Mesoscale and microscale modeling for Mars
(and a bit of Venus)
A. Spiga
and many co-authors

Franco-japanese workshop on modeling planetary atmospheres
May 12, 2015

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 1

Outline
1

Methodology

2

Katabatic flows

3

Gravity waves

4

Deep convection

5

Boundary layer (“shallow”) convection

6

Water-ice clouds

7

Venus cloud layer

8

Conclusion
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 2

Outline
1

Methodology

2

Katabatic flows

3

Gravity waves

4

Deep convection

5

Boundary layer (“shallow”) convection

6

Water-ice clouds

7

Venus cloud layer

8

Conclusion
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 3

The Martian mesoscale “zoo”[MGS/MOC imagery, Malin Space Science Systems, 02/2002]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 4

Processes left unresolved at GCM resolutions
GCM grid
Gravity waves
Dusty deep
convection

DustdevilsTurbulent
plumesKatabatic& anabaticflow~ 500 km
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 5

Scales and Models[Spiga and Lewis, Mars Journal 2010]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 6

Mars Global Climate Model: LMD-MGCM
LMDz dynamical core
integration of conservation laws for
momentum, mass, energy, tracers

Grid spacing ∼ 200 km

LMD Mars physics
radiative transfer (dust and CO2 ), soilmodel, vertical mixing, microphysics (H2 O
and CO2 ), lifting/sedimentation, chemistry

MGS

datasettopography, thermal inertia, albedo
dust scenario

A. Spiga et al.

(LMD / UPMC)[Forget et al., JGR 1999]

Mesoscale and microscale modeling

Slide 7

Mars Mesoscale Model: LMD-MMM
WRF dynamical core

Grid spacing ∼ 10 − 1 km

integration of conservation laws for
momentum, mass, energy, tracers

LMD Mars physics
radiative transfer (dust and CO2 ), soilmodel, vertical mixing, microphysics (H2 O
and CO2 ), lifting/sedimentation, chemistry

LMD Mars GCM fields
initial and boundary conditions

MGS hi-res dataset
topography, thermal inertia, albedo
dust scenario

A. Spiga et al.

(LMD / UPMC)[Spiga and Forget, JGR 2009]

Mesoscale and microscale modeling

Slide 8Mars Large-Eddy Simulations: LMD-LES
WRF dynamical core
integration of conservation laws for
momentum, mass, energy, tracers

Grid spacing ∼ 100 − 10 m

LMD Mars physics
radiative transfer (dust and CO2 ), soilmodel, vertical mixing, microphysics (H2 O
and CO2 ), lifting/sedimentation, chemistry

LMD Mars GCM fields
initial profiles only, periodic boundaries

MGS hi-res dataset
topography, thermal inertia, albedo
prescribed dust scenario[Spiga et al., QJRMS 2010]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 9Outline
1

Methodology

2

Katabatic flows

3

Gravity waves

4

Deep convection

5

Boundary layer (“shallow”) convection

6

Water-ice clouds

7

Venus cloud layer

8

Conclusion
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 10

Olympus Mons

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 11

Energy budget for Martian surface
Surface energy budget
F LW + F SW = G + H s + LE

[Savijärvi and Kauhanen, QJRMS 2008]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 12

Energy budget for Martian surface
Surface energy budget
F LW + F SW = G + H s + LE
→ radiative equilibrium[Savijärvi and Kauhanen, QJRMS 2008]

Topography

Surface temperature[outputs from the UK Mars GCM]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 13

Thermal structure around a mountain on Earth

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 14

Thermal structure around a mountain on Mars

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 15

Katabatic and anabatic winds
Nighttime downslope

Daytime upslope[Spiga and Forget JGR 2009; Spiga et al. Icarus 2011]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 16

Katabatic winds over Olympus Mons

[Spiga and Forget, JGR 2009; Spiga et al., Icarus 2011]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 17

