Three‐Dimensional Modeling of the O<sub>2</sub>(<sup>1</sup>∆) Dayglow: Dependence on Ozone and Temperatures - INSU - Institut national des sciences de l'Univers Access content directly
Journal Articles Journal of Geophysical Research: Atmospheres Year : 2024

Three‐Dimensional Modeling of the O2(1∆) Dayglow: Dependence on Ozone and Temperatures

Franck Lefèvre
Alain Hauchecorne
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Jean-Loup Bertaux
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Future space missions dedicated to measuring CO on a global scale can make advantageous use 2 of the O2 band at 1.27 μm to retrieve the air column. The 1.27 μm band is close to the CO2 absorption bands at 1.6 and 2.0 μm, which allows a better transfer of the aerosol properties than with the usual O2 band at 0.76 μm. However, the 1.27 μm band is polluted by the spontaneous dayglow of the excited state O (1∆), which must be 2 removed from the observed signal. We investigate here our quantitative understanding of the O2(1∆) dayglow with a chemistry‐transport model. We show that the previously reported − 13% deficit in O2(1∆) dayglow calculatedwiththesamemodelisessentiallyduea− 20%to− 30%ozonedeficitbetween45and60km.Wefind that this ozone deficit is due to excessively high temperatures (+15 K) of the meteorological analyses used to drive the model in the mesosphere. The use of lower analyzed temperatures (ERA5), in better agreement with the observations, slows down the hydrogen‐catalyzed and Chapman ozone loss cycles. This effect leads to an almost total elimination of the ozone and O2(1∆) deficits in the lower mesosphere. Once integrated vertically to simulate a nadir measurement, the deficit in modeled O2(1∆) brightness is reduced to − 4.2 ± 2.8%. This illustrates the need for accurate mesospheric temperatures for a priori estimations of the O (1∆) brightness in 2 algorithms using the 1.27 μm band.
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insu-04558540 , version 1 (25-04-2024)




Mouhamadou Makhtar Ndiaga Diouf, Franck Lefèvre, Alain Hauchecorne, Jean-Loup Bertaux. Three‐Dimensional Modeling of the O2(1∆) Dayglow: Dependence on Ozone and Temperatures. Journal of Geophysical Research: Atmospheres, 2024, 129 (8), pp.e2023JD040159. ⟨10.1029/2023jd040159⟩. ⟨insu-04558540⟩
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