Evaporation Duct Height Measurements in the Mid-Atlantic,
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)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1978
- Accession Number
- ADA091851
Entities
People
- Christopher W. Fairall
- G. E. Schacher
- K. L. Davidson
- T. M. Houlihan
Organizations
- Naval Oceanographic Office