Structure function analysis of chemical tracer trails in the mesosphere‐lower thermosphere region

Roberts, Brenden; Larsen, M. F.

doi:10.1002/2013jd020796

Cited by 15 publications

(24 citation statements)

References 19 publications

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“…However, as pointed out in the previous section, regions of low stability may be rather void of mediumscale gravity wave breaking. A closer examination of the structure function derived from the TMA images (Roberts and Larsen, 2014) is needed to shed further light on the nature of the turbulence near the turbopause.…”

Section: Discussionmentioning

confidence: 99%

“…Below ∼ 103 km, the trails often develop billows of large and small sizes due to atmospheric turbulence (e.g., Blamont and de Jager, 1961;Roberts and Larsen, 2014). A very clear example can be seen in both downleg trails as viewed again from north from Toolik Lake (Fig.…”

Section: Buoyancy Frequency and Turbulencementioning

confidence: 99%

“…Modeling results show furthermore that such regions are less likely a location of strong wave breaking and turbulence generation, since medium-scale waves are evanescent in these regions (Jonathan Snively, personal communication, 2018). Roberts and Larsen (2014) used the entire downleg trail below the turbopause to determine the structure function coefficient as a function of scale size, while the largescale temperature structure was unknown. Our case presents an opportunity to study the evolution of the structure function under known stability conditions.…”

Section: Buoyancy Frequency and Turbulencementioning

confidence: 99%

“…We follow the methods developed for neutral density measurements in the mesosphere and lower thermosphere Lübken et al (1993), Rapp et al (2001), Strelnikov et al (2003). We also include results from simultaneous chemiluminescent trimethyl aluminum (TMA) releases, including horizontal winds, Richardson numbers and examples of turbulent structure in the trails (Larsen, 2002;Roberts and Larsen, 2014). Our paper is organized as follows.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Discussionmentioning

confidence: 99%

Section: Buoyancy Frequency and Turbulencementioning

confidence: 99%

Section: Buoyancy Frequency and Turbulencementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2018

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“…Below ∼103 km, the trails often develop billows of large and small sizes due to atmospheric turbulence (e.g., Blamont and de Jager, 1961;Roberts and Larsen, 2014). A very clear example can be seen in both downleg trails as viewed from Toolik Lake…”

mentioning

confidence: 99%

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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Polar mesospheric horizontal divergence and relative vorticity measurements using multiple specular meteor radars

Chau

Stober

Hall³

et al. 2017

Radio Science

111

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We present the first horizontal divergence and relative vorticity measurements at polar mesospheric altitudes measured from the ground. Our technique relies on combining information from two specular meteor radars (SMRs) separated 130 km at polar latitudes, specifically, the Andenes and Tromsø radars in northern Norway. The resulting values are obtained over a region that spans an approximate area of 400 km diameter at mesospheric altitudes. The temporal and vertical resolution are 1 h and 2 km in altitude. The technique not only allows to obtain the gradient terms of the horizontal wind, that in turn are used to derive the horizontal divergence and relative vorticity, but also improves the horizontal sampling compared to single SMRs. Synthetic data are used to qualitatively test the technique and identify potential sources of biases on the resulting measurements. For example, we have found that an apparent large mean vertical velocity is obtained, after averaging many days, if there is a persistent divergent field. We present a climatology of the resulting wind field parameters from 12 years of continuous observations and focus on the summer results. We found a persistent altitudinal pattern in both the horizontal divergence and relative vorticity fields during all northern hemispheric summers. The horizontal divergence is mainly positive decreasing in magnitude below ∼86 km, and the relative vorticity is negative/positive below/above ∼88 km over northern Norway.

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Structure function analysis of chemical tracer trails in the mesosphere‐lower thermosphere region

Cited by 15 publications

References 19 publications

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

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

Polar mesospheric horizontal divergence and relative vorticity measurements using multiple specular meteor radars

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