Seasonal and latitudinal distribution of water vapor

1. MODERN CLIMATE AND HYDROLOGICAL CYCLE OF MARS.A.V.Rodin, A.A.Fedorova, N.A.Evdokimova, A.V.Burlakov, O.I.Korablev1Moscow Institute of Physics and Technology, Russia; Space Research Institute, Russia . Contact: Alexander.Rodin@phystech.edu

2. Seasonal and latitudinal distribution of water vapor TES – 20-40 microns Smith 2002-2008 1.38 μm Viking1,2 MAWD MY 27 SPICAM IR Fedorova et al. 2006 Jakosky, Farmer 1984

3. Jakosky et al.1984-1995: Titov, Houben Regolith matters Clancy et al., 1996: Circulation affected by Richardson, Wilson, 2003 orbit excentricity & Montmessin et al., 2004 hemispheircal asymmetry cloud microphysics matters TES, PFS, OMEGA, SPICAM, MCS: search for zonal, seasonal and interannual variations

4. Mars Atmosphere General CirculationModel Ls = 270z=5 km • FMS dynamical core • Aerosol –consistent radiation • H2O cloud microphysics • 11.5, kz=28

5. GCM illustration of Clancy effect: aphelion-perihelion asymmetry

6. aphelion perihelion Clancy et al., 1996, Montmessin et al, 2002

7. Seasonal Mars water cycle: GCM results

8. Water vapor column distributions on Mars imply significant zonal variations: Viking/MAWD (Fedorova et al., 2004, Pankine et al.,2009) MGCM simulations Ls = 20 Ls = 90 Ls = 150 Ls = 330

9. Water vapor annual average: atmosphere-surface interactions Antipodal maxima of bound water content Mitrofanov et al., 2002 Exposure (days) of frost layer exceeding 100 m Water vapor column, pr. m

10. Annual average (contd.) H2O molecules number density provided T > 220 K Cold trap: t otal time whenT>30 K andT > 200 K, days Basilevsky et al., 2006, Nelli et al., 2006

11. Soil hydration: - significant latitudinal variations - no evident connection to the seasonal water cycle Evdokimova et al., 2010

12. MGS/TES (Pankine et al.,2009)

13. MEX/SPICAM: Spatial distribution of water vapor summer in north hemisphere Ls 95-120: 59 orbits from 72 orbits are presented Fedorova et al, 2009

14. MGCM instant water vapor column: North hemisphere [pr. mm] 180 180 180 200 60 200 50 40 100 30 100 20 10 0 0 0 0 0 Ls = 92 Ls = 113 Ls = 142

15. OMEGA: Modes 2 and 3 inNPC sublimation marked by 1.25 mm water ice band depth Ls~93-97 Ls~113-115 Ls~127-136 MGCM water column, pr µm Ls~132 Ls~94 Ls~114

16. The location of maximal wind stress at the NPC coincides with spots of enhanced ice aging Ls = 113 Ls = 137 Ls = 92 + + + + + 0 5 Near-surface wind according to MGCM (m/s) (!) NPC sublimation rate depends on dynamics of the ambient atmosphere, not just heating and relative humidity

17. Ls = 145 event: switching from mesoscale to global perturbation Ls = 137 Ls = 147 Ls = 92 Zonal flow meridional shear Decaying circumpolar vortex Emerging circumpolar vortex Meridional V-component Wave-3 pattern -5 5 -10 10 -5 5

18. Polar vortex barotropic instability: laboratory studies (Barbosa et al., 2010)

19. Mode 3 in the residual seasonal water ice deposits (left) and MGCM moisture (right) MEX/OMEGA 1.5 mm index Rodin et al., 2010 MGCM

20. South hemisphere Ls = 225 event: implications to dust cycle Near-surface dust mixing ratio (ppm) Ls = 227 Ls = 233 Ls = 220 0 50 0 50 0 50 Wave-4 pattern Wave-2 pattern Wave-3 pattern Season of the strongest transient in the South hemisphere coincides with the window of dust storm initiation

21. Conclusions • The nature of current Mars water cycle is understood; GCMs are able to reproduce observables • The role of polar caps, regolith, and clouds needs further quantitative assessment • Water cycle demonstrates a major role of low-wavenumber eddy transport in the Martian atmopsheric circulation