Effects of a large mesospheric temperature enhancement on the hydroxyl rotational temperature as observed from the ground

2001 ◽  
Vol 106 (A12) ◽  
pp. 30381-30388 ◽  
Author(s):  
Stella M. L. Melo ◽  
R. P. Lowe ◽  
W. R. Pendleton ◽  
M. J. Taylor ◽  
B. Williams ◽  
...  
Keyword(s):  
Rotational Temperature ◽  
Mesospheric Temperature ◽  
Temperature Enhancement

scholarly journals Effects of a large mesospheric temperature enhancement on the hydroxyl rotational temperature as observed from the ground

2001 ◽  
Vol 106 (A12) ◽  
pp. 30381-30388 ◽  
Author(s):  
Stella M. L. Melo ◽  
R. P. Lowe ◽  
W. R. Pendleton ◽  
M. J. Taylor ◽  
B. Williams ◽  
...  
Keyword(s):  
Rotational Temperature ◽  
Mesospheric Temperature ◽  
Temperature Enhancement

scholarly journals Case study of a mesospheric wall event over Ferraz station, Antarctica (62° S)

2011 ◽  
Vol 29 (1) ◽  
pp. 209-219 ◽  
Author(s):  
J. V. Bageston ◽  
C. M. Wrasse ◽  
R. E. Hibbins ◽  
P. P. Batista ◽  
D. Gobbi ◽  
...  
Keyword(s):  
Rotational Temperature ◽  
Time Interval ◽  
Imaging Spectrometer ◽  
Abrupt Decrease ◽  
Mesospheric Temperature ◽  
Wind Measurements ◽  
Components Analysis ◽  
Sky Imager ◽  
Mf Radar

Abstract. On 16–17 July 2007 during an observational campaign at Comandante Ferraz Antarctic Station (62° S, 58° W), a mesospheric wall was observed with an airglow all-sky imager. The wave appeared like an extensive dark region in the all-sky airglow images, with a large depletion in the OH emission. Simultaneous mesospheric winds measured with a MF radar at Rothera station and temperature profiles from SABER instrument, on board of TIMED satellite, were used to obtain the propagation condition of the wave. Wind measurements during four days, around the time of observation of the wave, are presented in order to discuss the type and consistence of the duct in which this wave was propagating. By using wavelet analysis and tidal amplitude components we found that 12 and 8 h components were the most important periodicities around the time interval of the wave observation. A collocated imaging spectrometer, for mesospheric temperature measurements, has been operated simultaneously with the all-sky imager. Direct effects of the mesospheric front have been seen in the spectrometric measurements, showing an abrupt decrease in both OH intensity and rotational temperature when the wave front passes overhead. The main contribution of the present work is the investigation of the type of duct in which the wall event was propagating. We found evidences for a thermal duct structure to support the mesospheric wall propagation. This result was obtained by two types of analysis: (a) the tidal components analysis and winds filtering (harmonic analysis), and (b) comparison between the terms of the m2 dispersion relation.

scholarly journals Polar Middle Atmospheric Responses to Medium Energy Electron (MEE) Precipitation Using Numerical Model Simulations

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 133
Author(s):  
Ji-Hee Lee ◽  
Geonhwa Jee ◽  
Young-Sil Kwak ◽  
Heejin Hwang ◽  
Annika Seppälä ◽  
...  
Keyword(s):  
Climate Model ◽  
Middle Atmosphere ◽  
Meridional Circulation ◽  
Stratospheric Ozone ◽  
High Energy ◽  
Chemical Changes ◽  
Temperature Changes ◽  
Mesospheric Temperature ◽  
High Energy Electrons ◽  
Circulation Changes

Energetic particle precipitation (EPP) is known to be an important source of chemical changes in the polar middle atmosphere in winter. Recent modeling studies further suggest that chemical changes induced by EPP can also cause dynamic changes in the middle atmosphere. In this study, we investigated the atmospheric responses to the precipitation of medium-to-high energy electrons (MEEs) over the period 2005–2013 using the Specific Dynamics Whole Atmosphere Community Climate Model (SD-WACCM). Our results show that the MEE precipitation significantly increases the amounts of NOx and HOx, resulting in mesospheric and stratospheric ozone losses by up to 60% and 25% respectively during polar winter. The MEE-induced ozone loss generally increases the temperature in the lower mesosphere but decreases the temperature in the upper mesosphere with large year-to-year variability, not only by radiative effects but also by adiabatic effects. The adiabatic effects by meridional circulation changes may be dominant for the mesospheric temperature changes. In particular, the meridional circulation changes occasionally act in opposite ways to vary the temperature in terms of height variations, especially at around the solar minimum period with low geomagnetic activity, which cancels out the temperature changes to make the average small in the polar mesosphere for the 9-year period.

Rotational temperature imaging of a leading-edge separation in hypervelocity flow

2019 ◽  
Author(s):  
Laurent M. Le Page ◽  
Matthew Barrett ◽  
Sean O’Byrne ◽  
Sudhir L. Gai
Keyword(s):  
Rotational Temperature ◽  
Leading Edge ◽  
Temperature Imaging ◽  
Edge Separation

Study of the (4–1) and (5–2) Hydroxyl Bands in the Night Airglow

1971 ◽  
Vol 49 (19) ◽  
pp. 2509-2517 ◽  
Author(s):  
A. W. Harrison ◽  
W. F. J. Evans ◽  
E. J. Llewellyn
Keyword(s):  
Seasonal Variation ◽  
Rotational Temperature ◽  
Band Intensity ◽  
K Value ◽  
Intensity Fluctuations ◽  
Single Night ◽  
Summer Minimum ◽  
Night Airglow

A 1 year study of the (4–1) and (5–2) hydroxyl bands in the night airglow near 1 μ has revealed a non-uniform rotational temperature across the P branch of each band. The temperature increases with K′ value. There is a pronounced seasonal variation of temperature showing a summer minimum and winter maximum. The average measured brightness for the (4–1) band is 4.6 kR (winter) and 3.5 kR (summer), and for the (5–2) band is 5.8 kR (winter) and 4.3 kR (summer). It is shown that the time-averaged total band intensity fluctuations during a single night are quite large, sometimes a factor of 2, and are not definitely correlated with the rotational temperature during the same period.

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