Coherent Structures, Fluxes and Sampling Problems Over Heterogeneous Surfaces.

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)

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1996
Accession Number
ADA303897

Entities

People

  • Larry J. Mahrt

Organizations

  • Oregon State University

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Aircrafts
  • Atmospheric Sciences
  • Boundaries
  • Boundary Layer
  • Boundary Layer Flow
  • Coefficients
  • Data Analysis
  • Demographic Cohorts
  • Flow
  • Heterogeneity
  • Layers
  • Moisture
  • Observation
  • Sampling
  • Surface Energy
  • Surface Properties
  • Universities

Fields of Study

  • Environmental science

Readers

  • Combustion and Flow Dynamics.
  • Ocean-Atmosphere Mesoscale Modeling, Data Assimilation, and Flux Boundary Layers