THEORETICALLY PERMISSIBLE ALTITUDE AND SEASONS FOR THE OCCURRENCE OF CLOUDS NEAR THE MESOPAUSE.

摘要

A thermodynamic exclusion principle is used to determine those regions in the earth's upper atmosphere where the formation of clouds due to condensation or sublimation of water vapor is or is not possible. The probability of occurrence of such clouds is then determined from model atmospheres as a function of altitude for different latitudes and seasons. The theoretical results correspond well with actually observed locations,frequencies,and altitudes of noctilucent clouds. It is shown that statistical analysis of certain noctilucent cloud data should not only permit experimental tests of the theoretical study,but also provide,by inference,information about variations of the mesopause altitude with latitude,season,and solar activity. (Author)