Microphysics of the mesosphere / lower thermosphere (MLT)

Noctilucent clouds (NLC) and polar mesosphere summer echoes (PMSE) are evidence of ice clouds in MLT altitude range. Owing to the fact that the properties of these ice clouds do strongly depend on the conditions of the background atmosphere, it has been speculated that observations of these phenomena could be used as an indicator for global long term change in the mesosphere. This, however, certainly requires a detailed and robust physical understanding of all the processes which are relevant for the creation and development of these clouds as well as a robust understanding of their effect on their environment.

Other microphysical process that takes place in the mesopause region is the formation of meteoric smoke particles. There is little observational evidence regarding the future of the metallic material after meteoric ablation. It is generally assumed that the metallic material recondenses within a few days to form tiny particles with a radius of a few nanometers, however this has not been conclusively confirmed. Some debris of meteors can be deposited in the mesosphere if ablation of meteor was not completed or if the fragmentation took a place during ablation process. We study such effects using a combination of ground-based radars as well as in-situ sensors on-board rockets.


  • Rapp, M., and G. E. Thomas, Modeling the microphysics of mesospheric ice particles: Assessment of current capabilities and basic sensitivities, J. Atmos. Sol. Terr. Phys., 68, 715–744, doi:10.1016/j.jastp.2005.10.015, 2006
  • Rapp, M., I. Strelnikova, Q. Li, N. Engler, and G. Teiser, Charged aerosol effects on the scattering of radar waves from he D-region, in Climate And Weather of the Sun-Earth System (CAWSES): Highlights from a priority program, edited by F.-J. Lübken, Springer, Dordrecht, The Netherlands, doi:10.1007/978-94-007-4348-9, 2012
  • Rapp, M., J. M. C. Plane, B. Strelnikov, G. Stober, S. Ernst, J. Hedin, M. Friedrich, and U.-P. Hoppe, In situ observations of meteor smoke particles (MSP) during the Geminids 2010: Constraints on MSP size, work function, and composition, Ann. Geophys., 30, 1661–1673, doi:10.5194/angeo-30-1661-2012, 2012