Density and temperature structure over northern Europe

Philbrick, C. R.; Schmidlin, F. J.; Grossmann, K. U.; Lange, G.; Offermann, D.; Baker, K. D.; Krankowsky, D.; Zahn, U. von

doi:10.1016/0021-9169(85)90131-x

Cited by 62 publications

(14 citation statements)

References 15 publications

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“…Anomalous diffusion occurred also in the trail near 105 and 110 km analyzed by . Strong layering in the lower thermosphere with stable and unstable regions has also been observed in high resolution temperature profiles (Philbrick et al, 1985;Hillert et al, 1994;Lehmacher et al, 2006). Our wind, temperature and trail observations confirm that the lower thermosphere is highly structured and shows clear deviations from laminar behavior.…”

Section: Anomalous Diffusion From 103 To 118 Kmsupporting

confidence: 81%

The Turbopause experiment: atmospheric stability and turbulent structure spanning the turbopause altitude

et al. 2011

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Abstract. Very few sequences of high resolution wind and temperature measurements in the lower thermosphere are available in the literature, which makes it difficult to verify the simulation results of models that would provide better understanding of the complex dynamics of the region. To address this problem the Turbopause experiment used four rockets launched over a period of approximately two hours from Poker Flat Research Range, Alaska (64 • N, 147 • W) on the night of 17-18 February 2009. All four rocket payloads released trimethyl aluminum trails for neutral wind and turbulence measurements, and two of the rockets carried ionization gauges and fixed-bias Langmuir probes measuring neutral and electron densities, small-scale fluctuations and neutral temperatures. Two lidars monitored temperature structure and sodium densities. The observations were made under quiet geomagnetic conditions and show persistence in the wind magnitudes and shears throughout the observing period while being modulated by inertia-gravity waves. High resolution temperature profiles show the winter polar mesosphere and lower thermosphere in a state of relatively low stability with several quasi-adiabatic layers between 74 and 103 km. Temperature and wind data were combined to calculate Richardson number profiles. Evidence for turbulence comes from simultaneous observations of density fluctuations and downward transport of sodium in a mixed layer near 75 km; the observation of turbulent fluctuations and energy dissipation from 87-90 km; and fast and irregular trail expansion at 90-93 km, and especially between 95 to 103 km. The regions of turbulent trails agree well with regions of quasi-adiabatic temperature gradients. Above Correspondence to: G. A. Lehmacher (glehmac@clemson.edu) 103 km, trail diffusion was mainly laminar; however, unusual features and vortices in the trail diffusion were observed up to 118 km that have not been as prevalent or as clearly evident in earlier trail releases.

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Section: Anomalous Diffusion From 103 To 118 Kmsupporting

confidence: 81%

The Turbopause experiment: atmospheric stability and turbulent structure spanning the turbopause altitude

et al. 2011

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Section: Discussionmentioning

confidence: 95%

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

Lehmacher¹,

Larsen²,

Collins³

et al. 2018

Preprint

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Abstract. 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. 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 (< 0.01%) at sub-meter resolution. The large-scale vertical temperature structure was very consistent between the four soundings. The mesosphere 5 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 variability 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 10 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 wind shears near 108 km, and combined with the observed temperature gradient, isolated regions of unstable Richardson numbers (0 < Ri < 0.25) 15were detected in the lower thermosphere. The experiment was launched into a bright auroral arc under moderately disturbed conditions (K p ∼ 5).

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“…While sensitive accelerometers on supersonic free-falling spheres have been used previously to successfully measure winds, densities and temperatures in the mesosphere and lower thermosphere (Philbrick et al, 1985), this experiment demonstrates that changes in atmospheric drag may be observed for much heavier, cylindrical payloads with a lowcost device, however, only in the denser mesosphere. A similar accelerometer experiment was flown on the German MAPHEUS-1 student mission (Stamminger et al, 2009), which appears less sensitive than our device.…”

Section: Appendix A: Accelerometer Data Analysismentioning

confidence: 97%

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

et al. 2018

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Abstract. Four mesosphere-lower thermosphere temperature and turbulence profiles were obtained in situ within ∼ 30 min and over an area of about 100 by 100 km during a sounding rocket experiment conducted on 26 January 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 (< 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 of 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 variability 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 −1 , 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 to +70 K were observed. Simultaneous wind measurements revealed extreme wind shears near 108 km, and combined with the observed temperature gradient, isolated regions of unstable Richardson numbers (0 < Ri < 0.25) were detected in the lower thermosphere. The experiment was launched into a bright auroral arc under moderately disturbed conditions (K p ∼ 5).

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Density and temperature structure over northern Europe

Cited by 62 publications

References 15 publications

The Turbopause experiment: atmospheric stability and turbulent structure spanning the turbopause altitude

The Turbopause experiment: atmospheric stability and turbulent structure spanning the turbopause altitude

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

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

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