Accession Number:

ADA091851

Title:

Evaporation Duct Height Measurements in the Mid-Atlantic,

Descriptive Note:

Corporate Author:

NAVAL OCEANOGRAPHIC OFFICE NSTL STATION MS

Report Date:

1978-08-01

Pagination or Media Count:

139.0

Abstract:

Atmospheric boundary layer measurements were made in the Mid-Atlantic aboard USNS KANE during February and March 1978. The results were analyzed to obtain Monin-Obukhov similarity parameters and EM wave train propagation characteristics within the evaporation ducts that overlay the sea surface. Evaporation duct heights Z varied between 2 and 25 meters during the cruise the mean Z value was 15 meters. In one instance, Z changed from 3 meters to 20 meters in about 4 hours following a frontal passage. A comparison of the results obtained using a simplified bulk method with those yielded by the established but technically taxing profile method did not convincingly establish that the bulk method could consistently predict accurate values of Z. Two factors predominate in controlling the duct height Z they are relative humidity and the air-sea temperature difference. Barring the development of radical new measurement techniques, the results of this work indicate that a program for routinely measuring Z is most likely to be obstructed by shortfalls in the quality of air-sea temperature difference data. Author

Subject Categories:

  • Meteorology
  • Radiofrequency Wave Propagation

Distribution Statement:

APPROVED FOR PUBLIC RELEASE