An Experimental Parameterization For Sensible Heat Flux And Computation Of Surface Air Temperature For Various Desert Areas
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Date
1976
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Abstract
The energy flux terms in the surface heat balance equation were computed using parameterizations and mean monthly temperature, precipitation, planetary albedo, cloudiness, and vapor pressure data for 85 very dry locations. The major flux terms, solar radiation absorbed (S), net longware radiation (I), and sensible heat flux (H), for January and July are presented for 60 stations in North Africa. Sensible heat exchange between the air and surface was then parameterized by a regression procedure using the mean ,monthly values computed as residuals in the heat balance equation. H was found to be a function of S and the proximity of the station to a major water body (D). Larger H surface losses occur for larger values of S and/or smaller values of D. The regression equation for H explains 96% of the variance of the original computations. Knowing approximate expressions for all the terms in the heat balance equation, mean monthly surface air temperature was computed to test the efficacy of the H parameterization. The computed temperatures (Tc) show a combination of systematic and random deviations from the observed temperatures to the extent that the average root-mean-square error of Tc for all stations is 10°C. Thus, the derived expression for H has limited computational usefulness. Improvements in the parameterization could perhaps be made by replacing constants with simple functions or by dividing the stations into two or more geographical regions for separate study.
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Program year: 1975/1976
Digitized from print original stored in HDR
Digitized from print original stored in HDR
Keywords
energy flux, solar radiation absorbed, net longware radiation, sensible heat flux, North Africa, desert