Nighttime “warm katabatic ring”[Spiga et al., Icarus 2011]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 18

Surface temperature at night, Olympus Mons
MGS / TESOMEGA[Spiga et al., Icarus 2011; Gondet and Langevin, pers. comm.]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 19

Katabatic wind over Antarctica[Parish et al., 1983]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 20

Near-surface regional winds: northern polar cap

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 21

Near-surface regional winds: northern polar cap
Frost streak and dune mapping

Mesoscale modeling[Data: Howard Icarus 2000 and Massé et al. EPSL 2012]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 22

Troughs influence katabatic winds
Results from LMD mesoscale modeling with resolution 2 km

[Smith et al. JGR 2013]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 23

Polar trough clouds on Mars

[Smith and Holt Nature 2010, Smith et al. JGR 2013]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 24

Katabatic flow jumps [a.k.a. Loewe phenomena]
Mars NPLD troughs

Earth Antarctica coasts[Left: HRSC image from Smith et al. JGR 2013; Right: NOAA satellite image.]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 25

Katabatic jumps [a.k.a. Loewe phenomena][Australian Antarctic Division website]

A. Spiga et al.

(LMD / UPMC)[Yu and Cai BLM 2006; see also Pettré and André JAS 1991]

Mesoscale and microscale modeling

Slide 26

Five nested domain zooming in one polar trough!
Horizontal resolutions: 20 km / 6.7 km / 2.2 km / 740 m / 250 m

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 27

Troughs influence katabatic winds
Results from LMD mesoscale modeling with resolution 2 km

[Smith et al. JGR 2013]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 28

Hi-res modeling of katabatic jumps in troughs
Potential temperature (traces adiabatic motions)

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 29

3D simulations of katabatic jumps in polar troughs
Vertical velocity at longitude -43◦ E in nest 5

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 30

Hi-res modeling of katabatic jumps in troughs
maps are shown about 100m above local surface

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 31

Interpretation of trough clouds[Smith et al. JGR 2013; Smith and Holt Nature 2010]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 32

A proposed scenario for the evolution of troughs
Spiral troughs analogous to terrestrial bedforms known as cyclic
steps. Developed with the ice surface, not later or independently.
[Smith et al. JGR 2013]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 33

Outline
1

Methodology

2

Katabatic flows

3

Gravity waves

4

Deep convection

5

Boundary layer (“shallow”) convection

6

Water-ice clouds

7

Venus cloud layer

8

Conclusion
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 34

Gravity Waves [GWs] and their sources[MGS/MOC Image]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 35

GWs are ubiquitous on Mars e.g. Mariner 9 images[Briggs and Leovy, BAMS 1974]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 36

Putative GWs on OMEGA surface pressure maps

[Spiga et al., JGR, 2007]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 37

Mapping of gravity waves by O2(a1∆g ) airglow
OMEGA airglow observations

Mesoscale polar modeling[Altieri et al. JGR 2012]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 38

Mapping of gravity waves by O2(a1∆g ) airglow
OMEGA airglow observations

Mesoscale polar modeling[Altieri et al. JGR 2012]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 39

GW events observed in entry profiles
Viking [Seiff and Kirk 1977] Pathfinder [below] MGS and ODY [Fritts et al. 2006]
MERs [Withers and Smith 2006] Phoenix [Withers and Catling 2010][Schofield, Science 1997; Magalhaes et al. JGR 1999]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 40

Mesospheric CO2 clouds[MEx HRSC, Määttänen et al. Icarus 2010][MEx OMEGA, Montmessin et al. JGR 2007]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 41

A link between GW activity and CO2 clouds?

Clancy and Sandor GRL 1998
CO2 ice clouds should form within thetemperature minima of tidal and GWs
in the mesosphere and be fairly
common phenomena at low-to-mid
latitudes during day/night[McConnochie et al. Icarus 2010]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 42Variability of mesospheric CO2 clouds
Recent observations by OMEGA, TES, SPICAM, HRSC, THEMIS, CRISM ...

