Originally published in Trudy, Ukrainskii Nauchno-Issledovatelskii Gidrometeorologicheskii Insittut, vypusk 21, p. 16-22. Sponsored by the U.S. Army Electronic Proving Ground. Includes bibliographical references (p. 9)
It is well known that low air-mass stratus type cloudiness forms, in the same way as advection fog, as a rule, in stable warm moist air during its transport over the cold underlying surface. But at times such cloudiness or fog develops in the absence of warm advection when the necessary saturation is attained by means of radiational cooling and turbulent mixing. The important role of radiational cooling in the formation of low cloudiness is spoken for by the fact that it has a sufficiently well expressed diurnal course with a maximum frequency in the morning hours. In a previous report a method was proposed for an approximate calculation of the radiational factor in forecasting and in the diagnosis of advection fog and low cloudiness. It was shown in this work, that in the absence of warm advection and moisture and with intensity of turbulence, which does not change with time, and the formation of low cloudiness due to the influence of raidational cooling is possible. In this article some supplementary data are presented, verifying and refining the status in the previous report.