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Field Test of Warm Fog Dispersal System to Support Marine Corps Helicopter Operations

Descriptive Note:

[Technical Report, Technical Report]

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Warm fog dispersal techniques using helicopter downwash mixing and hygroscopic seeding were successfully tested to a limited degree on fog and low stratus. The equipment, procedures and nomograms for helicopter application of hygroscopic seeding materials are described as they were developed in three field tests. In August 1970 helicopter seeding apparatus and hygroscopic materials handling techniques were tested at Elmira Airport, N.Y. At Lewisburg, W. Va., August 1971, the clearing capability of 2 medium weight helicopters CH-46 and H-3 were observed on 13 fog days. The last of the 3 tests was conducted at Cape Cod, 27 March to 21 April, 1972. During this test all ground support and airborne delivery tasks were performed by Marine Corps personnel. Weather conditions suitable for dispersal operations occurred on only one day, during which a useable clearing was created in low stratus, 650 feet thick. Results show that the effectiveness of fog dispersal by helicopter downwash was considerably enhanced when the fog or stratus layer was treated with hygroscopic seeding agent unsized urea in these particular tests. Some quantitative data and photographic coverage is presented.


Subject Categories:

  • Meteorology

Distribution Statement:

[A, Approved For Public Release]