Improving the representation of the martian water cycle in the Global Climate Model of the LMD*

Transcription

1 Improving the representation of the martian water cycle in the Global Climate Model of the LMD* Margaux Vals, Laboratoire de Météorologie Dynamique*, Paris, Aymeric Spiga, François Forget, Ehouarn Millour CPS workshop, 28/03/2018

2 North polar cap! Martian North polar cap, MOC camera onboard Mars Global Surveyor, NASA/JPL Vertical slice of the North polar cap, image from Sharad onboard Mars Reconnaissance Orbiter, NASA/JPL

3 Martian water cycle controlled by the seasonal cycle Northern hemisphere Autumn Equinox Perihelion Northern Hemisphere Summer Solstice Northern Hemisphere Winter Solstice Aphelion Northern Hemisphere Spring Equinox

4 Martian water cycle controlled by the seasonal cycle Northern summer : sublimation of the North polar cap Northern hemisphere Autumn Equinox Perihelion Northern Hemisphere Summer Solstice Northern Hemisphere Winter Solstice Aphelion Water vapor Water ice Northern Hemisphere Spring Equinox

5 Martian water cycle controlled by the seasonal cycle Northern summer : sublimation of the North polar cap Northern hemisphere Autumn Equinox Perihelion Atmospheric condensation Northern Hemisphere Summer Solstice Northern Hemisphere Winter Solstice Aphelion Water vapor Water vapor Water ice Water ice Northern Hemisphere Spring Equinox

6 South polar cap : CO2 ice! Martian South polar cap, MOC camera onboard Mars Global Surveyor, NASA/JPL

7 Martian water cycle controlled by the seasonal cycle Northern Hemisphere Summer Southern Hemisphere Summer * Water vapor column obtained by TES on board Mars Global Surveyor, NASA/JPL

8 Numerical modelling : Global Climate Model ()

9 Main recent improvements Radiatively active clouds (Madeleine et al. 2012, Navarro et al. 2014) Improved microphysics (Navarro et al. 2014) nucleation on dust particles ice particle growth scavenging of dust particles supersaturation

10 Main remaining issues Systematic temperature inversion within nighttime clouds MGS Radio-occulta tions (D. Hinson)

11 Polar hood too thick TES

12

13 Night-time mixing layers under water ice clouds MGS radio-occultation measurements Mixing layer 250 E 195 E MGS Potential temperature profiles Mesoscale model : Horizontal res~30km vertical res~750m Spiga et al. 2017

14 High horizontal resolution c c High res~1x1 (~60x60km) Pottier et al Usual res~3,75x5,625 (~220x330km)

15 Ls=150 ; Lat=10 ; LT=2am Lon=-120 Usual vertical resolution~2,5km Lon=-120 High vertical resolution~1,2km

16 Ls=150 ; Lat=10 ; LT=2am Ls=150 Lat=10 LT=2am Lon=-120 Res~2,5km Res~1,2km High resolution Lon=-120

17 Water cloud cycle Vertical Res~2.5km Vertical Res~1.2km

18 Water cloud cycle Vertical Res~2.5km Very high vertical resolution ~ 500m? Vertical Res~1.2km

19 Water cloud cycle Vertical Res~2.5km Vertical Res~2.5km Physical Timestep twice lower than the usual one

20 Water cloud cycle Vertical Res~2.5km Vertical Res~2.5km Physical Timestep twice lower than the usual one Coupling of another process in the microphysics?

21 Conclusion & perspectives Microphysics resolution : coupling of ice particle growth and sedimentation, retuning parameters? Investigate on significant improvements of the high vertical resolution Implement improvements : Choice of a good vertical resolution Sub-grid scale clouds implementation? (A. Pottier) Dust cycle : parametrization of detached dust layers (PhD Chao Wang) Future comparisons with brandnew observations (TGO)

22 From here backup slides

23 : Vertical res~2.5km Ls=150 Lat=20 LT=2am Lon=-100 : Vertical res~500m Lon=-100 Very high resolution

24 : Vertical res~2.5km Lon=-100 : Vertical res~500m Lon=-100 Ls=150 Lat=20 LT=2am Res~2,5km Res~500m High resolution

25 Water vapour cycle TES

26 Water vapour cycle Vertical Res~2.5km Vertical Res~1.2km

27 Water vapour cycle Vertical Res~2,5km Vertical Res~1,2km Improved Coupling Particle growth sedimentation

28 Water cloud cycle TES Longitude, deg Vertical Res~1.2km

29 Water cloud cycle Vertical Res~2.5km Vertical Res~1.2km

30 Water cloud cycle Vertical Res~2,5km Vertical Res~1,2km Improved Coupling Particle growth sedimentation

31 Alizée Pottier

32 Horizontal resolution 1 x1 vs 3.75 x5.625 Alizée Pottier

33 Horizontal resolution 3.75 x x1 Alizée Pottier

34 Sub-grid scale nebulosity The sub-grid scale variability is represented by a temperature distribution Sub-grid scale nucleation, ice condensation & growth Sub-grid scale clouds & radiative transfer