Boundary of Nighttime Ozone Chemical Equilibrium in the Mesopause Region From SABER Data: Implications for Derivation of Atomic Oxygen and Atomic Hydrogen

Abstract

In this study, the criterion for validity of the nighttime ozone chemical equilibrium assumption in the mesopause region is applied to Sounding of the Atmosphere using Broadband Emission Radiometry data for the year 2004 to define the boundary of this equilibrium. We demonstrate that the boundary varies within the range of 77–86 km depending on season and latitude and the retrieval of atomic oxygen from the equilibrium assumption below this boundary leads to significant (up to 5–8 times) underestimation of this component's concentration in the range of 80–85 km. However, this fact does not influence the subsequent atomic hydrogen retrieval.

Consistent Nighttime Atomic Oxygen Concentrations From O2A‐band, O(1S) Green‐Line, and OH Airglow Measurements as Performed by SCIAMACHY

“…A large negative bias of up to 40% is observed in February below 87 km at about 30 • N, and in April at midlatitudes in the southern hemisphere. Kulikov et al (2019) highlights that atomic oxygen, as derived from vibrationally excited OH, obtains a large uncertainty at low altitudes due to a breakdown in the chemical equilibrium of ozone production and loss during nighttime. We applied their criteria to the data presented in this work to evaluate whether this could explain the differences between the atomic oxygen datasets based on O 2 A-band and OH emissions.…”

Nighttime O(<sup>1</sup>D) distributions in the mesopause region derived from SABER data

“…(4). At this, we use also the analytical criterion (Kulikov et al, 2018) that allows the localization of the lower boundary of nighttime ozone chemical equilibrium (Kulikov et al, 2019) with the use of SABER data.…”

The 2‐Day Photochemical Oscillations in the Mesopause Region: The First Experimental Evidence?

“…The SABER database for the year 2003 includes ∼320,000 sets of nighttime profiles of For each set, we defined the local position of the NOCE boundary (pressure level eq p ) and the abovementioned criteria of 2DPO were tested only for the upper part of the profiles corresponding to  eq p p . Note that, following the conclusions of Kulikov et al (2019), this height restriction is required for correct evaluation of  HO x and  O due to underestimation of O concentration at  eq p p , whereas H data are suitable within the whole pressure interval. As a result, we found N b = 1,740 H profiles satisfying the criteria of 2DPO (i.e., in the regime of "high night H"), also in relatively wide ranges of latitude, longitude, and day of the year 2003.…”