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Direct Interception of Cloud Water on Lanaihale, Hawaii
Author(s) -
Ekern Paul C.
Publication year - 1964
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/sssaj1964.03615995002800030035x
Subject(s) - interception , environmental science , hydrology (agriculture) , elevation (ballistics) , harp , meteorology , atmospheric sciences , geology , geography , ecology , physics , geometry , geotechnical engineering , mathematics , quantum mechanics , biology
Lanai, a relatively dry island, lies in the trade wind flow downstream from Maui and Molokai and is peculiarly adapted to a demonstration of the amount of water that can be gathered by direct interception from clouds. An observation station was established at the 2,750‐foot level on Lanaihale in July 1955, and maintained for 3 years. The water collected over the 3 years by a network of rain gauges set beneath a Norfolk Island pine tree averaged 391 inches while rainfall in the open was only 149 inches. Since the tree also intercepted some rainfall, a net of 30 inches is suggested as the annual gain from cloud water interception. A wire harp kept oriented into the wind by a vane gathered 1,706 inches of water while rainfall alone was 97 inches. The harp had a vertical silhouette 27.5 times the area of the standard rain gauge in which the catch was measured. A 15‐ to 20‐inch gain per unit vertical area exposed is suggested as the annual direct cloud interception by the harp. Identical catchers of aluminum louver mounted at several elevations up to 30 feet above the ground gave an increased catch greater than the increase of wind with elevation.