ON THE QUESTION OF LOW-LEVEL CLOUD RESPONSE TO THE TEMPERATURE FIELD OF THE SEA SURFACE,
Abstract
Weekly averages of wind and air-sea temperature differences from ship reports averaged over four-degree quadrilaterals, revealed that increased wind velocities required larger air-sea temperature differences to maintain a maximum cloud amount at low cloud levels for spring and summer cases. During winter the situation was reversed with increased wind velocities requiring less air-sea temperatures to maintain above average cloud amounts. This was also reflected in the individual ship reports. A similar examination of cloud amounts at low levels and the air-sea temperature difference gave some indication that at least a 1C change in air-sea temperature difference was required to produce a change of 1/8 coverage in the low cloud field. Simple correlation coefficients between low clouds and air-sea temperature differences, wind, and dewpoint depression were small, with the correlation between clouds and wind being the highest with a value of 0.57. A seasonal trend of total cloud amount over the Gulf of Mexico from February to August existed in both ship and satellite data. Maximum cloudiness was observed in winter and summer, and a cloud minimum in April and May. The miminum cloud period reflected the presence of the subtropical high and the associated atmospheric subsidence rather than significantly decreased instability in the surface layers. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1968
- Accession Number
- AD0676231
Entities
People
- James E. Arnold
Organizations
- Texas A&M University