Mars Express «atmospheric sciences » Inputs for TGO…

1. Mars Express «atmospheric sciences »Inputs for TGO… François FORGET Mars Express Interdisciplinary Scientist IPSL Laboratoire de Météorologie Dynamique CNRS, Paris, France + the Mars Express teams !

2. Outline • Introduction to Mars Express • Mars meteorology • Temperatures • Surface pressure • Dust and clouds • Water vapor • Other Trace gases

3. Mars Express Orbiter • 7 main Instruments : • HRSC (camera) : visible • OMEGA (imaging Vis and NIR spectrometer) : 0.3-5.2 µm • PFS (NIR and thermal spectrometer): SWC:1.2-5.8 µm + LWC 6-50 µm • SPICAM (UV and NIR atmospheric spectrometer): 0.1-0.31 µm + 1-1.7 µm • ASPERA (Energetic Neutral Atoms Imager • MaRS: Radio Science Experiment • Marsis : Radar

4. Eccentric Orbit + Pericenter latitude drift

5. Sun elevation i < 0° 0 < i < 15° 15° < i <30° I > 30° Pericenter latitude = f(t) 10/01/04 30/05/04 •  orbit 10000 upcoming this year • - Mission extension confirmed for 2011+2012 • - and adopted for 2013+2014, pending mid-term confirmation.

6. Thermal structure in the lower atmosphere with PFS PFS TES spectral resolution 1.8 cm-1

7. Zasova et al.

8. Thermal structure below 50 km : LMD GCM prediction with Mars Express PFS (Giuranna et al. 2007) Ls = 50°-70° (N. spring) MorningEvening 60 km 40 km 20 km PFS obs GCM model 60 km 40 km 20 km

9. PFS aerosol thermal infared observations Silicate dust Water ice clouds of different kinds • polar hood • topographic clouds • equatorial cloud belt • morning haze • night fog in Hellas • clouds above the melting polar cap.

10. One Lesson from Mars Express: Meteorology data from PFS (T(z), dust, clouds) could have been shared as well as possible and as early as possible with the other instruments team to help data processing  Role of MCS on TGO

11. MaRS : radio sciences(Pätzold et al. Tellmann et al.) • uses the Radio Subsystem (High Gain Antenna) of • Mars Express • no Ultrastable Oscillator (only ingress) • But: higher sensitivity of measurement in Twoway • coherent downlink at two frequencies: X-Band (8.4 GHz) • S-Band (2.3 GHz)

12. MaRS : radio sciencesComparison with MGS (Pätzold et al. Tellmann et al.) Solar Longitude

13. Comparison with MGS Local Time (Pätzold et al. Tellmann et al.)

14. Upper atmosphere temperature with SPICAM stellar occultations (60-130 km) [Forget et al. 2009]

16. Density to Temperature profiles Spectra Slant densities CO2 density Temperature Ls = 11°, 16.8°N

17. Montmessin et al. 2011

18. Surface pressure retrievals with OMEGA at 2 µm

19. Principle of the pressure retrieval • Retrieval: Least-square fitting w/ synthetic spectra from line-by-line radiative transfer • Inputs • Observation geometry e,i,φ • Atmospheric state T, τ • Surface properties • Surface pressure • Features • Dust absorption / simple scattering scheme • Multidimensional look-up tables CO2 absorption at 2 microns Forget et al. 2007

20. Seasonal CO2 cycle monitored by OMEGA Forget et al. 2007

21. Surface pressure oscillations Very flat topography Spiga et al. 2007

22. Temperature Dust opacity Pyroxenes Instrumental noise Relative error on a given pressure measurement Forget et al. 2007

23. Total relative error: Monte-Carlo random exploration • 1-sigma relative error of • 7 Pa for A_L=0.29 • 10 Pa for A_L=0.2 • 15 Pa for A_L=0.15 OMEGA instrumental standard deviation was evaluated to 1.3 Pa Forget et al. 2007

24. Forget et al. 2007

25. Observation of aerosol at solar wavelengths • OMEGA : • Nadir : not easy by several methods (Maatanen et al. 2010, Vincendon et al. 2007,2011 : dust brighter than expected; Doute et al. 2011 use effect on CO2 2µm band at high airmass) • Limb observations: very promising, but not yet fully analysed (Fouchet et al. 2006, Vincendon et al. 2011 more soon). • SPICAM: UV : • limb observations (Rannou et al. 2006) • Stellar occultation (Montmessin et al., 2006) • Solar occultation (Listowski, 2011) • SPICAM NIR : solar occultations • Fedorova et al. (2010)

26. Dust at the south pole sun surface reflectance is 0 at λ = 2.64 µm reflectance factor CO2 ice wavelength (µm) Vincendon et al. 2007,2009

27. Spatial variations of the dust optical depth 2004 / 2005 2006 / 2007 Vincendon et al. 2009

28. Observation of aerosol at solar wavelengths • OMEGA : • Nadir : not easy by several methods (Maatanen et al. 2010, Vincendon et al. 2007,2011 : dust brighter than expected; Doute et al. 2011 use effect on CO2 2µm band at high airmass) • Limb observations: very promising, but not yet fully analysed (Fouchet et al. 2006, more soon). • SPICAM: UV : • limb observations (Rannou et al. 2006) • Stellar occultation (Montmessin et al., 2006) • Solar occultation (Listowski, 2011) • SPICAM NIR : solar occultations • Fedorova et al. (2010)

