TY - JOUR
T1 - Variations in Vertical CO/CO2 Profiles in the Martian Mesosphere and Lower Thermosphere Measured by the ExoMars TGO/NOMAD
T2 - Implications of Variations in Eddy Diffusion Coefficient
AU - Yoshida, Nao
AU - Nakagawa, Hiromu
AU - Aoki, Shohei
AU - Erwin, Justin
AU - Vandaele, Ann Carine
AU - Daerden, Frank
AU - Thomas, Ian
AU - Trompet, Loïc
AU - Koyama, Shungo
AU - Terada, Naoki
AU - Neary, Lori
AU - Murata, Isao
AU - Villanueva, Geronimo
AU - Liuzzi, Giuliano
AU - Lopez-Valverde, Miguel Angel
AU - Brines, Adrian
AU - Modak, Ashimananda
AU - Kasaba, Yasumasa
AU - Ristic, Bojan
AU - Bellucci, Giancarlo
AU - López-Moreno, José Juan
AU - Patel, Manish
N1 - Funding Information:
The NOMAD experiment is led by the Royal Belgian Institute for Space Aeronomy (IASB‐BIRA), assisted by Co‐PI teams from Spain (IAA‐CSIC), Italy (INAF‐IAPS), and the United Kingdom (Open University). This project acknowledges funding by the Belgian Science Policy Office (BELSPO), with the financial and contractual coordination by the ESA Prodex Office (PEA 4000103401, 4000121493), by Spanish Ministry of Science and Innovation (MCIU) and by European funds under Grants PGC2018‐101836‐B‐I00 and ESP2017‐87143‐R (MINECO/FEDER), as well as by UK Space Agency through Grants ST/V002295/1, ST/V005332/1, and ST/S00145x/1 and Italian Space Agency through Grant 2018‐2‐HH.0. This work was supported by the Belgian Fonds de la Recherche Scientifique–FNRS under Grant No. 30442502 (ET_HOME). The IAA/CSIC team acknowledges financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award for the Instituto de Astrofísica de Andalucía (SEV‐2017‐0709). US investigators were supported by the National Aeronautics and Space Administration. Canadian investigators were supported by the Canadian Space Agency. Y. N. is supported by The international Joint Graduate Program in Earth and Environmental Sciences, Tohoku University (GP‐EES), and the Japanese Society for the Promotion of Science (JP21J13710). This work was supported by JSPS KAKENHI Grant Nos. 20H04605 and 19K03943.
Funding Information:
The NOMAD experiment is led by the Royal Belgian Institute for Space Aeronomy (IASB-BIRA), assisted by Co-PI teams from Spain (IAA-CSIC), Italy (INAF-IAPS), and the United Kingdom (Open University). This project acknowledges funding by the Belgian Science Policy Office (BELSPO), with the financial and contractual coordination by the ESA Prodex Office (PEA 4000103401, 4000121493), by Spanish Ministry of Science and Innovation (MCIU) and by European funds under Grants PGC2018-101836-B-I00 and ESP2017-87143-R (MINECO/FEDER), as well as by UK Space Agency through Grants ST/V002295/1, ST/V005332/1, and ST/S00145x/1 and Italian Space Agency through Grant 2018-2-HH.0. This work was supported by the Belgian Fonds de la Recherche Scientifique–FNRS under Grant No. 30442502 (ET_HOME). The IAA/CSIC team acknowledges financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709). US investigators were supported by the National Aeronautics and Space Administration. Canadian investigators were supported by the Canadian Space Agency. Y. N. is supported by The international Joint Graduate Program in Earth and Environmental Sciences, Tohoku University (GP-EES), and the Japanese Society for the Promotion of Science (JP21J13710). This work was supported by JSPS KAKENHI Grant Nos. 20H04605 and 19K03943.
Publisher Copyright:
© 2022. The Authors.
PY - 2022/5/28
Y1 - 2022/5/28
N2 - Using the Nadir and Occultation for MArs Discovery instrument aboard Trace Gas Orbiter, we derived the CO/CO2 profiles between 75 and 105 km altitude with the equivalent width technique. The derived CO/CO2 profiles showed significant seasonal variations in the southern hemisphere with decreases near perihelion and increases near aphelion. The estimation of the CO/CO2 profiles with a one-dimensional photochemical model shows that an altitude-dependent eddy diffusion coefficient better reproduces the observed profiles than a vertically uniform one. Our estimation suggests that the eddy diffusion coefficient in Ls = 240–270 is uniformly larger by a factor of ∼2 than that in Ls = 90–120 in the southern hemisphere, while they are comparable in the northern hemisphere. This fact demonstrates that the eddy diffusion coefficient is variable with season and latitude.
AB - Using the Nadir and Occultation for MArs Discovery instrument aboard Trace Gas Orbiter, we derived the CO/CO2 profiles between 75 and 105 km altitude with the equivalent width technique. The derived CO/CO2 profiles showed significant seasonal variations in the southern hemisphere with decreases near perihelion and increases near aphelion. The estimation of the CO/CO2 profiles with a one-dimensional photochemical model shows that an altitude-dependent eddy diffusion coefficient better reproduces the observed profiles than a vertically uniform one. Our estimation suggests that the eddy diffusion coefficient in Ls = 240–270 is uniformly larger by a factor of ∼2 than that in Ls = 90–120 in the southern hemisphere, while they are comparable in the northern hemisphere. This fact demonstrates that the eddy diffusion coefficient is variable with season and latitude.
KW - Mars
KW - atmospheric composition
KW - eddy diffusion coefficient
KW - mesosphere
KW - retrieval
KW - spectroscopy
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U2 - 10.1029/2022GL098485
DO - 10.1029/2022GL098485
M3 - Article
AN - SCOPUS:85131290263
SN - 0094-8276
VL - 49
JO - Geophysical Research Letters
JF - Geophysical Research Letters
IS - 10
M1 - e2022GL098485
ER -