Univ. Colorado at Boulder Title: Polar Mesospheric Clouds and Their Atmospheric Environment The polar mesospheric clouds are created at heights near 85km by water vapor condensation onto ice particles. They are sometimes visible in midsummer at high latitudes as "Noctilucent Clouds" NSF has supported since 1983 the analysis of data on these clouds obtained by Dr Thomas and his team from the Solar Mesosphere Explorer satellite. This continuation proposal is to study the seasonal, latitudinal and north/south variability of cloud properties, in comparison with a model which includes the microphysics of nucleation. The proposed work is important for extending our understanding of the physics involved in polar mesospheric clouds, and also of the vertical and wave motions in the summer polar mesospheres, and of the differences between the Antarctic and Arctic mesospheres. The PI and his associates are well qualified to carry out the research, and their collaboration with others will enhance the results.
