CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;(ν&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;)-O quenching rate coefficient derived from coincidental SABER/TIMED and Fort Collins lidar observations of the mesosphere and lower thermosphere

Kutepov, A. A.; She, C. Y.; Smith, Anne K.; Pesnell, W. D.; Goldberg, R. A.

doi:10.5194/acp-12-9013-2012

Cited by 30 publications

(27 citation statements)

References 53 publications

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“…Remsberg et al (2008) found that the uncertainties associated with the CO 2 VMR contributed one of the largest sources of systematic error in the non-LTE region, with uncertainty values of 1. Feofilov et al, 2012;Panka et al, 2017), and the uncertainties associated with CO 2 (ν 2 ) vibrational quanta exchange rate constant (k vv ). García-Comas et al (2008) demonstrated that the non-LTE region T k (z) errors vary with both latitude and season and were largest during the polar summer (compared to a midlatitude summer location).…”

Section: 1029/2018jd028742mentioning

confidence: 99%

Validation of SABER v2.0 Operational Temperature Data With Ground‐Based Lidars in the Mesosphere‐Lower Thermosphere Region (75–105 km)

et al. 2018

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The National Aeronautics and Space Administration (NASA) Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) Sounding of the Atmosphere using Broadband Radiometry (SABER) instrument performs near‐global measurements of the vertical kinetic temperature (Tk) profiles and volume mixing ratios of various trace species (including O3, CO2, and H2O), with data available from 2002 to present. In this work, the first comparative study of the latest publically available SABER version 2.0 operational retrieval is reported in order to assess the performance of satellite Tk profiles relative to high‐resolution ground‐based lidar profiles. Collocated multiyear seasonal average Tk profiles were compared at nine different locations, representing a variety of different latitudes. In general, the SABER v2.0 and lidar mean seasonal Tk profiles agree well, with the smallest absolute values of ΔTk (z) (SABER minus lidar) found between 85 and 95 km, where the respective SABER and lidar uncertainties were smallest. At altitudes ≥100 km, the SABER Tk (z) typically exhibited warmer temperatures relative to the lidar Tk (z) profiles, whereas for altitudes ≤85 km, SABER Tk (z) was cooler. Relative to lidar, SABER tends to exhibit a warm bias during high‐latitude summertime, with the reasons for this currently still unclear. Overall, SABER was able to reproduce the general latitude‐ and season‐specific variations in the lidar Tk profiles and shown to be statistically similar for most seasons, at most locations, for the majority of altitudes, and with no overall bias.

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Section: 1029/2018jd028742mentioning

confidence: 99%

Validation of SABER v2.0 Operational Temperature Data With Ground‐Based Lidars in the Mesosphere‐Lower Thermosphere Region (75–105 km)

et al. 2018

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“…Since only 2.4 % of the N 2 molecules participate in the RV energy transfer process, the rate coefficient for deactivation of CO 2 (v 2 ) by N 2 would be k VT (N 2 ) = ((2.32 ± 1.1) × 0.024) × 10 −12 = (5.6 ± 2.6) × 10 −14 . A larger calculated rate coefficient k N 2 would not be a problem, since the v 2 mode of CO 2 at least up to 90 km altitude is in local thermodynamic equilibrium (LTE); i.e., its vibrational temperature is nearly the same as the translational temperature (Feofilov et al, 2012;Stair et al, 1985). Tables 1a-d, using the atmospheres, provided by Feofilov and López-Puertas, give the rate coefficients k VT (N 2 ), the fifth column, and k VR (N 2 ), the last column, required by k x given by these atmospheres.…”

Section: Thermal Rotational Levelsmentioning

confidence: 99%

“…Later analyses of space-based observations have given values around 6×10 −12 (cm 3 s −1 ) Ratkowski et al, 1994;Gusev et al, 2006;Feofilov et al, 2012, and references therein), except for the Vollmann and Grossmann (1997) study giving a value of 1.5 × 10 −12 (cm 3 s −1 ). The study of Feofilov et al (2012) determined the rate coefficient by coincidental SABER/TIMED and Fort Collins sodium lidar observations in the MLT region and arrived at values of (5.5 ± 1.1) × 10 −12 cm 3 s −1 at 90 km altitude and (7.9 ± 1.2) × 10 −12 cm 3 s −1 at 105 km, with an average value of (k ATM = 6.5 ± 1.5) × 10 −12 cm 3 s −1 . The study of "suggests a value of between 3 and 6 × 10 −12 cm 3 s −1 at 300 K" and temperature "independent or negative temperature dependence".…”

Section: Introductionmentioning

confidence: 99%

“…Using the average of the value of k ATM 3 and 6 × 10 −12 cm 3 s −1 , 4.5 × 10 −12 cm 3 s −1 , suggested by , and k LAB = 2.5×10 −12 cm 3 s −1 , we get k x = 2.0 × 10 −12 cm 3 s −1 , a smaller value independent of temperature (altitude). It should be noted that the contribution to the rate coefficient k ATM by unknown mechanism k x nearly equals or is greater (Feofilov et al, 2012) than k LAB , the contribution by the major constituent atomic oxygen. As pointed out by Feofilov (2014), the GCM (general circulation models) use of a value of k GCM = 3.0 × 10 −12 cm 3 s −1 for this rate coefficient (Bougher et al, 1999) further complicates the problem.…”

