mars express «atmospheric sciences » inputs for tgo… françois forget mars express...

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 !

Outline

• Introduction to Mars Express

• Mars meteorology– Temperatures– Surface pressure– Dust and clouds

• Water vapor

• Other Trace gases

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

Eccentric Orbit + Pericenter latitude drift

Pericenter latitude = f(t)

10/01/04

30/05/04

Sun elevation

i < 0°

0 < i < 15°

15° < i <30°

I > 30°

orbit 10000 upcoming this year- Mission extension confirmed for 2011+2012 - and adopted for 2013+2014, pending mid-term confirmation.

Thermal structure in the lower atmosphere with PFS

spectral resolution 1.8 cm-1

PFS

TES

Zasova et al.

PFS obs

GCM model

Morning Evening

Thermal structure below 50 km : LMD GCM prediction with Mars Express PFS (Giuranna et al. 2007)

60 km

40 km

20 km

60 km

40 km

20 km

Ls = 50°-70° (N. spring)

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.

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

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)

MaRS : radio sciencesComparison with MGS

0 90 180 270 360

Solar Longitude [deg]

-90

-60

-30

0

30

60

90L

atit

ud

e [d

eg

]MaRSMGSOCC 10

Solar Longitude (Pätzold et al. Tellmann et al.)

Comparison with MGS

0 6 12 18 24

Local Time [hours]

-90

-60

-30

0

30

60

90

La

titu

de

[d

eg

]

MaRSMGSOCC 10

Local TimeLocal Time

(Pätzold et al. Tellmann et al.)

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

Density to Temperature profiles

CO2 density Temperature

Ls = 11°, 16.8°N

Spectra

Slant densities

Montmessin et al. 2011

Surface pressure retrievals with OMEGA at 2 µm

Principle of the pressure retrieval

CO2 absorption

at 2 microns

Retrieval: Least-square fitting w/ synthetic spectra from line-by-line radiative transfer

Inputs 1. Observation geometry e,i,φ2. Atmospheric state T, τ3. Surface properties 4. Surface pressure

Features• Dust absorption / simple

scattering scheme• Multidimensional look-up

tables

Forget et al. 2007

Seasonal CO2 cycle monitored by OMEGA

Forget et al. 2007

Surface pressure oscillations

Very flat topography

Spiga et al. 2007

Relative error on a given pressure measurement

–Temperature–Dust opacity–Pyroxenes

–Instrumental noise

Forget et al. 2007

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

Forget et al. 2007

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)

27

surface reflectance is 0

at λ = 2.64 µm

refle

ctan

ce f

acto

r

CO2 ice

wavelength (µm)

sun

Dust at the south pole

Vincendon et al. 2007,2009

282004 / 2005 2006 / 2007

Spatial variations of the dust optical depth

Vincendon et al. 2009

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)

Fedorova et al. (2010)

Simultaneous observations of H2O, CO2 and aerosols

• 1) H2O density from 1.38 m band• 2) Atmospheric density from 1.43 m CO2

band • 3) Aerosol extinction profiles and particle

size distribution with 10 spectral points outside gaseous absorption bands

CO2

H2O

Spectral range: 1-1.7 µm

Spectral power:Spectral resolution

R~20000.5-1.2 nm

FOV nadir occultation

1° ~0.07° (3.5 km at 3000 km to limb)

Aerosol points: dashed lines

SPICAM IR – AOTF spectrometer:

Cause: mis-pointing of the real optical axis wrt predicted oneSolution: find the altitude shift that gives the best agreement between observed and modeled CO2 profileMethod: 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

etc...

<Δh> = 14.64 km

Problem with solar occultation – Pointing

Maltagliatti et al.

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 sec4 sec

6 sec

4 sec

Fedorova et al. (2010)

Vertical distribution of reffRed line is the H2O refractive index, blue line is the ‘Marsdust’ model

High-altitude cloud with reff=0.1-0.3 m

Northern hemisphere

Reff ~0.4-0.8 m assuming a dust

Reff ~0.4-1.2 m assuming H2O

The size gradient has been observed

Southern hemisphere

Fedorova et al. (2010)

Particle size variationswith season and latitude

reff, m

Fedorova et al. (2010)

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

37

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

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

• CO2 ice clouds

Detection of high altitude CO2 ice clouds with OMEGA (Montmessin et al. 2007)

Opacity > 0.2Altitude ~80 km

Reff up to 1.5 m

First spectroscopic identification by Mars First spectroscopic identification by Mars Express (PFS, OMEGA, Formisano et al. 2006, Express (PFS, OMEGA, Formisano et al. 2006, Montmessin et al. 2007)Montmessin et al. 2007) Observations by MOC & TES (Clancy et al. Observations by MOC & TES (Clancy et al. 2007), SPICAM (Montmessin et al. 2006), VMC, 2007), SPICAM (Montmessin et al. 2006), VMC, THEMIS (McConnochie et al.)THEMIS (McConnochie et al.)

