Mars Global Climate Model (GCM)
F. Forget, E. Millour, T. Navarro, A. Pottier, L. Montabone, A. Spiga, A. Colaitis,J.-B. Madeleine, T. Bertrand, M. Vals LMD, France
F. Lefèvre, J.-Y. Chaufray, F. Montmessin, LATMOS, France
F. Gonzalez-Galindo, M.-A. Lopez-Valverde, IAA, Spain
S. Lewis, Open University, P. Read, AOPP, UK
and the MCD/GCM teamThe LMD Mars Global Climate Model• 1st version developped in the early 1990s (Hourdin et al.
1993) Reference publication Forget et al. (1999)• Now applied to all aspect of Mars atmospheric Sciences:
Toward a “Mars System Model”

The LMD/IPSL « Mars system simulator »AtmosphericDynamics

ExosphereAtm. Escape(Latmos, LMD)

CO2 Cycle(LMD, Latmos
IDES)

Mars
GCM
Dust cycle(Oxford U., LMD,
LISA, Latmos)

Thermosphere
Ionosphere(Latmos, IAA)

« Mars Climate database »• Reference tool for the
Scientific and Space Engineercommunity• Version « pro » on DVDROM ordered par ~250 teams
from ~20 countries• Interactive website

Climate variations& paleoclimates(LMD, Brown U, IDES.)

Volcanic eruption
simulations(with Brown University)(IAA, LMD,Latmos)-Mesoscale
Model / LES(LMD)

PhotoChemistry

Water Cycle

Radon Cycle

HDO cycle(Latmos, Lesia)(LMD, Latmos)

Ancient Mars(- 3 à -4 Gyr(avec Harvard UniversityObs. Royal de Belgique)(IAA=Institut d’Astrophysique d’Andalousie)

The LMD Mars Global Climate Model• 1st version developped in the early 1990s (Hourdin et al.
1993) Reference publication Forget et al. (1999)• Now applied to all aspect of Mars atmospheric Sciences:
Toward a “Mars System Model”• The GCM is constantly improved.
•The current version is the outcome of 8 years of intensedevelopment to renew the model…
• Validation with several datasets
Used to produce a new Mars Climate Database
version 5 (see talk on Thursday by Ehouarn Millour)

Basic characteristics of the Mars Global Climate Model :2) Radiative transfer:•

TIR CO2 wide band model (Hourdin1991) + NLTE model (Lopez-Valverde2011)•NIR CO2 (NLTE)•EUV absorption•
Aerosols: Toon et al. 1989

1) LMDZ final DynamicalCore (Grid point Model)

3) Subgrid scale dynamics• Turbulence: Mellor and Yamada

6) Dust transport anddistribution : see below

2.5 Scheme••

Convection : see below
Gravity waves (orographic) +low level drag: Prametrisationof impact on the main flow4) Surface and subsurface
thermal balance5) Volatile:• CO2 cycle: see below• H2 O cycle: see below

Forget and Lebonnois (2013) In“ComparativeClimatology of Terrestrial

Improved Dynamics, Convection and Turbulence Model- New convective thermal
models to replace “simplistic”
convective adjustment.
 Subgrid scale gustiness- Improved thermal drag coef.
(Colaitis et al. 2012)

Mixed layer

Surface layer

New Roughness
Length “z0” Map
derivedfrom Extended
Martian RockAbundance Data
(Hebrard et al. 2011)

(mosaic of the CO2 ice seasonal northern polar cap) in springImproved CO2 cycle

CO2 ice varying albedo

Noncondensable
gaz depletion

Storage of heat in
subsurface water ice

Non condensable
gaz enrichment andinduced convectionSurfacecondensationof CO2Near Surface
enrichment ofother gases

Argon enhancement observed by Mars Oddyssey GRS

Sprague et al. Granada 2006

Computation In a discretizedworld (GCM)• In « hyprid coordinate » σ N+1/2
σ = p/ps → p each model layer isdefine by its boundary
σ l+1/2
σ l-1/2

σ l+1/2
σ l-1/2

Nl+1ll-1

σ1/2 = 11

4Surfacecondensationof CO2
Near Surface
enrichment ofother gases

32

1Mixing and convection induced by
non-condensible gas enrichment• CO2 : m = 44.0E-3 kg mol-1• Non-condensible gas (N2, Ar) are lighter: m = 32.37E-3 kg mol -1 (Hess, 1979)• Induce convection near the surface !
• Density changes ( ρ=Pm/(8.314 T) ) :Δm gradient equivalent to a temperature gradient
ΔT = m/T Δm

Argon column averaged mixing ratio (%)

Observation of COby CRISM (ppm)(Mike Smith 2008)