[Vincendon et al. JGR 2011]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 43

Global Circulation ModelingRole of thermal tides in the formation of cold pockets propitious to CO2 clouds

T profiles night (dash) / day (full)Spatial variations T - Tsat

[Ls is 0 − 30◦ , latitude and longitude 0◦ . Gonzalez-Galindo et al. Icarus 2011]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 44

3D GW simulation with 30 m s−1 rightward wind
δx = 5km, δz ∼ 1km, model top 180 km with 50-km sponge layer[Spiga et al. GRL 2012]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 45

Gravity waves & subcondensation pockets
Full: Large-scale profile. Dashed and envelope: + resolved mesoscale waves[Spiga et al. GRL 2012]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 46

Spatial variations of GW filtering → S maps
Northern spring CO2 clouds

Regions/seasons with observed mesospheric CO2 clouds feature
propitious atmospheric conditions for GW propagation.

[Spiga et al. GRL 2012]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 47

Wave-induced PSCs with τ ∼ 1 over Antarctica[Noel et al. JGR 2009]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 48

Idealized simulations of gravity-wave perturbations[Spiga et al. GRL 2012; Listowski et al. Icarus 2014]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 49

Microphysics of ice growth from pure gas phase
New theory formulated by Listowski et al. JGR 2013

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 50

CO2 cloud microϕ within GW-induced cold pockets
Using new theory formulated by Listowski et al. JGR 2013

[Listowski et al. Icarus 2014]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 51

CO2 clouds w/ meteoritic condensation nuclei
Daytime clouds (70-80 km)

Nighttime clouds (90-100 km)[Listowski et al. Icarus 2014]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 52

Outline
1

Methodology

2

Katabatic flows

3

Gravity waves

4

Deep convection

5

Boundary layer (“shallow”) convection

6

Water-ice clouds

7

Venus cloud layer

8

Conclusion
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 53

The “OMEGA storm” witnessed by Mars Express
A complex, cumuliform, dust storm in Terra Meridiani at Ls = 135◦

[Adapted from Määttänen et al. Icarus 2009]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 54

Mesoscale simulation
LMD-MMM with tracers[Spiga & Forget JGR 2009]
Dust radiative transfer and2-moment transport scheme[Madeleine et al. JGR 2011]
Recent dust optical indices[Wolff et al. JGR 2009]
Terra Meridiani site [OMEGA]
181 × 181 × 101 grid points
7 km horizontal grid spacing∼ 700 m vertical grid spacingwith model top at 1 Pa
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 55

Afternoon. Local time 1400

[Spiga et al. JGR 2013, arxiv 1208.5030]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 56Afternoon. Local times 1400, 1600, 1800

[Spiga et al. JGR 2013, arxiv 1208.5030]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 57

“Rocket dust storms”!
Rapid and powerful vertical transport of dust particles[Left picture extracted from Hergé Casterman 1954]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 58

... or: “conio-cumulonimbus”
Dust-driven (κoνιoς) deep convection on Mars

[Left picture downloaded from NOAA website]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 59

Rocket dust storm [a.k.a. conio-cumulonimbus]
Dust-driven deep convection on Mars

(DS) Optical depth

SW heating rate

Vertical wind

[Spiga et al. JGR 2013, arxiv 1208.5030]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 60

Afternoon. Local times 1400, 1600, 1800

[Spiga et al. JGR 2013, arxiv 1208.5030]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 61

Evening. Local times 2000, 2200, 0000

[Spiga et al. JGR 2013, arxiv 1208.5030]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 62

Detached layers of dust: MCS observations[Heavens et al. JGR 2011 (part 1 & 2)]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 63

Nighttime. Local times 0200, 0400, 0600

[Spiga et al. JGR 2013, arxiv 1208.5030]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 64Morning. Local times 0800, 1000, 1200

