Evaporation from sparse crops-an energy combination theory

✍ Scribed by W. James Shuttleworth; J. S. Wallace

• Book ID: 104575607
• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 1016 KB
• Volume: 111
• Category: Article
• ISSN: 0035-9009
• DOI: 10.1002/qj.49711146910

✦ Synopsis

A one-dimensional model is adopted to describe the energy partition of sparse crops. Theoretical development of this model yields a combination equation which describes evaporation in terms of controlling resistances associated with the plants, and with the soil or water in which they are growing. The equation provides a simple but physically plausible description of the transition between bare substrate and a closed canopy. Although the aerodynamic transfer resistances for incomplete canopies have, as yet, no experimental justification, typical values, appropriate to a specimen agricultural crop and soil, are shown to have limited sensitivity in the model. Processes which require further study if the equation is to be used to calculate evaporation throughout a crop season are also discussed.