Winds and shears in the mesosphere and lower thermosphere: Results from four decades of chemical release wind measurements

Larsen, M. F.

doi:10.1029/2001ja000218

Cited by 229 publications

(321 citation statements)

References 62 publications

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“…The meridional transport rates required to reach the Antarctic are remarkably fast, reaching values four to five times larger than extant wind climatologies [Stevens et al, 2005] or first principles models. These high speed motions are, however, well within the range of winds observed with rocket-borne chemical releases, albeit on local scales [Larsen, 2002]. Plume events evolve differently and not all reach Polar Regions.…”

Section: Introductionmentioning

confidence: 92%

“…Water photolysis also takes place above that altitude, but hydrogen plume formation just two hours after launch is slower than that by direct H production from combustion. The portion of the plume between cross track pixels 0-30 appears to be caught in a wind curl reminiscent of those seen in chemical releases [Larsen, 2002]. The section between pixels 30-80 includes the main engine burn above 85 km, whose ground track is the solid black line in Figure 1 (right).…”

Section: Guvi Observations Of Lyman a Plumesmentioning

confidence: 99%

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Can molecular diffusion explain Space Shuttle plume spreading?

Meier

Plane

Stevens

et al. 2010

Geophysical Research Letters

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[1] The satellite-borne Global Ultraviolet Imager (GUVI) has produced more than 20 images of NASA Space Shuttle main engine plumes in the lower thermosphere. These reveal atomic hydrogen and, by inference, water vapor transport over hemispherical-scale distances with speeds much faster than expected from models of thermospheric wind motions. Furthermore, the hydrogen plumes expand rapidly. We find rates that exceed the horizontal diffusion speed at nominal plume altitudes of 104-112 km. Kelley et al. (2009) have proposed a 2-D turbulence mechanism to explain the observed spreading rates (and rapid advection) of the plumes. But upon further investigation, we conclude that H atom diffusion can indeed account for the observed expansion rates by recognizing that vertical diffusion quickly conveys atoms to higher altitudes where horizontal diffusion is much more rapid. We also find evidence for H atom production directly during the Shuttle's main engine burn. Citation: Meier, R. R., J.

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Section: Introductionmentioning

confidence: 92%

Section: Guvi Observations Of Lyman a Plumesmentioning

confidence: 99%

Can molecular diffusion explain Space Shuttle plume spreading?

Meier

Plane

Stevens

et al. 2010

Geophysical Research Letters

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“…[2] Very large winds and wind shears have been consistently observed for decades in the mesosphere and lower thermosphere (MLT) at low and mid-latitudes through sounding rocket measurements at various locations, which cover a wide range of longitudes, seasons, and local times [Larsen, 2002]. The winds often exceed 100 ms À1 between 95-115 km, with the maximum reaching 200 ms À1 .…”

Section: Introductionmentioning

confidence: 99%

On the large wind shear and fast meridional transport above the mesopause

Liu

2007

Geophysical Research Letters

107

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[1] Unexpectedly strong winds/shears and fast meridional transport above the mesopause have been revealed from previous rocket and satellite observations. Using Richardson number criteria for dynamic stability, we estimate the maximum wind shears allowable by the background static stability, which peaks above the mesopause. These maximum shears are in general agreement with the large wind shears inferred from the rocket measurements at low and mid-latitudes, indicating the close relationship between the latter and the stability constraint set by the background atmosphere. Diagnostic calculations also indicate that the meridional transport in this region may not be well understood solely by examining the mean meridional circulation, and large amplitude tides/ planetary waves can play an important role in the bulk transport of tracers. Strong stochastic winds, presumably due to gravity waves, do not seem to significantly change the large scale pattern of the transport but may extend the range of the tracer movement.On the large wind shear and fast meridional transport above the mesopause, Geophys. Res. Lett., 34, L08815,

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“…The altitude range between 100 and 110 km is known to be a region where large wind speeds are common, and the altitude immediately below the wind peak Published by Copernicus Publications on behalf of the European Geosciences Union. is known to have large and variable wind shears that are either unstable or close to instability (e.g., Larsen, 2002).…”

Section: Introductionmentioning

confidence: 99%

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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Winds and shears in the mesosphere and lower thermosphere: Results from four decades of chemical release wind measurements

Cited by 229 publications

References 62 publications

Can molecular diffusion explain Space Shuttle plume spreading?

Can molecular diffusion explain Space Shuttle plume spreading?

On the large wind shear and fast meridional transport above the mesopause

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

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