Accession Number : ADA292864

Title :   Clouds-Their Prediction and Simulation.

Descriptive Note : Final rept. 1 Jun 91-31 Dec 94,

Corporate Author : COLORADO STATE UNIV FORT COLLINS DEPT OF ATMOSPHERIC SCIENCE

Personal Author(s) : Cotton, W. R.

PDF Url : ADA292864

Report Date : 24 FEB 1995

Pagination or Media Count : 14

Abstract : Physically-based cloud forecasting algorithms have been developed in support of the long range goal of developing a comprehensive mesoscale numerical prediction cloud forecast system. Algorithms for forecasting cirrus clouds include development of both heterogeneous and homogeneous ice nucleation schemes, a double-moment ice crystal distribution parameterization, liquid and ice saturation calculations at very cold temperatures, and of radiative properties of cirrus. The impact of these algorithms on mesoscale prediction of cirrus has been evaluated for a number of FIRE I and II cirrus data sets. One of the FIRE stratus cases was simulated to evaluate various boundary layer cloud fractional coverage schemes. The best performIng schemes have been interfaced with the RAMS radiation codes for forecasting boundary layer stratus. A convective cloud parameterization scheme designed for use in mesoscale models has been tested against data observed during the Cape over South Florida. Improvements to the cumulus parameterization scheme are now being made and tested. A new two-moment microphysics scheme has been developed, implemented and tested in RAMS. The additional degrees of freedom in this scheme allow a more realistic prediction of cloud microstructure and corresponding radar reflectivities and optical depths. (AN)

Descriptors :   *MATHEMATICAL MODELS, *CLOUD PHYSICS, *CIRRUS CLOUDS, *STRATUS CLOUDS, ALGORITHMS, COMPUTERIZED SIMULATION, LOW TEMPERATURE, MICROSTRUCTURE, FORECASTING, BOUNDARY LAYER, RADIATIVE TRANSFER, NUCLEATION, ICE FORMATION, DEGREES OF FREEDOM, MATHEMATICAL PREDICTION, HETEROGENEITY, AREA COVERAGE, HOMOGENEITY, CONVECTION(ATMOSPHERIC), CUMULUS CLOUDS.

Subject Categories : Meteorology

Distribution Statement : APPROVED FOR PUBLIC RELEASE