Using airglow to understand the energetic balance in CO2-dominated atmospheres

Transcription

1 Using airglow to understand the energetic balance in CO2-dominated atmospheres Marie-Ève Gagné1,2, Stella M. L. Melo2, Kimberly Strong1 Department of Physics, University of Toronto, Toronto, Canada 2 Space Science & Technology, Canadian Space Agency, Montreal, Canada 1 46th CMOS Congress 2012 Montreal, Canada # 5391

2 outline motivation review of nightglow observations airglow simulations summary

3 before we start... Airglow are emissions from internal energy transitions of excited species in a planetary atmosphere Leblanc et al., JGR (2006)

4 motivation Airglow is a recognized tool to probe important characteristics of the atmosphere composition dynamics energetic budget thermal balance

5 motivation Atomic oxygen is the reconciliation factor between models and observations in the middle atmosphere Forget et al., JGR (2009)

6 motivation Atomic oxygen density has a strong effect on the CO2 15-µm cooling Forget et al., JGR (2009)

7 motivation Airglow emissions from excited O 2 can be used to derive the atomic oxygen density Zmax = peak height [O]max = peak density S = scale factor H = scale height equation from Reed and Chandra, JGR (1975) suggested to be applied to airglow profiles by Sharp & McDade, EOS Trans. AGU (1996) representability tested with airglow by Melo et al., JGR (2001)

8 motivation Gérard et al., Icarus (2009)

9 motivation Atomic oxygen density can be extracted from airglow assuming knowledge of the photochemistry Copeland and Slanger, Chem. Rev. (2003) O + O + CO2 O2* + CO2 O2* + CO2 O2 + CO2 O2* O2 + hν Herzberg II IR Atmospheric

10 motivation Atomic oxygen density can be extracted from airglow assuming knowledge of the photochemistry Banks and Kockarts (1973) N + O NO* NO* + CO2 NO + CO2 NO* NO + hν Delta Gamma

11 review of nightglow observations The Venus and Mars atmospheres have a comparable composition at the airglow layer

12 review of nightglow observations SPICAM made the first detection of nighttime airglow on Mars Bertaux et al., Science (2005)

13 review of nightglow observations VIRTIS confirmed the detection of the Herzberg II band in the Venus nightglow Garcia Munoz et al., JGR-Planets (2009)

14 review of nightglow observations VIRTIS also observed the O2 IR-atmospheric band systems Garcia Munoz et al., JGR-Planets (2009)

15 review of nightglow observations OMEGA made the first detection of O 2 nighttime airglow on Mars Gondet et al., EGU Assembly (2010)

16 review of nightglow observations CRISM on MRO also observed the O 2 IR nighttime emission around the same time Clancy et al., MAMO (2011)

17 airglow simulations - Mars We used the LMD-MGCM to provide the atmospheric background 3-D model of the Mars atmosphere horizontal resolution: vertical resolution: 50 σ-pressure levels altitude: 4 to 200 km

18 airglow simulations - Mars Herzberg II IR Atmospheric NO

19 airglow simulations - Venus We used the VTGCM to provide the atmospheric background a 3-D model of the Venus upper atmosphere horizontal resolution: 5 5 vertical resolution: 69 evenly-spaced log-pressure levels altitude: km

20 airglow simulations - Venus Herzberg II IR Atmospheric NO

21 summary We investigated the O2 Herberg II & IR Atmospheric, and the NO airglow emissions in Venus and Mars at night look into literature to determine the available sets of kinetic parameters determine the best set of parameters to simulate the Mars and Venus O2 emissions at night exploit consistency among available measurements of Venus and Mars O2 airglow improve our understanding of O2 photochemistry in a CO2-dominated atmosphere

22 thank you! Any questions? comments? suggestions? Acknowlegments: Jean-Claude Gérard, Université de Liège Francisco Gonzalez-Galindo, LMD Funding: Fonds Québécois de la Recherche sur la Nature & les Technologies (FQRNT) National Science & Engineering Research Council (NSERC) Canadian Space Agency Research Affiliate Program Centre for Global Change Science (CGCS)

23 supplementary material

24 simulations of O2 IR on Mars We use outputs from the LMD-MGCM to get Mars atmospheric conditions LS=0 lat=0 LT=00h LS=0 lat=67.5s LT=00h

25 simulations of O2 IR on Mars We use outputs from the LMD-MGCM to get Mars atmospheric conditions LS=0 lat=0 LT=00h LS=0 lat=67.5s LT=00h

26 simulations of O2 IR on Mars We use outputs from the LMD-MGCM to get Mars atmospheric conditions LS=0 lat=0 LT=00h LS=0 lat=67.5s LT=00h

27 simulations of O2 IR on Venus We use outputs from the VTGCM to get Venus atmospheric conditions LS=0 lat=0 LT=00h LS=0 lat=0 LT=00h

28 simulations of O2 IR on Venus We use outputs from the VTGCM to get Venus atmospheric conditions LS=0 lat=0 LT=00h LS=0 lat=67.5s LT=00h