Current understanding of mesospheric transport processes

Abstract
The chemistry and transport processes taking place in the mesosphere (approximately 50—85 km altitude) are strongly coupled. In recent years, the physical mechanisms influencing the transport processes of the mesosphere have become better understood, through both theoretical and observational studies. Perhaps most importantly, a theoretical framework for describing the momentum deposition and diffusion due to breaking small-scale gravity waves has been developed and shown to result in thermal, chemical and dynamical structure that closely resembles observations. The transport due to planetary waves and tides has also been the subject of study. In this paper, the transport processes influencing mesospheric distributions of chemical constituents are briefly reviewed.