[Spiga et al. JGR 2013, arxiv 1208.5030]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 65

With simplified lifting (storm area only, σ = 5 mN m , α = 2 × 10
−2

30°E

4.0
3.6
3.2
2.8
2.4
2.0
1.6
1.2
0.8
0.4
0.0

30°E

4.0
3.6
3.2
2.8
2.4
2.0
1.6
1.2
0.8
0.4
0.0

0°

5°S

10°S
20°E

5°N

0°

5°S

10°S
20°E

5°N

0°

5°S

10°S
20°E

5°N

0°

5°S

10°S
20°E

5°N

0°

5°S

10°S
20°E

Altitude (km)

30°E

4.0
3.6
3.2
2.8
2.4
2.0
1.6
1.2
0.8
0.4
0.0

5°N

Altitude (km)20°E

Altitude (km)

30°E

4.0
3.6
3.2
2.8
2.4
2.0
1.6
1.2
0.8
0.4
0.0

10°S

Altitude (km)

30°E

4.0
3.6
3.2
2.8
2.4
2.0
1.6
1.2
0.8
0.4
0.0

0°

5°S

Altitude (km)

30°E

5°N

Altitude (km)

t

4.0
3.6
3.2
2.8
2.4
2.0
1.6
1.2
0.8
0.4
0.0

40
35
30
25
20
15
10
5
0
15

40
35
30
25
20
15
10
5
0
15

40
35
30
25
20
15
10
5
0
15

40
35
30
25
20
15
10
5
0
15

40
35
30
25
20
15
10
5
0
15

40
35
30
25
20
15
10
5
0
15

−3 m−1 )

3.0

0800LT

2.4
1.8
1.2
0.6

20

25
East Longitude (deg)

30

35

0.0

3.0

1000LT

2.4
1.8
1.2
0.6

20

25
East Longitude (deg)

30

35

0.0

3.0

1200LT

2.4
1.8
1.2
0.6

20

25
East Longitude (deg)

30

35

0.0

3.0

1400LT

2.4
1.8
1.2
0.6

20

25
East Longitude (deg)

30

35

0.0

3.0

1600LT

2.4
1.8
1.2
0.6

20

25
East Longitude (deg)

30

35

0.0

3.0

1800LT

2.4
1.8
1.2
0.6

20

25
East Longitude (deg)

30

35

0.0

[Spiga et al. JGR 2013, arxiv 1208.5030]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 66

Implications of dusty deep convection on Mars
In addition to the impact on dust distribution:+ importance of mesoscale processes+ impact on global circulations (heat & momentum budget,
predictability, planetary waves); GCM parameterization needed!
+ impact on regional/global dust storms and their dynamics;+ vertical transport of water vapor and chemical species;+ generation of strong electric fields;+ source of gravity waves;+ atmospheric hazard for robotic and human exploration;+ comparative planetology perspectives.

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 67

The onset of the MY25 global dust storm[Made after Thermal Emission Spectrometer by Smith et al. 2001]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 68

A regional storm near Hellas (Ls = 185◦)
lifting ⇒threshold u∗t = 0.8 m s−1

A. Spiga et al.

(LMD / UPMC)

efficiency α = 2 × 10−5 m−1

Mesoscale and microscale modeling

Slide 69

Rocket dust storms in MY25 global dust storm?

