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The application of wet‐bulb potential temperature to air mass analysis. IV
Author(s) -
Hewson E. W.
Publication year - 1938
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49706427606
Subject(s) - clear air turbulence , air mass (solar energy) , warm front , homogeneity (statistics) , environmental science , moisture , turbulence , atmospheric sciences , water content , subsidence , potential temperature , air temperature , lapse rate , meteorology , geology , mechanics , geography , physics , boundary layer , mathematics , geomorphology , geotechnical engineering , statistics , structural basin
This paper describes:‐a The moisture content of subsiding polar continental air over North America, under conditions when there was no likelihood of an increase in the moisture content due to precipitation from overrunning air. Two situations of this type are discussed, and no evidence is found of any appreciable increase above 850 mb. b The degree of homogeneity in polar continental air masses. The vertical distributions of wet‐bulb potential temperature Θ 1 as observed nearly simultaneously at adjacent stations within an air mass are discussed in relation to their effect on the accuracy of computations of subsidence. c The vertical velocity of air in the warm sector of a depression. It is shown that in the warm sector considered, the ascent of the air near the surface was nearly twice as rapid as that at about 600 mb. The vertical velocity of the surface air was of the order of 4 cm./sec., and that of the air at about 600 mb. was of the order of 2 cm./sec. d The effect of turbulence in the air near the surface. The changes of temperature and moisture content in the surface layers of a moving air mass are discussed in the light of the theory of turbulence, as developed by Richardson and Taylor.