Rd. Crago, COMPARISON OF THE EVAPORATIVE FRACTION AND THE PRIESTLEY-TAYLOR-ALPHAFOR PARAMETERIZING DAYTIME EVAPORATION, Water resources research, 32(5), 1996, pp. 1403-1409
This is a comparison between the evaporative fraction EF, which is the
surface latent heat flux divided by the available energy, and the Pri
estley-Taylor parameter alpha. It is shown for the First International
Satellite Land Surface Climatology Project (ISLSCP) Field Experiment
(FIFE) that the hypothesis that the midday values of EF and a: are the
same as their daytime average values must be rejected at the 0.05 lev
el of significance. However, correlations are high between the midday
and daytime average values for both variables. Daytime average latent
heat fluxes were estimated based on midday values of EF and alpha alon
g with daytime average available energy and equilibrium evaporation. I
n addition, the relationships between soil moisture and the midday and
daytime average values of EF and alpha were considered, along with th
e utility of these relationships in determining daytime total evaporat
ion. The conclusion is that at FIFE formulations based on EF are essen
tially interchangeable with corresponding formulations based on alpha.