Abstract
The details of the processes by which heat is transported through the lower atmosphere are, for the most part, still obscure although our knowledge of typical temperature distributions near the ground is now well founded, thanks chiefly to the researches of Johnson (1929), Best (1935), Flower (1936) and Johnson and Heywood (1938). These investigations establish in considerable detail the principal features of the mean temperature field from 2Β·5 cm. to 87 m., so that the data for the elucidation of the problems of heat transfer are undeniably available, but the complexity of the situation, depending as it must upon the joint effects of radiation, conduction and convection, is such that there is little hope that a comprehensive mathematical theory will be evolved for some time yet.
The present paper is an attempt to clarify certain aspects of the problem, and in particular to analyse the general nature of the flux of heat through the lower atmosphere on a clear day in summer. The conclusion is reached that to explain the type of heat flow which prevails in these conditions necessitates the consideration of the nature of the vertical currents due to buoyancy and their effect on the virtual coefficient of conduction, and for this purpose a theoretical treatment is proposed which differs in many ways from those previously advanced.