CO2condensation

SPICAM stellar occultationForget et al. 2009

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

condensation

Seasonal evolution mapSeasonal evolution map

HRSC

OMEGA

(spicam)

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

On the difficulty of measuring water vapor : comparison of Mars Express H2O measurements

SPICAM

PFS LW

OMEGA

PFS SW

Korablev et al., ISSI group

usuallyPFS LW ≤ SPICAM ≤ OMEGA ≤ TES ≤ PFS SW

Side effects of Mars Express water vapour comparisons

• 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%

Korablev et al., ISSI group

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

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

— Observation— Model fit

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

— Observation

— LMD GCM

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

Trace Gas Observations

– Ozone– O2 – NO– CO– SO2 ?– H2O2 ?– Methane

Trace Gas Observations

– Ozone• Spicam NADIR• Spicam stellar occultation

Typical duration of obs. 30 min

Frequency of records 1 spectrum/sec

Integration time 450 ms

Field of view at pericenter ~ 2 km

CO2 O3 dustcloudssurface

SPICAMobservations in nadir mode110-320 nm Ozone

Mapping with Spicam

SPICAM raw spectra SPICAM geometrylon(t), lat(t), HL(t), Ls, SZA(t), (t)(t)

Mars Climate Databasesurface pressure, T profile, O3 profile

Radiative Transfer Model

SHDOM210-300 nm0-60 km 12 layers

Optimal Parameters• ozone column• albedo at 210 nm• albedo at 300 nm• dust opacity

Correction of dark current and stray light

Averaging over 50 s(250 spectra)

Division by Data Reference Spectrum

Olympus Mons Ls =170° (Orbit 1448)

Spectral smoothing(5 nm)

Levenberg-Marquardt fit4 free parameters: • ozone column• albedo at 210 nm• albedo at 300 nm• dust opacity

262A01Ls = 13.3

lat = 35°

lat = 70°

lat = 50°

lat = 60°

SPICAM Ozone Column

polar night

polar night

spring

spring

summer

summer

autumn

autumn

winter

winter

Perrier et al., J. Geophys. Res., 2006

Analysis of SPICAM ozone columns with the LMD GCM

GCM ozone column (micron-atmosphere)

Lefèvre et al., Nature, 2008

70N-90N

50N-70N

winter

wintersummer

summer

Model Ozone column

wintersummer

O3 profile using SPICAM UV stellar occultation(Lebonnois et al. 2007)Comparison with GCM

Trace Gas Observations

– O2 • O2 florescence (1.27µm) resulting from dayside:

– OMEGA nadir and Limb : Altieri et al. 2009;

– SPICAM NIR Nadir and Limb Guslyakova et al. 2011;

– PFS Geminale et al. 2011

• O2 Recombination Nightglow Emission at 1.27 µm – OMEGA/MEX: Bertaux et al. 2011

– SPICAM Guslyakova et al. 2011 )

Gravity waves on polar regionsas observed by OMEGA with O2 emission

Southern late winter/early spring MY28

Northern late winter MY26

Apparent MR

Apparent MR

Altieri et al. 2009

Altieri et al. 2009

Carbon Monoxide

• OMEGA (resolution Encrenaz et al. (2006) – CO main line :(2–0) at 2.35 µm

• PFS

– CO main line :(2–0) band centered at 4255 cm−1 (around 2.35 μm) difficult to use because of affected by mechanical vibrations

– Billebaud et al. (2009) Billebaud et al. 4.7 μm spectra of Mars ((1–0) ro-vibrationnal)

– Sindoni et al. PSS 2011: Measuring CO at 4235cm1 (2.36 µm) branch of (2–0) band

CO mixing ratio Sindoni et al. PSS 20114235cm1 (2.36 µm)

CO enrichment in Hellas: predicted by GCM, detected by OMEGA (Encrenaz et al. 2006)

CO main line :(2–0) at 2.35 µm

GCM : % of non condensible gaz

OMEGA observations:

HELLAS

HELLAS

Trace Gas Observations

– Ozone– O2 – CO– NO– SO2 : search in the UV with SPICAM UV nadir

observations (Marcq et al. 2011)– H2O2 : search in the thermal IR using PFS with line

at 362 cm-1 (+ 379, 416 and 433 cm-1). So far inconsistent results (Kasaba, Aoki et al. 2010)

– Methane

Methane (PFS: 3018 cm-1)• Very difficult detection by Formisano et al. (Science 2004)

• Further results by the PFS team published recently – A. Geminale, V. Formisano, M. Giuranna. Methane in Martian

atmosphere: Average spatial, diurnal,and seasonal behaviour Planetary and Space Science 56 1194–1203(2008)

– Geminale, Sindony, Formisano: Mapping methane in Martian atmosphere with PFS-MEX data Planetary and Space Science 59 137–148 (2011)

Enigmatic variability,

patchy behaviour

Geminale et al. 2008

Geminale et al. 2011

• Thank you