Title: Evaporation in sheltered areas as influenced by windbreak porosity
Abstract: Evaporation was measured with atmometers located from 6 H (H is height of windbreak) windward (upwind) to 12 H leeward (downwind) of a 2.44 m (8 ft.) high windbreak. Evaporation, wind speed, and other associated micro-meteorological measurements were made when the wind direction was perpendicular ± 25° to the windbreak. With less porous windbreaks, minimum leeward evaporation occurred closer to the windbreak and, after reaching minimum, tended to increase more quickly than with more porous windbreaks. Minimum evaporation leeward of windbreaks 60, 40, and 0% porous occurred at about 4.5 H, 3.5 H, and immediately adjacent to the windbreak, respectively. At 4 H leeward of the solid windbreak, evaporation had recovered to 92% of open-field evaporation, whereas at 4 H leeward of 40 and 60% porous windbreaks, evaporation rates were 65 and 75% of open-field evaporation, respectively. Lowest relative evaporation over the observation region from 6 H windward to 12 H leeward was achieved with a 40% porous barrier. The windbreaks reduced evaporation in proportion to wind speed reduction. Data from measuring evaporation with atmometers agreed fairly well with data calculated with a revised combination model for instantaneous potential evaporation rate.
Publication Year: 1970
Publication Date: 1970-01-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 38
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