This project deals with the physics and chemistry of odd oxygen species in the Earth's upper atmosphere, more precisely in the mesopause region. This atmospheric region hosts a variety of atmospheric airglow emissions that are driven directly or indirectly by atomic oxygen. Several of these emissions are routinely used to remotely sense the composition of this atmospheric region or its thermal structure. However, there is a lack in our scientific understanding of the excitation mechanisms of these emissions. The current projects aims at investigating the relevant excitation mechanisms and improve their scientific understanding. This will be achieved by combining satellite airglow observations with dedicated model simulations with a 3-D model coupled to an airglow module allowing simulations of  O, O2 and OH airglow emissions. The envisaged outcome of the project includes a 10-year dataset of validated atomic oxygen profiles in the mesopause region, quantification of long-term and solar cycle signatures and updated photochemical models to retrieve atomic oxygen from remote sensing observations of airglow emissions by O, O2 as well as OH. 

KIT Karlsruhe:  Dr. Miriam Sinnhuber, Dr. Tilo Fytterer (website of the KIT team: http://www.imk-asf.kit.edu/msk.php)

EMAU Greifswald: Prof. Dr. Christian von Savigny, Olexandr Lednyts'kyy

03/2016 - 02/2019

SCIAMACHY observations of the green line emission in the terrestrial nightglow are employed to retrieve Volume Emission Rate (VER) profiles, which are employed to retrieve density profiles of atomic oxygen in the ground state ([O(3P)]) in the MLT region. The data has been averaged in latitude bins shown in the column 'Latitude range (degree, N)' using the available number of the employed spectral measurements shown in the column '# of spectra'. VER profiles shown in the column 'VER (photon cm-3 s-1)' are provided in the whole altitude range shown in the column 'Altitude (km)'. [O(3P)] profiles are provided where profiles obtained using SABER/TIMED required for our [O(3P)] retrievals were available. [O(3P)] profiles retrieved using the well-known cubic equation (WCE) are shown in the column 'O3P_WCE (atom cm-3)', and those retrieved using the extended cubic equation (ECE) are shown in the column 'O3P_ECE (atom cm-3)'. The result of arithmetical averaging of both [O(3P)] profiles are shown in the column 'O3P_AVE (atom cm-3)'. A description of the retrieval procedure can be found in the following article:

• Lednyts'kyy, O., von Savigny, C., Eichmann, K.-U., and Mlynczak, M. G.: Atomic oxygen retrievals in the MLT region from SCIAMACHY nightglow limb measurements, Atmos. Meas. Tech., 8, 1021-1041, doi:10.5194/amt-8-1021-2015, 2015.

The [O(3P)] retrievals were validated using in situ [O(3P)] measurements obtained during two rocket campaigns. The left panel of Fig. 4 in Lednyts'kyy and von Savigny (2020) and that of Fig. 10 in Lednyts'kyy et al. (2019) show the three [O(3P)] profiles retrieved and compared with in situ [O(3P)] profiles measured during the campaigns ETON and WAVE2004, respectively, see the following articles for details:

• Lednyts'kyy, O. and von Savigny, C.: Photochemical modeling of molecular and atomic oxygen based on multiple nightglow emissions measured in situ during the Energy Transfer in the Oxygen Nightglow rocket campaign, Atmos. Chem. Phys., 20, 2221–2261, doi.org/10.5194/acp-20-2221-2020, 2020.
• Lednyts'kyy, O., C. von Savigny, M. Sinnhuber, N. Iwagami and M. Mlynczak, Multiple Airglow Chemistry approach for atomic oxygen retrievals on the basis of in-situ nightglow emissions, J. Atmos. Sol.-Terr. Phys., 194,  https://doi.org/10.1016/j.jastp.2019.105096, 2019.