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Assessment of Evaporation from Bare Soil by Infrared Thermometry
Author(s) -
BenAsher J.,
Matthias A. D.,
Warrick A. W.
Publication year - 1983
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1983.03615995004700020002x
Subject(s) - lysimeter , evaporation , environmental science , soil water , saturation (graph theory) , soil science , energy balance , infrared , hydrology (agriculture) , potential evaporation , atmospheric sciences , meteorology , geology , geotechnical engineering , mathematics , physics , optics , combinatorics , thermodynamics
A method is described to estimate daily soil water evaporation from a drying uniform bare soil. The method involves wind speeds ( u ) and midday infrared thermometric measurements of surface temperatures of the drying soil ( T d ) and a nearby reference dry soil ( T o ). Calculation of evaporation is made using a linear function of ( T o ‐T d ) and u derived from basic energy balance considerations. An experiment was conducted in Tucson, Ariz., to compare lysimeter‐measured values of evaporation with those estimated on the basis of the method. Three lysimeters (0.5 by 0.5 by 0.12 m) containing uniform soil were used in this experiment. One was kept wet (steady‐state saturation), one was air dry, and one was initially wetted and allowed to dry during a 21‐d interval in December 1981. Results showed a good agreement ( r 2 = 0.61) between the theoretical and measured values. The method is proposed for use in studies of field variability of soil water evaporation and is amenable to the utilization of remotely sensed data.