Temperature measurements from OH bands

Kvifte, G.

doi:10.1016/0032-0633(61)90090-3

Cited by 25 publications

(3 citation statements)

References 8 publications

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“…Langhoff et al (1986) transition probabilities are used to derive rotational temperatures as they are closest to the experimentally measured, temperature-independent line ratios determined for the OH(6-2) band using the same instrument in French et al (2000). Recent work by Noll et al (2019), show that these remain a reasonable choice as the Langhoff et al (1986) coefficients show relatively small errors in the comparison of populations from P-and R-branch lines, as well as those of van der Loo and Groenenboom (2007) and Brooke et al (2016). Other published sets (e.g.…”

Section: Instrumentationmentioning

confidence: 99%

Analysis of 24 years of mesopause region OH rotational temperature observations at Davis, Antarctica – Part 1: long-term trends

2020

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Abstract. The long-term trend, solar cycle response, and residual variability in 24 years of hydroxyl nightglow rotational temperatures above Davis research station, Antarctica (68∘ S, 78∘ E) are reported. Hydroxyl rotational temperatures are a layer-weighted proxy for kinetic temperatures near 87 km altitude and have been used for many decades to monitor trends in the mesopause region in response to increasing greenhouse gas emissions. Routine observations of the OH(6-2) band P-branch emission lines using a scanning spectrometer at Davis station have been made continuously over each winter season since 1995. Significant outcomes of this most recent analysis update are the following: (a) a record-low winter-average temperature of 198.3 K is obtained for 2018 (1.7 K below previous low in 2009); (b) a long-term cooling trend of -1.2±0.51 K per decade persists, coupled with a solar cycle response of 4.3±1.02 K per 100 solar flux units; and (c) we find evidence in the residual winter mean temperatures of an oscillation on a quasi-quadrennial (QQO) timescale which is investigated in detail in Part 2 of this work. Our observations and trend analyses are compared with satellite measurements from Aura/MLS version v4.2 level-2 data over the last 14 years, and we find close agreement (a best fit to temperature anomalies) with the 0.00464 hPa pressure level values. The solar cycle response (3.4±2.3 K per 100 sfu), long-term trend (-1.3±1.2 K per decade), and underlying QQO residuals in Aura/MLS are consistent with the Davis observations. Consequently, we extend the Aura/MLS trend analysis to provide a global view of solar response and long-term trend for Southern and Northern Hemisphere winter seasons at the 0.00464 hPa pressure level to compare with other observers and models.

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Section: Instrumentationmentioning

confidence: 99%

Analysis of 24 years of mesopause region OH rotational temperature observations at Davis, Antarctica – Part 1: long-term trends

2020

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“…Ground based optical measurements of the Meinel emission bands of the hydroxyl (OH) molecule produced by the exothermic hydrogen (H)ozone (O3) reaction (H + O3 -> OH * + 3.34 eV) have been used extensively over almost six decades as a method of measuring atmospheric temperature in the vicinity of the mesopause (Kvifte, 1961;Sivjee, 1992;Beig et al 2003;Beig 2006;Beig et al 2008;Beig 2011). The emission is centred about 87 km altitude and the rotational temperatures derived are representative of the kinetic temperatures, weighted by the shape and width of the layer (~8 km full-width at halfmaximum (FWHM)).…”

Section: Introductionmentioning

confidence: 99%

Analysis of 24 years of mesopause region OH rotational temperature observations at Davis, Antarctica – Part 1: Long-term trends

