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Diurnal Variation of Surface Fluxes During Thorough Drying (or Severe Drought) of Natural Prairie
Author(s) -
Brutsaert Wilfried,
Chen Daoyi
Publication year - 1996
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/96wr00995
Subject(s) - daytime , environmental science , evaporation , potential evaporation , atmospheric sciences , bowen ratio , latent heat , diurnal temperature variation , diurnal cycle , flux (metallurgy) , dimensionless quantity , climatology , sensible heat , meteorology , geography , geology , physics , chemistry , thermodynamics , organic chemistry
Experimental data recorded over a natural tallgrass prairie during the later stages of drying in the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment‐1987 showed (1) that the total daily values of evaporation exhibited a kind of second stage of drying behavior with a t −½ dependency at the daily timescale and (2) that this day‐to‐day evolution was modulated by the available energy at the surface, that is, the hourly radiation input. This allowed a simple description of the phenomenon by combining a desorptive diffusion‐type parameterization for the total daily evaporation or for its dimensionless counterpart (such as Priestley and Taylor's α, the evaporative fraction, and a few others), with an assumption of self‐preservation in the surface energy budget during the daytime hours. The resulting formulation, which involves two timescales, a daily and an hourly, was able to reproduce daytime hourly flux values over a 2‐week period of intensive drying. The method can also be useful in the disaggregation of daily, or even weekly, evaporation into hourly values.