Direct measurements of atomic oxygen in the mesosphere and lower thermosphere using terahertz heterodyne spectroscopy

Richter, Heiko
Buchbender, Christof ORCIDiD
Güsten, Rolf
Higgins, Ronan
Klein, Bernd
Stutzki, Jürgen
Wiesemeyer, Helmut
Hübers, Heinz-Wilhelm ORCIDiD

DOI: https://doi.org/10.1038/s43247-020-00084-5
Persistent URL: http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/11192
Richter, Heiko; Buchbender, Christof; Güsten, Rolf; Higgins, Ronan; Klein, Bernd; Stutzki, Jürgen; Wiesemeyer, Helmut; Hübers, Heinz-Wilhelm, 2021: Direct measurements of atomic oxygen in the mesosphere and lower thermosphere using terahertz heterodyne spectroscopy. In: Communications Earth & Environment, 2, 1, DOI: https://doi.org/10.1038/s43247-020-00084-5. 
 
Richter, Heiko; German Aerospace Center (DLR), Institute of Optical Sensor Systems, Berlin, Germany
Buchbender, Christof; I. Physikalisches Institut der Universität zu Köln, Köln, Germany
Güsten, Rolf; Max-Planck-Institut für Radioastronomie, Bonn, Germany
Higgins, Ronan; I. Physikalisches Institut der Universität zu Köln, Köln, Germany
Klein, Bernd; Max-Planck-Institut für Radioastronomie, Bonn, Germany
Stutzki, Jürgen; I. Physikalisches Institut der Universität zu Köln, Köln, Germany
Wiesemeyer, Helmut; Max-Planck-Institut für Radioastronomie, Bonn, Germany
Hübers, Heinz-Wilhelm; Department of Physics, Humboldt-Universität zu Berlin, Berlin, Germany

Abstract

Atomic oxygen is a main component of the mesosphere and lower thermosphere of the Earth, where it governs photochemistry and energy balance and is a tracer for dynamical motions. However, its concentration is extremely difficult to measure with remote sensing techniques since atomic oxygen has few optically active transitions. Current indirect methods involve photochemical models and the results are not always in agreement, particularly when obtained with different instruments. Here we present direct measurements—independent of photochemical models—of the ground state 3P13 P2 fine-structure transition of atomic oxygen at 4.7448 THz using the German Receiver for Astronomy at Terahertz Frequencies (GREAT) on board the Stratospheric Observatory for Infrared Astronomy (SOFIA). We find that our measure ments of the concentration of atomic oxygen agree well with atmospheric models informed by satellite observations. We suggest that this direct observation method may be more accurate than existing indirect methods that rely on photochemical models.


Atomic oxygen concentrations in the upper atmosphere can be measured directly with an airborne terahertz heterodyne spectrometer. This approach is probably more accurate than indirect estimates from photochemical models, according to a comparison of the two methods.