Boris Strelnikov

Atmospheric Band Fitting Coefficients Derived from Self-Consistent Rocket-Borne Experiment

16 Based on self-consistent rocket-borne measurements of temperature, densities of atomic 17 oxygen and neutral air, and volume emission of the Atmospheric Band (762 nm) we 18 examined the one-step and two-step excitation mechanism of OO2�bbΣgg� for night-time 19 conditions. Following McDade et al. (1986), we derived the empirical fitting coefficients, 20 which parameterize the Atmospheric Band emission OO2�bbΣgg − XXΣgg�(0,0). This allows to 21 derive atomic oxygen concentration from night-time observations of Atmospheric Band 22 emission OO2�bbΣgg − XXΣgg�(0,0). The derived empirical parameters can also be utilised for 23 Atmospheric Band modelling. Additionally, we derived fit function and corresponding 24 coefficients for combined (oneand two-step) mechanism. Simultaneous common volume 25

On the short-term variability of turbulence and temperature in the winter mesosphere

Four mesosphere-lower thermosphere temperature and turbulence profiles were obtained in situ within∼ 30 minutes and over an area of about 100 by 100 kilometers during a sounding rocket experiment conducted on January 26, 2015 at Poker Flat Research Range in Alaska. In this paper we examine the spatial and temporal variability of mesospheric turbulence in relationship to the static stability of the background atmosphere. Using active payload attitude control, neutral density fluctuations, a tracer for turbulence, were observed with very little interference from the payload spin motion, and with high precision 5 (< 0.01%) at sub-meter resolution. The large-scale vertical temperature structure was very consistent between the four soundings. The mesosphere was almost isothermal, which means more stratified, between 60 and 80 km, and again, between 88 and 95 km. The stratified regions adjoined quasi-adiabatic regions assumed to be well mixed. Additional evidence for vertical transport and convective activity comes from sodium densities and trimethyl aluminum trail development, respectively, which were both observed simultaneously with the in situ measurements. We found considerable kilometer scale temperature vari10 ability with amplitudes of 20 K in the stratified region below 80 km. Several thin turbulent layers were embedded in this region, differing in width and altitude for each profile. Energy dissipation rates varied between 0.1 and 10 mW/kg, which is typical for the winter mesosphere. Very little turbulence was observed above 82 km, consistent with very weak small-scale gravity wave activity in the upper mesosphere during the launch night. On the other hand, above the cold and prominent mesopause at 102 km, large temperature excursions of +40 K to +70 K were observed. Simultaneous wind measurements revealed extreme 15 wind shears near 108 km, and combined with the observed temperature gradient, isolated regions of unstable Richardson numbers (0