Accession Number : ADA303897

Title :   Coherent Structures, Fluxes and Sampling Problems Over Heterogeneous Surfaces.

Descriptive Note : Final rept. 15 Dec 92-31 Dec 95,

Corporate Author : OREGON STATE UNIV CORVALLIS COLL OF OCEANIC AND ATMOSPHERIC SCIENCES

Personal Author(s) : Mahrt, Larry

PDF Url : ADA303897

Report Date : 01 JAN 1996

Pagination or Media Count : 8

Abstract : Observations of boundary-layer flow over heterogeneous surfaces collected from five recent field programs are analyzed. The spatial variation of turbulent fluxes responding to surface heterogeneity are documented for a variety of situations and provides the first study of such variations with adequately sampled surface fluxes. The data analysis also provides the first detailed examination of local circulations and mesoscale fluxes driven by spatial variations of soil moisture and transpiration. The results of these studies are being used to validate models by groups at Colorado State University, Iowa State University and Rutgers. Based on the above observational analyses, the usual bulk aerodynamic formula is modified to include the effect of generation of turbulent fluxes by, unresolved, subgrid mesoscale fluxes. In addition, the transfer coefficients for the grid-averaged fluxes are shown to be generally independent of grid size, except for cases of weak large scale flow over strong surface heterogeneity. (AN)

Descriptors :   *TURBULENCE, *ATMOSPHERIC MOTION, *BOUNDARY LAYER FLOW, HEAT TRANSFER, MATHEMATICAL MODELS, SPATIAL DISTRIBUTION, AIR FLOW, ATMOSPHERIC TEMPERATURE, TURBULENT FLOW, EDDIES(FLUID MECHANICS), METEOROLOGICAL DATA, VARIATIONS, TEMPERATURE GRADIENTS, TRANSPIRATION, HETEROGENEITY, EARTH SURFACE, MOISTURE, AIR WATER INTERACTIONS, HEAT FLUX, RADIOMETRY, ATMOSPHERE MODELS.

Subject Categories : Meteorology

Distribution Statement : APPROVED FOR PUBLIC RELEASE