Welcome to Physics Colloquium on Friday, 23rd October at 10.15. Coffee is served at 10:00. The lecture will take place at Ylistönrinne Campus in lecture hall KEM1. The talk begins at 10:15.
Physics colloquim provide students and staff with an opportunity to learn new topics and to discuss the latest research results.
Anyone interested is warmly welcome!
Title: Lighting Up the Edge of Space: From Atmospheric Dynamics to Spaceflight Emissions using High-Altitude Lidar
Speaker: Thorben Lüke-Mense(Leibniz Institute of Atmospheric Physics)
Abstract:
The middle and upper atmosphere, often playfully referred to as the "Ignorosphere," represents a critical observational gap. It is located too high for traditional weather balloons and too low for in-situ satellite measurements. To bridge this gap, ground-based Light Detection and Ranging (lidar) has proven to be an invaluable remote sensing tool.
Thorben H. Lüke-Mense, researcher at the Leibniz Institute of Atmospheric Physics (IAP) and responsible for the operation of the ALOMAR lidar observatory in Northern Norway, will provide insights into the capabilities and discoveries enabled by these powerful instruments. The presentation explores the physical and technical fundamentals of modern high-altitude lidar. By utilizing various light scattering mechanisms such as Rayleigh, Mie, and resonance scattering, these systems achieve exceptional spatial and temporal resolution. The talk will highlight the advanced technology driving these measurements, from state-of-the-art Nd:YAG lasers and highly optimized telescopes to polychromatic detection benches and completely newly developed Alexandrite ring lasers utilized for novel lidar concepts. These cutting-edge setups enable routine measurements up to the edge of space and sometimes even beyond.
A major scientific driver for these measurements is the ongoing climate change in Earth's middle and upper atmosphere, which significantly impacts the delicate balance of this region. Commissioned in 1994, the ALOMAR observatory holds one of the longest continuous lidar time series of over 30 years, providing an exceptional dataset for studying long-term atmospheric dynamics, gravity wave activity, and the formation of noctilucent clouds.
Beyond natural dynamics, a central theme of current observations is the growing environmental footprint of the booming space industry. The presentation will highlight measurements of spaceflight emissions, including the tracking of rocket launch exhaust plumes and the detection of vaporizing satellites and rocket components during atmospheric reentry. By identifying specific signatures, such as lithium plumes, these novel lidar observations provide critical evidence of how modern spaceflight is actively altering the environment at the very edge of space.