Observations

Model

Dust observed by India
Mars Orbiter Mangalyaan
mission (seen from analtitude of 8449 km)

DUST SCENARIOS
Zonal mean ofreconstructed column dust
opacities for martian year
24-31

Montabone et al. 2015
(Icarus)Improved “dust model” to simulate
observed Martian years (MY24 – MY31)
Multisize

Transport of dust
mixing ratio and dust
distribution(2 moment scheme)

Dust devil

Multisize
Constant global lifting(Madeleine et al. 2011)

Transported dust mixing ratio and size distribution (2 moment scheme)

Effective
Radius(µm)

Madeleine et al. 2011

Transported dust mixing ratio and size distribution (2 moment scheme)

Madeleine et al. 2011

Transported dust mixing ratio and size distribution (2 moment scheme)

Madeleine et al. 2011

Transported dust mixing ratio and size distribution (2 moment scheme)

Madeleine et al. 2011

NORTHERN SUMMER

Solar Flux

Sublimation

Transport

CloudsCondensation

Modelling water cycle and clouds

EARLY GCMSSIMULATION ofMars water cycle:
1) water vapor
OBSERVATION(TES, Smith 2007)

MODEL(LMD GCM)

Montmessin et al. 2004, Forget 2008

Did these « simple » GCM simulations
explain the entire water cycle ?
No ! :• Unrealistic temperatures => one must take into
account the radiative effect of water ice clouds• Unrealistic water vapor vertical distribution(e.g. Fouchet et al. 2007; Maltagliatti et al. 2012) Need for improved cloud microphysic

Water cycle and clouds
Step#1 :IR and solar
walength radiative
effects of clouds

Madeleine et al. (2011)

Radiatively active Water ice clouds in a GCM
Temperatures

Water vapor

Destabilizingfeedback

Water ice clouds

Illustration off the difficulties ; fromThomas Navarro

Water vapor seasonal cycle(Martian Year 26)

MGS/TES
Observations

GCM simulations
without microphysics

Solar Longitude Ls (°)

Alizee pottierImproving water cycle andclouds

Step#1 :IR and solar
walength radiative
effects of clouds

Step # 2: Improved cloud
Microphysics(nucleation, growth, dust
scavenging )Water vapor seasonal cycle(Martian Year 26)

MGS/TES
Observations

GCM simulationswithout microphysics

GCM simulations
with microphysics
Figure by Alizee Pottier

Water vapor profiles withimproved microphysics:
comparison with SPICAM
solar occultation data

ModelObservations

High resolution (1°x1°) water cycle sims
(Pottier et al. 2015)

Water ice clouds Ls=90°38Comparison with Mars Climate Sounder• Comparison with Binned Mars Climate Sounderdata (Luca Montabone)• Bin sizes: Ls: 5° lat: 3° lon 7.5°
• Today : Martian Year 29

Zonal mean temperatures½ (Tday + Tnight)Figure from Alizee PottierCLocal Nightime
dust at 10°N0°E

MCS observations

LMD GCM ModelDust detached layers
observed by India Mars
Orbiter Mangalyaan
mission (seen from analtitude of 8449 km)

Detached dust layer necessary to explain MCS observed thermal structure
Dust distribution predicted by the GCM

Reconstructing
the dust fieldfrom MCS
temperatureobservations
with anensemble ofGCM simulations
Ls=310 to Ls=320
MY29.

Dust distribution deduced from MCS Temperatures(LETKF data
assimilation
scheme)(Navarro et al.
2014)
LatitudeWhat is the process forming detacheddust layers ?
Dust density scaled opacity (m2 kg-1)

1) Dustenrichment
below dust
scavenging
clouds(Navarro et al.
2014)Modelling dust scavenging by ice in LMD GCM

No scavenging

Navarro et al. 2014; Bertrand et al. 2014

(Navarro et al. 2014)

Scavenging

What is the process forming detacheddust layers ?
Dust density scaled opacity (m2 kg-1)

1) Dustenrichment
below dust
scavenging
clouds(Navarro et al.
2014)2) Direct transport of dust from the boundary layer
to the mid atmosphere by “rocket dust storms” (Spigaet al. 2013) & Local topography circulation

Rocket dust storm : evolution of a local dust storm as
simulated by the LMD Mesoscale Model
Spiga et al. 2013. Model Resolution = 7 km

Relation taux de chauffage – Vitesseverticale113

Relation taux de chauffage – Vitesseverticale114

Relation taux de chauffage – Vitesseverticale

115

Relation taux de chauffage – Vitesseverticale116

Relation taux de chauffage – Vitesseverticale117

Relation taux de chauffage – Vitesseverticale118

Parameterizing rocket dust storm in LMD Global
Climate Model (GCM)

