Nighttime mean one month sliding averaged values at peak of the OHv=2 layer calculated by Eq. (1) at middle (40°N) latitudes: a) [OHv=2], b) height of peak, c) [O], and d) temperature.

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... Equations derived above provide some predictions and can be applied for analysis, which we illustrate below. The terrestrial OH * airglow layer demonstrates annual and semiannual variations (e.g., Gao et al., 2010). Similar variations can be expected from the Martian OH* due to seasonal changes in [O], air number density and temperature. Fig. 2 shows time series of nighttime one-month sliding averaged values at the peak of the OHv=2 layer calculated with (1) at middle (40°N) latitudes: a) [OHv=2], b) the height of the peak, c) [O], and d) temperature. It is seen that the concentration and the height of the peak at the northern middle latitude vary seasonally with the maxim ...

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... b) the height of the peak, c) [O], and d) temperature. It is seen that the concentration and the height of the peak at the northern middle latitude vary seasonally with the maxim concentrations and lowest height occurring during the first half of the year (Ls=0°-180°). The amplitude of the annual height variation on Mars is more than 20 km (Fig. 2b), which by several times exceeds that near the Earth mesopause (~5-10 km). The figures show a clear anticorrelation between the [OHv=2] and the height of the peak, as also follows from (8). Since volume emission is linearly proportional to the [OH * ], this points out to an anticorrelation between the emission and the height of the ...

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... at winter. This is because the main driver for OH * layer on Earth is O, which is transported downward in winter and upward in summer. On Mars, the layer behavior is determined additionally by air density variations. Seasonal changes of temperature play a minor role in the annual cycle of OH * , since it varies only by about 15 K over the year (Fig. ...

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... of actual (modeled) values from averaged. (15) as solid and dashed lines, respectively. The variations of temperature (red lines) play a minor role, whereas variations due to O and air concentrations are of the same order (variation due to air number density is slightly larger) with action in antiphase. The first peak of OH * at Ls~40°-50° (Fig. 2a) is determined primarily by growth of air number density (blue line) and secondary due to temperature decline ( Fig. 2d and red line on Fig. 3). The secondary peak of [OH * ] at Ls~150° (Fig. 2a) is primarily determined by growth of [O] (green line) when declining air concentration and growing temperature act in opposite direction. The ...

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... (red lines) play a minor role, whereas variations due to O and air concentrations are of the same order (variation due to air number density is slightly larger) with action in antiphase. The first peak of OH * at Ls~40°-50° (Fig. 2a) is determined primarily by growth of air number density (blue line) and secondary due to temperature decline ( Fig. 2d and red line on Fig. 3). The secondary peak of [OH * ] at Ls~150° (Fig. 2a) is primarily determined by growth of [O] (green line) when declining air concentration and growing temperature act in opposite direction. The variations due to 2 nd momenta are weaker and they do not exceed ...

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... are of the same order (variation due to air number density is slightly larger) with action in antiphase. The first peak of OH * at Ls~40°-50° (Fig. 2a) is determined primarily by growth of air number density (blue line) and secondary due to temperature decline ( Fig. 2d and red line on Fig. 3). The secondary peak of [OH * ] at Ls~150° (Fig. 2a) is primarily determined by growth of [O] (green line) when declining air concentration and growing temperature act in opposite direction. The variations due to 2 nd momenta are weaker and they do not exceed ...