29. Fedorova et al. (2010)

30. SPICAM IR – AOTF spectrometer: Simultaneous observations of H2O, CO2 and aerosols • 1) H2O density from 1.38 mm band • 2) Atmospheric density from 1.43 mm CO2 band • 3) Aerosol extinction profiles and particle size distribution with 10 spectral points outside gaseous absorption bands H2O Aerosol points: dashed lines CO2

31. Problem with solar occultation – Pointing Cause: mis-pointing of the real optical axis wrt predicted one Solution: find the altitude shift that gives the best agreement between observed and modeled CO2 profile Method: weighted mean altitude difference of the profile NOTE: recently studied by Scanning the solar disk in two orthogonal planes with constant θ/φ coordinates wrt. spacecraft body frame <Δh> = 14.64 km etc... Maltagliatti et al.

32. Sun occultation examples of spectra • A principle of sequential scanning of a spectrum: short windows and dots • Two detectors • The record of a spectrum takes 4-6 seconds • Vertical resolution is 3.7 km with distance to limb 3000 km • A new optimal command for SPICAM IR permitting simultaneous observations of CO2, H2O and aerosol vertical distributions with spectral dependence of aerosol extinction in solar occultation mode was adapted only in April 2006 4 sec 4 sec 6 sec 4 sec • Fedorova et al. (2010)

33. Vertical distribution of reff Red line is the H2O refractive index, blue line is the ‘Marsdust’ model Northern hemisphere Reff ~0.4-0.8 mm assuming a dust Reff ~0.4-1.2 mm assuming H2O The size gradient has been observed High-altitude cloud with reff=0.1-0.3 mm Southern hemisphere • Fedorova et al. (2010)

34. Fedorova et al. (2010) Particle size variationswith season and latitude reff, mm

35. Observation of water ice clouds at solar wavelengths • SPICAM UV : Mateshvili et al. (2007) • OMEGA NIR : Madeleine et al. (2011): Mars water ice clouds opacity and particle size • LIMB observations

36. A difficult retrieval using two observations with and without clouds (Madeleine et al. 2011)

37. Mars water ice clouds opacity and particle size using OMEGA (Madeleine et al., submitted to JGR)

38. CO2 ice clouds

39. Detection of high altitude CO2 ice clouds with OMEGA (Montmessin et al. 2007) • Opacity > 0.2 • Altitude ~80 km • Reff up to 1.5 m First spectroscopic identification by Mars Express (PFS, OMEGA, Formisano et al. 2006, Montmessin et al. 2007) Observations by MOC & TES (Clancy et al. 2007), SPICAM (Montmessin et al. 2006), VMC, THEMIS (McConnochie et al.)

40. SPICAM stellar occultation Forget et al. 2009 CO2 condensation

41. Detached aerosol layer simultaneously in the stellar occultation Montmessin et al., Icarus 2006 CO2 condensation

42. Seasonal evolution map OMEGA HRSC (spicam)

43. Mars Express H2O measurements • PFS spectral resolution 1.4 cm-1 • LW 25-35 µm: processed by 2 groups: Fouchet et al., Icarus 2007 • SW 2.56 µm: processed by 3 groups: Tschimmel et al., Icarus 2008. • OMEGA 2.56 µm mapping processed by 2 groups • Encrenaz et al. A&A 2005, 2008 • Melchiorri et al. PSS 2007, Icarus 2009 • Maltagliati et al., 2008; 2009 in press? • SPICAM 1.37 µm spectral resolution 3.5 cm-1 processed by one group • Fedorova et al., JGR 2006 Compared to Mars Global Surveyor TES • TES 25-50 µm, spectral resolution 6.25 or 12.5 cm-1 Korablev et al. 2009

44. On the difficulty of measuring water vapor : comparison of Mars Express H2O measurements Korablev et al., ISSI group usually PFS LW ≤ SPICAM ≤ OMEGA ≤ TES ≤ PFS SW PFS SW OMEGA SPICAM PFS LW

45. Side effects of Mars Express water vapour comparisons Korablev et al., ISSI group • TES/MGS database modification • Bug in processing low resolution (12.5 cm-1) portion of data • Reduction of H2O content in this data by 30% • MAWD/Viking dataset modification • Reprocessing of MAWD with new spectroscopic database (HITRAN 2004) • Reduction of the entire dataset by 60%

46. Solar occultation water vapor retrieval (Maltagliatti et al. : in revision for Science)

47. Solar occultation water vapor retrieval (Maltagliatti et al. : in revision for Science) — Observation — Model fit

48. Solar occultation water vapor retrieval (Maltagliatti et al. : in revision for Science) — Observation — LMD GCM

49. Solar occultation water vapor retrieval (Maltagliatti et al. : in revision for Science)

50. Trace Gas Observations • Ozone • O2 • NO • CO • SO2 ? • H2O2 ? • Methane