Altitude

STORM
ENVIRONMENT
X

1- Injection of dust
(detection of a dust storm)

1-X

GCM column

2- Radiative transfer in the part of the meshwith and without the storm

Altitude

STORM
1- Injection of dust
(creation of a dust storm)

ENVIRONMENTGCM column

2- Radiative transfer in the part of the meshwith and without the storm

3- Vertical transportof dust in the storm

Altitude

STORM
1- Injection of dust
(creation of a dust storm)

ENVIRONMENTGCM column

2- Radiative transfer in the part of the meshwith and without the storm

4- Detrainment of dust
from the storm to theenvironment

Altitude

WSTORM
1- Injection of dust
(creation of a dust storm)

3- Vertical transport ofdust in the storm

ENVIRONMENTGCM column

Evolution of the Martian Climate

Old terrains:
early Mars wasdifferent

-4.5

-4.0

,

Cold, icy Mars: Glacier, polar caps

-3.0
Age (Gyr)

-2.0

-1.0

Present

Variations of Obliquity on Mars

Laskar and Robutel (1993), Touma and Wisdom (1993), Laskar (2004)

Variations of Obliquity on Mars
Ice age on the Earth:
15,000 years ago

Ice ages on Mars !
Laskar and Robutel (1993), Touma and Wisdom (1993), Laskar (2004)

Ice accumulation rate (mm/yr)
high resolution simulation (2°x2°)
Obliquity = 45° , Excentricity = 0, Dust Opacity =0.2
Forget et al. Science 311, p368, 2006

mm/yr

The formation of glacier : Ice
accumulation rate (mm/yr) in a newvery high resolution simulation
Forget et al. 2006: Obliquity = 45° , Excentricity = 0, Dust Opacity =0.2

•Fan shaped deposits, drop
moraines characteristic ofcold based glaciers.
•Rock glaciers
Lucchitta 1981, Head et al. 2003,
Shean et al. 2005, 2007, Head et al.
2005, Kadish et al. 2008, Schonand Head 2012

The climates of planet Mars controlled by achaotic obliquity

Forget et al. 2008

Modelling Mars watercycle with the LMD Mars
Global Climate Model
Forget et al. 1999, ontmessin et al. 2004, Forget et al. 2008
Madeleine et al. 2012, Navarro et al. 2014

Radiative effects ofcloudLMD GCM(with radiatively active clouds)

Present day Mars
(obliquity = 25.2°)

Same Mars but withobliquity = 35°

Radiatively active clouds warm the atmosphere Much more intense water cycle (more water vapor) More clouds (positive feedback) More precipitations !
Obliquity = 35° N polar cap

Passive Clouds

Radiatively Active clouds

Cloud ice mole mixing ratio (ppm)
Temperature (K)Madeleine et al. GRL 2014

Radiatively active clouds simulations, obliquity = 35°, excentricity =0.1
Low snow albedo = 0.4, but dust storm during summer

Madeleine et al. GRL 2014

Evolution of the Martian Climate

Old terrains:
early Mars wasdifferent

-4.5

-4.0

,

Cold, icy Mars: Glacier, polar caps

-3.0
Age (Gyr)

-2.0

-1.0

PresentMARS : Warrego Vallis
150 kmEARTH(Yemen ; same scale)

Curiosity, Gale Crater, 07/2014

A 3D Global Climate Model(GCM) for early Mars
• LMDZ grid point dynamicalcore,o 64x48 or 32x32 grid points
o 15 layers• New radiative transfer core:o Correlated-k for thegaseous absorptiono Toon et al. (1989) twostream method for theaerosols• Simple parametrisation of
CO2 cloud microphysics :condensation, nucleation,transport, sedimentation(fixed CCN distribution, butvariable mean cloud particle
sizes)

Zonal mean CO2 ice density(10−6kg m−3) Ps=2 bar

Mean Surface Temperatures (K)Global mean surface temperature (K)We explored the sensitivity to• obliquity and orbit parameters• Cloud microphysicalproperties (concentration ofNuclei, supersaturation)• Presence of atmospheric dust
• surface thermal properties• Water …

Obliquity = 25°[ CCN] = 105 kg-1

Mean Surface Pressure (Bar)
Forget et al. 2012, Wordswoth et al. 2013, Kerber et al. 2015

Influence of pressure on surface
temperature evolution with topography

Forget et al. 2013

The Icy Highland
Scenario
Map of Modeled
Annual snow ice
accumulation
P=0.6 bar, ob=41.8°(Wordsworth et al. 2015)

Valley Network
drainage density(Hynek et al.,2010)