First results on Martian carbon monoxide from<i>Herschel</i>/HIFI observations

Hartogh, P.; Błęcka, M. I.; Jarchow, C.; Sagawa, Hideo; Lellouch, E.; Val-Borro, M. de; Rengel, Miriam; Medvedev, Alexander S.; Swinyard, Bruce; Moreno, R.; Cavalié, T.; Lis, D. C.; Banaszkiewicz, M.; Bockelée‐Morvan, Dominique; Crovisier, J.; Encrenaz, Thérèse; Küppers, M.; Lara, L. M.; Szutowicz, S.; Vandenbussche, B.; Bensch, F.; Bergin, Edwin A.; Billebaud, F.; Biver, Nicolás; Blake, Geoffrey A.; Blommaert, J. A. D. L.; Cernicharo, J.; Decin, L.; Encrenaz, P.; Feuchtgruber, H.; Fulton, T.; Graauw, Th. de; Jehin, Emmanuël; Kidger, M.; Lorente, R.; Naylor, David; Portyankina, Ganna; Sánchez‐Portal, M.; Schieder, R.; Sidher, S.; Thomas, N.; Verdugo, E.; Waelkens, Christoffel; Lorenzani, A.; Tofani, G.; Natale, E.; Pearson, J. C.; Klein, T.; Leinz, C.; Güsten, R.; Krämer, C.

doi:10.1051/0004-6361/201015159

Cited by 20 publications

(7 citation statements)

References 28 publications

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“…The absolute value of the mixing ratio measured by SAM ranges from 400 ppm to 800 ppm during this period, which is slightly lower than the 700-1000 ppm reported by CRISM for this region on Mars. Other orbital and ground-based measurements also report greater CO mixing ratios than the in situ values (Billebaud et al, 2009;Encrenaz et al, 2006;Hartogh, Błęcka, et al, 2010;Krasnopolsky, 2003Krasnopolsky, , 2015Sindoni et al, 2011;Smith et al, 2009). There are several possible explanations for any discrepancy between the surface and the orbital and groundbased observations, including the difference in spatial sampling, the effect of any local depletions in Gale Crater, errors in the SAM CO measurement, and the distinction between a point and columnintegrated measurement.…”

Section: 1029/2019je006175mentioning

confidence: 92%

Seasonal Variations in Atmospheric Composition as Measured in Gale Crater, Mars

et al. 2019

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The Sample Analysis at Mars (SAM) instrument onboard the Mars Science Laboratory Curiosity rover measures the chemical composition of major atmospheric species (CO 2 , N 2 , 40 Ar, O 2 , and CO) through a dedicated atmospheric inlet. We report here measurements of volume mixing ratios in Gale Crater using the SAM quadrupole mass spectrometer, obtained over a period of nearly 5 years (3 Mars years) from landing. The observation period spans the northern summer of MY 31 and solar longitude (L S) of 175°through spring of MY 34, L S = 12°. This work expands upon prior reports of the mixing ratios measured by SAM QMS in the first 105 sols of the mission. The SAM QMS atmospheric measurements were taken periodically, with a cumulative coverage of four or five experiments per season on Mars. Major observations include the seasonal cycle of CO 2 , N 2 , and Ar, which lags approximately 20-40°of L S behind the pressure cycle driven by CO 2 condensation and sublimation from the winter poles. This seasonal cycle indicates that transport occurs on faster timescales than mixing. The mixing ratio of O 2 shows significant seasonal and interannual variability, suggesting an unknown atmospheric or surface process at work. The O 2 measurements are compared to several parameters, including dust optical depth and trace CH 4 measurements by Curiosity. We derive annual mean volume mixing ratios for the atmosphere in Gale Crater: CO 2 = 0.951 (±0.003), N 2 = 0.0259 (±0.0006), 40 Ar = 0.0194 (±0.0004), O 2 = 1.61 (±0.09) x 10-3 , and CO = 5.8 (±0.8) x 10-4. Plain Language Summary The atmosphere of Mars is made up of primarily carbon dioxide, and during the Martian year, the barometric pressure is known to cycle up and down substantially as this carbon dioxide freezes out and then is rereleased from polar caps. The Mars Science Laboratory Curiosity rover has now acquired atmospheric composition measurements at the ground over multiple years, capturing the variations in the major gases over several seasonal cycles for the first time. With the Sample Analysis at Mars instrument, the annual average composition in Gale Crater was measured as 95.1% carbon dioxide, 2.59% nitrogen, 1.94% argon, 0.161% oxygen, and 0.058% carbon monoxide. However, the abundances of some of these gases were observed to vary up to 40% throughout the year due to the seasonal cycle. Nitrogen and argon follow the pressure changes but with a delay, indicating that transport of the atmosphere from pole to pole occurs on faster timescales than mixing of the components. Oxygen has been observed to show significant seasonal and year-to-year variability, suggesting an unknown atmospheric or surface process at work. These data can be used to better understand how the surface and atmosphere interact as we search for signs of habitability.