French¹,

Mulligan²,

Klekociuk³

2020

Preprint

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Abstract. The long term trend, solar cycle response and residual variability in 24 years of hydroxyl nightglow rotational temperatures above Davis Research Station, Antarctica (68° S, 78° E) is reported. Hydroxyl rotational temperatures are a layer-weighted proxy for kinetic temperatures near 87 km altitude and have been used for many decades to monitor trends in the mesopause region in response to increasing greenhouse gas emissions. Routine observations of the OH(6–2) band P-branch emission lines using a scanning spectrometer at Davis station have been made continuously over each winter season since 1995. Significant outcomes of this most recent analysis update are (a) a record low winter-average temperature of 198.3 K is obtained for 2018 (1.7 K below previous low in 2009) (b) a long term cooling trend of 1.2 K/decade persists, coupled with a solar cycle response of 4.3 K/100 solar flux units and (c) we find evidence in the residual winter mean temperatures of an oscillation on a quasi-quadrennial (QQO) timescale which is investigated in detail in part 2 of this work. Our observations and trend analyses are compared with satellite measurements from Aura/MLS version v4.2 level 2 data over the last 14 years and we find close agreement (a best fit) with the 0.00464 hPa pressure level values. The solar cycle response, long-term trend and underlying QQO residuals are consistent with the Davis observations. Consequently, we extend the Aura/MLS trend analysis to provide a global view of solar response and long term trend for southern and northern hemisphere winter season to compare with other observers and models.

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“…Once again, lidars (e.g., She et al, 1993) and meteor radars (e.g., Hocking and Hocking, 2002) play a key role. Spectroscopy of the OH radical (Kvifte, 1961;Sivjee and Hamwey, 1987) is another longstanding method used to sense temperatures in the mesopause.…”

Section: Introductionmentioning

confidence: 99%

Thermospheric neutral temperatures derived from charge-exchange produced N<sub>2</sub><sup>+</sup> Meinel (1,0) rotational distributions

et al. 2013

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Abstract. Thermalized rotational distributions of neutral and ionized N2 and O2 have long been used to determine neutral temperatures (Tn) during auroral conditions. In both bright E-region (≲150 km) auroras, and in higher-altitude auroras, spectral distributions of molecular emissions employed to determine Tn in the E-region cannot likewise be used to obtain Tn in the F-region. Nevertheless, charge-exchange reactions between high-altitude (≳130 km) species provide an exception to this situation. In particular, the charge-exchange reaction O+(2D) + N2(X) → N+2(A2Πu, ν' = 1 + O(3P) yields thermalized N2+ Meinel (1,0) emissions, which, albeit weak, can be used to derive neutral temperatures at altitudes of ~130 km and higher. In this work, we present N2+ Meinel (1,0) rotational temperatures and brightnesses obtained at Svalbard, Norway, during various auroral conditions. We calculate Tn at thermospheric altitudes of 130–180 km from thermalized rotational populations of N2+ Meinel (1,0); these emissions are excited by soft electron (≲1 keV) impact and charge-exchange reactions. We model the contributions of the respective excitation mechanisms, and compare derived brightnesses to observations. The agreement between the two is good. Emission heights obtained from optical data, modeling, and ISR data are consistent. Obtaining thermospheric Tn from charge-exchange excited N2+ Meinel (1,0) emissions provides an additional means of remotely sensing the neutral atmosphere, although certain limiting conditions are necessary. These include precipitation of low-energy electrons, and a non-sunlit emitting layer.

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Temperature measurements from OH bands

Cited by 25 publications

References 8 publications

Analysis of 24 years of mesopause region OH rotational temperature observations at Davis, Antarctica – Part 1: long-term trends

Analysis of 24 years of mesopause region OH rotational temperature observations at Davis, Antarctica – Part 1: long-term trends

Analysis of 24 years of mesopause region OH rotational temperature observations at Davis, Antarctica – Part 1: Long-term trends

Thermospheric neutral temperatures derived from charge-exchange produced N<sub>2</sub><sup>+</sup> Meinel (1,0) rotational distributions

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Temperature measurements from OH bands

Cited by 25 publications

References 8 publications

Analysis of 24 years of mesopause region OH rotational temperature observations at Davis, Antarctica – Part 1: long-term trends

Analysis of 24 years of mesopause region OH rotational temperature observations at Davis, Antarctica – Part 1: long-term trends

Analysis of 24 years of mesopause region OH rotational temperature observations at Davis, Antarctica – Part 1: Long-term trends

Thermospheric neutral temperatures derived from charge-exchange produced N&lt;sub&gt;2&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt; Meinel (1,0) rotational distributions

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Thermospheric neutral temperatures derived from charge-exchange produced N<sub>2</sub><sup>+</sup> Meinel (1,0) rotational distributions