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 70

Outline
1

Methodology

2

Katabatic flows

3

Gravity waves

4

Deep convection

5

Boundary layer (“shallow”) convection

6

Water-ice clouds

7

Venus cloud layer

8

Conclusion
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 71

Turbulent convection in daytime boundary layer
Simulated through Large-Eddy Simulations [LES]↓ Vertical ↑← Horizontal →[Meridiani simulation for Exomars risk assessment]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 72

Turbulent convection in daytime boundary layer
Simulated through Large-Eddy Simulations [LES]

Animation: xz section showing tracer transport[Spiga et al. QJRMS 2010; Colaitis et al. JGR 2013]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 73

Friction velocity predicted by LES computations
Background wind is 30 m s−1

Maximum map

Histogram[Mulholland et al. Icarus 2015]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 74

Microscale wind variability resolved by LES[Spiga and Lewis the Mars Journal 2010]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 75

Dust devils observed by Spirit

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 76

Mars PBL phenomena: Imagery
Dust devils

Cloud streets[Pancam on Spirit Rover][Mars Orbital Camera on Mars Global Surveyor]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 77

LES: daytime pressure minima in each point

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 78

Graffitis martiens ! Champ de dunes Arabia Terra[HiRISE, Mars Reconnaissance Orbiter, 2009]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 79

In measurements: Exponential or power law?
Exponential [Pathare et al. 2010]

A. Spiga et al.

(LMD / UPMC)

Power law [Lorenz et al. 2009 2011]

Mesoscale and microscale modeling

Slide 80

Specific LES for dust devil studies
Dynamical settings
LMD-LES by Spiga et al. QJRMS 2010
10 m grid spacing [timestep: 1/8 s]
369 × 369 × 101 grid points
Model top : 6 km
No background wind

Phoenix environmental settings
Season Ls = 90◦ [see Ellehoj et al. JGR 2010]
Initial temperature profile: early morning conditions from MCD
Soil properties: TI = 200 tiu and A = 0.2
Dust opacity τ = 0.3
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 81Convective vortices in LES

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 82

Detecting convective vortices and their sizes
In pressure fields predicted by Large-Eddy Simulations

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 83

Variations with local time
For domain-wide quantities

detected

A. Spiga et al.

(LMD / UPMC)

maxsizemaxdrop

Mesoscale and microscale modeling

Slide 84

Size distribution of convective vortices in 10 m LES
Histogram with logarithmic axes and bins [Lorenz Icarus 2011; Newman Stat. Mech. 2005]

Strict size criterion

A. Spiga et al.

(LMD / UPMC)

Generous size criterion

Mesoscale and microscale modeling

Slide 85

Distribution of pressure drop in 10 m LES
Histogram with logarithmic axes and bins

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 86

Mars Express radio-occultations[Hinson et al., 1999][Hinson et al., 2008]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 87

BL depth variability: observations vs. models

Lower plains [Amazonis]

Higher plateaus [Tharsis][Spiga et al., QJRMS 2010]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 88

Energy budget, bottom of mixed layer(free convection conditions)

∂θ
cp
=
∂t

p0
p

!R/cp

h

i

JLH + JLW + JSW − cp

Mars
∂θ
∼
∂t

p0
p

!R/cp

∂hw 0 θ0 i
∂z

JLW
cp

Earth (arid terrains)∂θ∂hw 0 θ0 i∼−∂t∂z[Spiga et al., QJRMS 2010]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 89

Dimensionless analysis of Mars mixed layerz
hw 0 θ0 i=F00hw θ imaxzi

hw 0 2 i
z
2 = V
zi
W∗




[Spiga et al., QJRMS 2010]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 90

Large-Eddy Simulations: sensitivity study
Boundary layer height[Exomars risk assessment for Meridiani candidate case]A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 91

Outline
1

Methodology

2

Katabatic flows

3

Gravity waves

4

Deep convection

5

Boundary layer (“shallow”) convection

6

Water-ice clouds

7

Venus cloud layer

8

Conclusion
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 92

MGS nighttime radio-occultations
Amazonis (blue) vs. Tharsis (orange). Lat 20 − 25◦ N. Local time 4am. Ls = 140◦

Temperature

Potential temperature[Hinson et al. Icarus 2014]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 93

Nighttime mixed layers and possible causes
Mixed layers

Water ice clouds[Left: Hinson et al. 2014; Right: Wilson et al. 2007]

