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First Results From the Retrieved Column O/N 2 Ratio From the Ionospheric Connection Explorer (ICON): Evidence of the Impacts of Nonmigrating Tides
Author(s) -
England Scott L.,
Meier R. R.,
Frey Harald U.,
Mende Stephen B.,
Stephan Andrew W.,
Krier Christopher S.,
Cullens Chihoko Y.,
Wu YenJung J.,
Triplett Colin C.,
Sirk Martin M.,
Korpela Eric J.,
Harding Brian J.,
Englert Christoph R.,
Immel Thomas J.
Publication year - 2021
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2021ja029575
Subject(s) - thermosphere , ionosphere , airglow , atmospheric sciences , middle latitudes , latitude , anomaly (physics) , amplitude , depth sounding , geology , environmental science , satellite , geodesy , geophysics , physics , oceanography , optics , astronomy , condensed matter physics
In near‐Earth space, variations in thermospheric composition have important implications for thermosphere‐ionosphere coupling. The ratio of O to N 2 is often measured using far‐UV airglow observations. Taking such airglow observations from space, looking below the Earth's limb allows for the total column of O and N 2 in the ionosphere to be determined. While these observations have enabled many previous studies, determining the impact of nonmigrating tides on thermospheric composition has proved difficult, owing to a small contamination of the signal by recombination of ionospheric O + . New ICON observations of far‐UV are presented here, and their general characteristics are shown. Using these, along with other observations and a global circulation model, we show that during the morning hours and at latitudes away from the peak of the equatorial ionospheric anomaly, the impact of nonmigrating tides on thermospheric composition can be observed. During March–April 2020, the column O/N 2 ratio was seen to vary by 3–4% of the zonal mean. By comparing the amplitude of the variation observed with that in the model, both the utility of these observations and a pathway to enable future studies is shown.