

Pagination or Media Count : 68

Abstract : This technical note reports a study of the comparative cloud forecast skill of several numerical analysis/forecast systems at the Air Force Global Weather Central (AFGWC) and the National Meteorological Center (NMC). The study compared gridded cloud forecasts derived from AFGWC's trajectory cloud forecast model (5LAYER) and NMC's 7-Layer moist primitive equation model (7LHFM) during the period August to September 1979. The study also measured the sensitivity of the 5LAYER model to the accuracy of input forecast winds (used to compute trajectories). The results show that 5LAYER and 7LHFM-derived cloud forecasts differ appreciably owing to fundamental differences in the methods used by the two centers to initialize their respective model moisture fields. During the first 24-hour forecast period, 5LAYER consistently produces more accurate cloud forecasts than the 7LHFM, because satellite and surface cloud observations are used systematically and globally in the derivation of 5LAYER initial moisture fields.

Descriptors :   *Atmosphere models, *Weather forecasting, *Clouds, *Cloud physics, Models, Equations, Forecasting, Grids, Mathematical models, Meteorology, Moisture, Numerical analysis, Observation, Trajectories, Wind, Meteorological data, Meteorological satellites, Cloud cover, Global, Algorithms, Automation, Sensitivity, Comparison, Accuracy

Subject Categories : Atmospheric Physics
      Theoretical Mathematics

Distribution Statement : APPROVED FOR PUBLIC RELEASE