Browsing by Author "Lloyd W. Gay"

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    Energy flux studies in a coniferous forest ecosystem
    (1972) Lloyd W. Gay
    The fluxes of thermal energy between the atmosphere and a young Douglas-fir forest were measured during two contrasting summer days, one cloudless and one overcast. The energy budget components were evaluated by the Bowen ratio method, with ceramic-wick psychrometers at the 26.16 m, 28.16 m, or 31.16 m levels. The maximum height of the tallest trees was 28 m, and the general level at the top of the closed canopy was about 22 m. Daily totals of the energy budget components (cal/cm^2) under cloudless skies on July 29, 1971, were: solar radiation, 584; net radiation, 410; change in storage, 5; convection, -135; and latent energy, -280. The albedo was 0.09 on both the clear and the overcast day. Analysis of the overcast conditions of July 31, 1971, yielded the following values: solar radiation, 171; net radiation, 134; change in storage, 6; convection, -39; and latent energy, -102. Problems of measurement and analysis are discussed. These include the storage term in the biomass, and the small gradients of potential temperature and vapor pressure above the canopy. Clear day gradients at noon, for example, were in the order of -0.03°C m~] and -0.03 mb m^-1. Techniques are presented for minimizing measurement errors.