On the structure of the trade wind moist layer
Malkus, Joanne Starr
MetadataShow full item record
The trade-wind moist layer is itself subdivided in the vertical into two superposed layers of different convective regime, because of the occurrence of water vapor condensation at about 600-700 m above the tropical oceans. Below the condensation level, in the so-called "subcloud" layer, unsaturated convective turbulence predominates. Eddies 50-150 m across are characteristic and recent studies suggest that larger scales of motion with dimensions 10-50 km (size of cloud groups) are also significant. No evidence of cloud-scale motions below cloud base have been found, except in precipitating downdrafts. Above the condensation level, cumulus convection is the major transport process; small-scale turbulence is confined to the neighborhood of clouds, which form in bunches separated by wider, weakly subsiding clear areas. The lower four-fifths of the subcloud layer is well-stirred and has been christened the "mixed layer". The lapse rate is close to dry adiabatic and the moisture content of the air is nearly constant with height, decreasing only 3-6% from 15m above the sea to its top at about 550 m. The thickness of the mixed layer commonly shows variations of 20% in space and as much as 100% in time, with extreme day-to-day variations of about 300-700 m. Recent evidence suggests that its space variations on a 10-50 km scale are associated with the bunchy grouping of trade cumuli. It appears that the clouds are grouped in places where the mixed layer is thickened, reaching close to the condensation level of the air within it. The trade-wind mixed layer thus plays the crucial role of a "valve" in the earliest phases of the atmosphere's energy supply. Its structure regulates both the input from the sea below through evaporation and the output aloft through cumulus formation. The present study has therefore been divided into three parts. Part I examines the structure of air below cloud; Part II is concerned with the features of the cloud layer and cumulus convection; and Part III attempts to construct a physical model of the operation of the moist layer as a whole.
Suggested CitationBook: Malkus, Joanne Starr, "On the structure of the trade wind moist layer", Papers in Physical Oceanography and Meteorology, v.13, no.2, 1958-08, DOI:10.1575/1912/1065, https://hdl.handle.net/1912/1065
Showing items related by title, author, creator and subject.
Farber, Stephen; Costanza, Robert; Childers, Daniel L.; Erickson, Jon; Gross, Katherine; Grove, J. Morgan; Hopkinson, Charles S.; Kahn, James; Pincetl, Stephanie; Troy, Austin; Warren, Paige; Wilson, Matthew (American Institute of Biological Sciences, 2006-02)This article outlines an approach, based on ecosystem services, for assessing the trade-offs inherent in managing humans embedded in ecological systems. Evaluating these trade-offs requires an understanding of the biophysical ...
Remote acoustic sensing of the particulate phase of industrial chemical wastes and sewage sludge : report on the seasonal variability of the dispersion of the particulate phase as observed from three cruises, July 1977, January-February 1978, and April 1978 Orr, Marshall H.; Baxter, Lincoln; Hess, Frederick R. (Woods Hole Oceanographic Institution, 1980-01)The seasonal variability of the dispersion of the particulate phase of industrial chemical waste has been studied with acoustic backscattering techniques at Deep Water Dumpsite 106 (DWD 106). The vertical dispersion of ...
Ellis, Jeffrey P.; Kelley, Brian C.; Stoffers, Peter; Fitzgerald, Michael G.; Summerhayes, Colin P. (Woods Hole Oceanographic Institution, 1977-12)The purpose of this data file, which has been modelled after Hathaway (1971), is to make available most of the basic data that was collected as part of Woods Hole Oceanographic Institution's study of New Bedford Harbor. ...