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Section: 1029/2019je006175mentioning

confidence: 92%

Seasonal Variations in Atmospheric Composition as Measured in Gale Crater, Mars

et al. 2019

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“…A.1). A forward line-by-line (LBL) radiative transfer model described in Jarchow & Hartogh (1995) that was previously applied to Mars (Hartogh et al 2010b) and Venus (Rengel et al 2008) was used to calculate beamaveraged synthetic spectra in spherical geometry. The broadening due to planet rotation is negligible for this transition given the subobserver latitude, rotational axis tilt, and beam center offset (1 from the central meridian), even though it was taken into account in our simulations.…”

Section: Discussionmentioning

confidence: 99%

First detection of the 63μm atomic oxygen line in the thermosphere of Mars with GREAT/SOFIA

Rezac

Hartogh

Güsten

et al. 2015

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Context. The Stratospheric Observatory for Infrared Astronomy (SOFIA) with its 2.5 m telescope provides new science opportunities for spectroscopic observations of planetary atmospheres in the far-infrared wavelength range. Aims. This paper presents first results from the 14 May, 2014 observing campaign of the Martian atmosphere at 4.7 THz using the German REceiver for Astronomy at Terahertz frequencies (GREAT) instrument. Methods. The atomic oxygen 63 µm transition, OI, was detected in absorption against the Mars continuum, with a high signal-to-noise ratio (∼35). A beam-averaged atomic oxygen from a global circulation model was used as input to the radiative transfer simulations of the observed line area and to obtain a new estimate on the column density using a grid-search method. Results. Minimizing differences between the calculated and observed line intensities in the least-square sense yields an atomic oxygen column density of (1.1 ± 0.2) × 10 17 cm −2 . This value is about twice as low as predicted by a modern photochemical model of Mars. The radiative transfer simulations indicate that the line forms in the upper atmospheric region over a rather extended altitude region of 70-120 km. Conclusions. For the first time, a far-infrared transition of the atomic oxygen line was detected in the atmosphere of Mars. The absorption depth provides an estimate on the column density, and this measurement provides additional means to constrain the photochemical models in global circulation models and airglow studies. The lack of other means for monitoring the atomic oxygen in the Martian upper atmosphere makes future observations with the SOFIA observatory highly desirable.

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“…We computed the emerging radiance using a forward model described in Jarchow & Hartogh (1995), Jarchow (1998), and Hartogh & Jarchow (2004). This model was successfully applied to planetary spectra including those of Venus and Mars (Rengel et al 2008;Hartogh et al 2010). For Titan, the model consists of a line-by-line radiative transfer model that takes into consideration a homogeneous spherically symmetric atmosphere of Titan (grid of 127 altitude points ranging from 0 to 1500 km).…”

Section: Radiative Transfer Modelling Retrieval Of Parameters and Res...mentioning

confidence: 99%

Ground-based HCN submillimetre measurements in Titan’s atmosphere: an intercomparison with Herschel observations

Rengel

Shulyak

Hartogh

et al. 2022

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Aims. The aim of this study is to measure the vertical distribution of HCN on Titan’s stratosphere using ground-based submillimetre observations acquired quasi-simultaneously with the Herschel ones. This allows us to perform a consistency check between space and ground-based observations and to build a reference mean HCN vertical profile in Titan’s stratosphere. Methods. Using APEX and IRAM 30-m, we obtained the spectral emission of HCN (4-3) and (3-2) lines. Observations were reduced with GILDAS-CLASS. We applied a line-by-line radiative transfer code to calculate the synthetic spectra of HCN, and a retrieval algorithm based on optimal estimation to retrieve the temperature and HCN vertical distributions. We used the standard deviation-based metric to quantify the dispersion between the ground-based and Herschel HCN profiles and the mean one. Results. Our derived HCN abundance profiles are consistent with an increase from 40 ppb at ~100 km to 4 ppm at ~200 km, which is an altitude region where the HCN signatures are sensitive. We also demonstrate that the retrieved HCN distribution is sensitive to the data information and is restricted to Titan’s stratosphere. The HCN obtained from APEX data is less accurate than the one from IRAM data because of the poorer data quality, and covers a narrower altitude range. Comparisons between our results and the values from Herschel show similar abundance distributions, with maximum differences of 2.5 ppm ranging between 100 and 300 km in the vertical range. These comparisons also allow us to inter-validate both data sets and indicate reliable and consistent measurements. The inferred abundances are also consistent with the vertical distribution in previous observational studies, with the profiles from ALMA, Cassini/CIRS, and SMA (the latest ones below ~230 km). Our HCN profile is also comparable to photochemical models by Krasnopolsky (2014) and Vuitton et al. (2019) below 230 km and consistent with that of Loison et al. (2015) above 250 km. However, it appears to show large differences with respect to the estimates by Loison et al. (2015), Dobrijevic & Loison (2018), and Lora et al. (2018) below 170 km, and by Dobrijevic & Loison (2018) and Lora et al. (2018) above 400 km, although they are similar in shape. We conclude that these particular photochemical models need improvement.

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First results on Martian carbon monoxide fromHerschel/HIFI observations

Cited by 20 publications

References 28 publications

Seasonal Variations in Atmospheric Composition as Measured in Gale Crater, Mars

Seasonal Variations in Atmospheric Composition as Measured in Gale Crater, Mars

First detection of the 63μm atomic oxygen line in the thermosphere of Mars with GREAT/SOFIA

Ground-based HCN submillimetre measurements in Titan’s atmosphere: an intercomparison with Herschel observations

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