Section: Introductionmentioning

confidence: 99%

“…To resolve the discrepancy between k ATM and k LAB , Feofilov et al (2012) postulate that nonthermal, or "hot", oxygen atoms, produced in the MLT region by photolysis of O 2 and dissociative recombination of O + 2 , etc., may serve as an additional source of CO 2 (v 2 ) level excitation. These authors have derived CO 2 volume mixing ratio (VMR) parts per million by volume (ppmv) in the MLT region for the time of their experiment from atmospheric models as well as space-based observations.…”

Section: Introductionmentioning

confidence: 99%

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Technical Note: On the possibly missing mechanism of 15 μm emission in the mesosphere–lower thermosphere (MLT)

Sharma

2015

Atmos. Chem. Phys.

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Abstract. Accurate knowledge of the rate as well as the mechanism of excitation of the bending mode of CO 2 is necessary for reliable modeling of the mesosphere-lower thermosphere (MLT) region of the atmosphere. Assuming the excitation mechanism to be thermal collisions with atomic oxygen, the rate coefficient derived from the observed 15 µm emission by space-based experiments (k ATM = 6.0 × 10 −12 cm 3 s −1 ) differs from the laboratory measurements (k LAB = (1.5−2.5)×10−12 cm 3 s −1 ) by a factor of 2-4. The general circulation models (GCMs) of Earth, Venus, and Mars have chosen to use a median value of k GCM = 3.0 × 10 −12 cm 3 s −1 for this rate coefficient. As a first step to resolve the discrepancies between the three rate coefficients, we attempt to find the source of disagreement between the first two. It is pointed out that a large magnitude of the difference between these two rate coefficients (k x ≡ k ATM − k LAB ) requires that the unknown mechanism involve one or both major species: N 2 , O. Because of the rapidly decreasing volume mixing ratio (VMR) of CO 2 with altitude, the exciting partner must be long lived and transfer energy efficiently. It is shown that thermal collisions with N 2 , mediated by a near-resonant rotation-to-vibration (RV) energy transfer process, while giving a reasonable rate coefficient k VR for deexcitation of the bending mode of CO 2 , lead to vibration-totranslation k VT rate coefficients in the terrestrial atmosphere that are 1-2 orders of magnitude larger than those observed in the laboratory. It is pointed out that the efficient nearresonant rotation-to-vibration (RV) energy transfer process has a chance of being the unknown mechanism if very high rotational levels of N 2 , produced by the reaction of N and NO and other collisional processes, have a super-thermal population and are long lived. Since atomic oxygen plays a critical role in the mechanisms discussed here, it suggested that its density be determined experimentally by ground-and spacebased Raman lidars proposed earlier.

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Temperature trends in the midlatitude summer mesosphere

2013

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Here we analyze the contribution of varying concentrations of CO 2 and O 3 to the temperature trend in the mesosphere. It is important to distinguish between trends on pressure altitudes, z p , and geometrical altitudes, z geo , where the latter includes the effect of shrinking due to cooling at lower heights. For the period 1961-2009, temperature trends on geometrical and pressure altitudes can differ by as much as -0.9 K/dec in the mesosphere. Temperature trends reach approximately -1.3˙0.11 K/dec at z p 60 km and -1.8˙0.18 K/dec at z geo 70 km, respectively. CO 2 is the main driver of these trends in the mesosphere, whereas O 3 contributes approximately one third, both on geometrical and pressure heights. Depending on the time period chosen, linear temperature trends can vary substantially. Altitudes of pressure levels in the mesosphere decrease by up to several hundred meters. We have performed long-term runs with LIMA applying twentieth century reanalysis dating back to 1871. Again, trends are nonuniform with time. Since the late nineteenth century, temperatures in the mesosphere have dropped by approximately 5-7 K on pressure altitudes and up to 10-12 K on geometrical altitudes.

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CO<sub>2</sub>(ν<sub>2</sub>)-O quenching rate coefficient derived from coincidental SABER/TIMED and Fort Collins lidar observations of the mesosphere and lower thermosphere

Cited by 30 publications

References 53 publications

Validation of SABER v2.0 Operational Temperature Data With Ground‐Based Lidars in the Mesosphere‐Lower Thermosphere Region (75–105 km)

Validation of SABER v2.0 Operational Temperature Data With Ground‐Based Lidars in the Mesosphere‐Lower Thermosphere Region (75–105 km)

Technical Note: On the possibly missing mechanism of 15 μm emission in the mesosphere–lower thermosphere (MLT)

Temperature trends in the midlatitude summer mesosphere

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