Boundary-Layer Meteorology

, Volume 25, Issue 2, pp 171–191

Modulation of heat flux by different scales of advection in an urban environment

  • J. K. S. Ching
  • J. F. Clarke
  • J. M. Godowitch
Article

DOI: 10.1007/BF00123973

Cite this article as:
Ching, J.K.S., Clarke, J.F. & Godowitch, J.M. Boundary-Layer Meteorol (1983) 25: 171. doi:10.1007/BF00123973

Abstract

Sensible heat flux data obtained from the U.S. Environmental Protection Agency's Regional Air Pollution Study in St. Louis, Missouri are presented and discussed. Large spatial variations exist in heat flux on both a land-use scale and the urban scale. Arguments based upon empirical data and sampling theory show that estimates of heat flux representative of an upwind fetch lx require a minimum observation height proportional to z3/4. The influence of advection on the magnitude of the heat flux is also explored for both the urban and sub-urban or land-use scales. The data clearly indicate that advection can strongly modulate and even dominate the vertical heat flux above surfaces in areas which maintain large horizontal temperature gradients. The advection contribution is positive for cold air advection and negative for warm air advection, and may result from either the urban heat island or land-use mesoscale features. The depth of advective influence is directly proportional to the horizontal scale of the phenomenon and inversely proportional to horizontal temperature gradient.

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Copyright information

© D. Reidel Publishing Co 1983

Authors and Affiliations

  • J. K. S. Ching
    • 1
  • J. F. Clarke
    • 1
  • J. M. Godowitch
    • 1
  1. 1.Meteorology and Assessment DivisionEnvironmental Sciences Research Laboratory, Environmental Protection AgencyResearch Triangle ParkUSA

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