PBL depth

Gravity waves[Left: cf. Colaitis et al. 2013; Right: Creasey et al. 2006]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 94

Possible causes for nighttime mixed layers+ daytime convective boundary layer+ convective dust storm+ gravity wave propagation and breaking+ H2 O ice clouds

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 95

Large-scale effect of radiatively-active H2O clouds[Madeleine et al. GRL 2012]
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 96

Tharsis summer clouds in daytime Ls ∼ 120◦

[LMD mesoscale model]

A. Spiga et al.

(LMD / UPMC)[Wilson et al. GRL 2007]

Mesoscale and microscale modeling

Slide 97

Tharsis summer clouds in nighttime Ls ∼ 120◦

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Mesoscale and microscale modeling

Slide 98

Mesoscale simulations of radiatively active clouds
Water ice clouds shaded, potential temperature contoured

With RAC

A. Spiga et al.

(LMD / UPMC)

Without RAC

Mesoscale and microscale modeling

Slide 99

Nighttime mixed layers
Latitude 20 − 25◦ N / local time 4am / northern summer Ls = 140◦

MGS occultations

Mesoscale simulation[Hinson et al. Icarus 2014, Spiga et al. in preparation]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 100‘Radiative’ convection in H2O ice clouds at night

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(LMD / UPMC)

Mesoscale and microscale modeling

Slide 101‘Radiative’ convection in H2O ice clouds at night

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(LMD / UPMC)

Mesoscale and microscale modeling

Slide 102

Convective mixing caused by nighttime IR coolingof H2O ice clouds+ A change of perspective about Martian H2 O ice clouds+ Mixing of water vapor, heat, momentum . . .
+ Strong vertical motions? (high-res runs ongoing!)+ Source of gravity waves?
+ Impact on precipitation? Comparison with Phoenix LIDAR?
+ Large-scale effects?

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 103

Outline
1

Methodology

2

Katabatic flows

3

Gravity waves

4

Deep convection

5

Boundary layer (“shallow”) convection

6

Water-ice clouds

7

Venus cloud layer

8

Conclusion
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 104

Venus convective & wavy cloud layer[Markiewicz et al. Nature 2007]

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 105

Venus Large-Eddy Simulations
with prescribed radiative forcing+ Modeling work reference: Baker etal. 1998; Imamura et al. 2014
+ Work in progress (M2 internship ofM. Lefèvre).
+ 200m horizontal resolution
181 × 181 grid points+ GCM SW & LW heating rates atlatitude 30◦

A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 106Convective mixing within the cloud layer
Potential temperature

A. Spiga et al.

(LMD / UPMC)

Vertical wind

Mesoscale and microscale modeling

Slide 107

Convective cells: typical of penetrative convection
Top of convective layer

A. Spiga et al.

(LMD / UPMC)

Middle of convective layer

Mesoscale and microscale modeling

Slide 108

Vertical eddy heat flux

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(LMD / UPMC)

Mesoscale and microscale modeling

Slide 109

Outline
1

Methodology

2

Katabatic flows

3

Gravity waves

4

Deep convection

5

Boundary layer (“shallow”) convection

6

Water-ice clouds

7

Venus cloud layer

8

Conclusion
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 110Rich mesoscale and microscale meteorology!
+ Powerful slope winds; spectacular polar katabatic jumps.
+ Gravity waves: ubiquitous and strong perturbations (CO2 clouds)+ Rocket dust storms: radiatively-induced deep convection+ PBL convection: not-so-shallow, radiatively controlled (6= Earth)+ Water ice clouds could be convective in the night+ Towards comparative planetology with the Venus case

Selected references and contact+ Papers in PDF available
http://www.lmd.jussieu.fr/~aslmd+ E-Mail aymeric.spiga@upmc.fr+ Twitter @aymeric_spiga
A. Spiga et al.

(LMD / UPMC)

Mesoscale and microscale modeling

Slide 111