We developed a system for frequency control and monitoring of pulsed high-power lasers. It works in real-time, controls the laser cavity length, and performs a spectral analyzes of each individual laser pulse. The motivation for this work was to improve the retrieval of Doppler winds measured by lidar in the middle atmosphere by taking the frequency stability of the lidar transmitter into account.

Noctilucent clouds (NLCs) are silvery clouds that can be viewed during twilight and indicate atmospheric conditions like temperature and water vapor in the upper mesosphere. High-resolution measurements from a remote sensing laser instrument provide NLC height, brightness, and occurrence rate since 2017. Most observations occur in the morning hours, likely caused by strong tidal winds, and NLC ice particles are thus transported from elsewhere to the observing location in the Southern Hemisphere.

Imagine you want to determine how quickly the pitch of a passing ambulance’s siren changes. If the vehicle is traveling slowly, the pitch changes only slightly, but if it is traveling fast, the pitch also changes rapidly. In a similar way, the wind in the middle atmosphere modulates the wavelength of atmospheric gravity waves. We have investigated the question of how strong the maximum wind may be so that the change in wavelength can still be determined with the help of wavelet transformation.

We used a lidar to measure polar mesospheric clouds from a balloon floating in the upper stratosphere. The thin-layered ice clouds at 83 km altitude are perturbed by waves. The high-resolution lidar soundings reveal small-scale structures induced by the breaking of those waves. We study these patterns and find that they occur very often. We show their morphology and discuss associated dynamical physical processes, which help to interpret case studies and to guide modelling.

We measured polar mesospheric clouds (PMCs), our Earth’s highest clouds at the edge of space, with a Rayleigh lidar from a stratospheric balloon. We describe how we derive the cloud’s brightness and discuss the stability of the gondola pointing and the sensitivity of our measurements. We present our high-resolution PMC dataset that is used to study dynamical processes in the upper mesosphere, e.g. regarding gravity waves, mesospheric bores, vortex rings, and Kelvin–Helmholtz instabilities.