Modeling and observations of PMC/NLC in the mesopause region

Abstract:

The microphysical 3-d lagrangian ice model called LIMA (Leibniz-Institute Middle Atmosphere)-ICE is used to study the formation of ice layers (PMC/NLC) in the mesopause region at mid, high, and polar latitudes during summer.

We will show LIMA-ICE simulations of the thermal state at the summer upper mesosphere since 1961 until 2014 which are essential for ice layer formation. The NLC/PMC characteristics deduced from LIMA-ICE are validated with various data sets from satellite observations from AIM/SOFIE and SBUV, and lidar measurements (ALOMAR). LIMA nicely reproduces the mean characteristics of observed ice layers, e.g. occurrence rates, brightness, ice water content (IWC), ice particle size, height distribution of ice particles, etc. in variation with season, altitude, and latitude. Furthermore, we present some theoretical aspects of ice formation which will address methods how to analyse ice nucleation, ice particle size distribution, lifetime, and spatial transportation scales. Finally, we show some decadal long term trends in modeled PMC formation in comparison with satellite data (SOPHIE, SBUV) and NLC trends from visual observations.