%0 Journal Article
%1 ThomasRevPMC
%A Thomas, G. E.
%D 1991
%J Reviews of Geophysics
%K ATMOSPHERE CLOUDS GRAVITY-WAVE HIGH-LATITUDE LEO MESOPAUSE MESOSPHERE MIDDLE NOCTILUCENT POLAR SUMMER
%N 4
%P 553-575
%T Mesospheric clouds and the physics of the mesopause region
%V 29
%X During the last decade, new satellite observations of polar mesospheric clouds and ground-based radar and lidar sounding of the high-latitude summertime mesosphere have stimulated new interest in this highly unusual atmospheric region. Computer simulations indicate that the ice condensation model for mesospheric cloud formation is correct in broad outline. This review contains a brief historical account of early mesospheric cloud studies with an emphasis on the two main theories: cosmic dust and ice condensation models. Current topics are described, including wave-cloud interactions, the dynamics and momentum budget of the high-latitude polar mesosphere, new satellite observations, polar mesospheric summer radar echoes, heterogeneous chemistry, and implications of apparent secular changes in cloud brightness for global change of the atmosphere as a whole. There are major uncertainties in our theoretical understanding of the ice formation process, particularly in how the ice particles are nucleated. Future progress will require new research efforts in three separate directions: observations (ground based, rocket, and satellite), laboratory experiments, and theoretical modeling.