A First European mission: Mars Express:
The atmospheric dataset
François FORGET
Mars Express Interdisciplinary Scientist
IPSL, LMD, CNRS, Paris, France+ the Mars Express teams !

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

Example of Mars Express Periapsis
evolution & operations

solar elevation
angle

Example of coverage: SPICAM dataset MY27 – MY 31

STAR/

LIMB , Star and Solar occultations

Phobos and the Martian Limb

HRSC Phobos and Martian limb in orbit # 3868 (10 January 2007):
Distance to Phobos 1660 km

HRSC Limb Observations•

Structure of limb haze

Orbit # 1009
Ls 108.8 (northern summer)
Local afternoon
Limb close to north pole and Korolev crater
Limb haze reaches ~19 km to 31 km altitude
Jaumann et al., 2007

Mars Express atmosphericmeasurements datasets• Temperatures & pressures• Aerosols and clouds• Seasonal Surface Frost• Water vapor• Chemical species and Ions– Ozone– O2– CO2, CO, NO, CH4, H2O2
– Electron density

Example : gravity waves in the polar night(Tellmann et al.)

2525

2020

Altitude [km]Altitude [km]DOY 233 MY 27

1515

1010135

137

139

Temperature [K]

141

143
-1.0-0.5

0.00.5Temperature Fluctuations [K](Pätzold et al. Tellmann et al.)

SPICAM stelalr occultation
Diurnal variations (N. Winter) Forget et al. 2009

DayNight

Detached aerosol layer
simultaneously in thestellar occultation
CO2condensation

Montmessin et al., Icarus
2006

Pressure retrieval using the CO2 2 µm band
Retrieval: Least-square fitting
w/ synthetic spectra fromline-by-line radiative transfer

CO2
absorption
at 2
microns

Inputs
1. Observation geometry e,i,φ2. Atmospheric state T, τ
3. Surface properties
4. Surface pressure
Features• Dust absorption / simple
scattering scheme• Multidimensional look-uptables
Forget et al. 2007

Seasonal CO2 cycle monitored byOMEGAForget et al. 2007

Surface pressure oscillations
Very flat
topography

Spiga et al. 2007

Limb images

REDGREENBLUE

Limbs in different colour images at different geographic locations

HRSC

Limb structure(h0044_0009.nd2)

SRC

7.5 km170 kmMapping	  cloud	  op-cal	  depth	  and	  par-cle	  size	  using	  Mars	  Express	  OMEGA	  imaging	  spectrometer	  data	  	  	  22	  A	  diﬃcult	  retrieval	  using	  two	  observa-ons	  with	  and	  without	  clouds	  	  (Madeleine	  et	  al.	  2011)	  23Mars	  water	  ice	  clouds	  opacity	  and	  par-cle	  size	  using	  OMEGA	  (Madeleine	  et	  al.,	  JGR	  2011)	  Processing	  clouds	  within	  the	  en@re	  dataset:	  Ongoing	  preliminary	  project:	  Mapping	  the	  clouds	  the	  OMEGA	  «	  cloud	  index	  »	  (A.	  Szantai,	  LMD)	  Processing	  and	  binning	  of	  the	  3.4	  µm	  cloud	  index	  orbite	  18	  -­‐	  8475,	  =	  7815	  ﬁles	  	  	  	  Mar@an	  Year	  26	  to	  30	  (01/2004	  -­‐	  08/2010)	  25	  Processing	  clouds	  within	  the	  en@re	  dataset:	  	  Ongoing	  preliminary	  project:	  Mapping	  the	  clouds	  using	  the	  «	  cloud	  index	  »	  (A.	  Szantai,	  LMD)	  Ls	  =60°-­‐120°	  Local	  -me	  26	  On the difficulty of measuring water vapor :comparison of Mars Express H2O measurements
Korablev et al., ISSI group

usuallyPFS LW ≤ SPICAM ≤ OMEGA ≤ TES ≤ PFS SWPFS SWOMEGASPICAMPFS LW

Ls=185
330E 60N

Fluorescence by OMEGA limb
Gondet et al. 2011

1.3 µm1.27 µm

1.12 µm

3.2 µm4.74 µmGondet et al. 2011plausible
identifications

O2 (O3) → 1.27 µm
H 2O→ 1.12 µm
H 2O→ 3.20 µm
CO / O3 → 4.74 µm+ CO2 4.3µm+ CO2 2.7µm
13CO 4.38µm
21.27
3.24.74Aymeric Spiga• Thank you