1. Conditions for the appearance of interfacial liquid water at the northern hemisphere of Mars Kereszturi A. 1,2, Appere T. 3,4 1 CSFK KTM CSI Hungary, 2 NASA Astrobiology Institute TDE Focus Group 3 Laboratoire AIM, CEA-Saclay, France, 4 IPAG, Grenoble, France MPSE 2, 2014 Warsaw, Poland

2. Content: aim, background methods northern seasonal polar cap interesing units at the polar cap edge: global recession (TES scale) regional characteristics (TES scale) local occurrence (THEMIS scale) interfacial liquid water duration conclusion, comparison to south outlook

3. Aim, background interfacial water identified sites at south (Kereszturi, Rivera- Valentin 2012): Dark Dune Spots CRISM  water ice temp. modeling  180-220 K  2 weeks searching for it at north importance flow-like features possible chemical reactions habitability Methods OMEGA based mapping (12-13 km/px) TES temperature (around noon) THEMIS temprature (around noon) spatial-temporal correlation areas with H 2 O ice (1.5  m) no CO 2 ice (1.43  m) temperature (no cold trapping H 2 O) HiRISE CRISM

4. Springtime N polar cap receeding water ice annulus (Kieffer and Titus 2001, Wagstaff et al. 2008, Appere et al. 2011) H 2 O ice formation cold trapping  recondensation  on the top of CO 2 ice accummulation during CO 2 sublimation exhumation of earlier deposited below CO 2 ice Interfacial liquid water between mineral surface and water ice unfrozen mainly by Van der Waals forces local spring north treshold temperature depends on vapor content between Ls=20  70 atm. vap. increases 7  40 pr  m 3 values according to different atm. vapor content: 180 K, 190 K, 199 K Möhlmann 2004, 2010 OMEGA

5. Global recession curves overlay: TES temp. + OMEGA ice on TES spatial resolution at all of the water ice annulus interfacial liquid is possible 55  -70  N water ice: 10-30 days 45  -55  N longer duration: 80-110 days Regional recession curves „best” and „worst” (30  wide) latitude bands good: 300-330 sector subpixel mixing? shading: treshold temperatures global lines: seasonal cap edges

6. THEMIS – OMEGA overlay 200 m spatial scale analysis water ice without CO 2 ice THEMIS OMEGA: light blue CO 2, deep blue: H 2 O ice

7. THEMIS – OMEGA overlay OMEGA: continuous water ice THEMIS: more patchy but areas still exist down to the limit of spatial resolution where intrfacial liquid water exists duration 44-55  80-100 day >55  10-30 day longest duration patchy „warm” areas longest duration treshold temperatures

8. Conclusion probable interfacial liquid water at north (THEMIS scale) patchy areal occurrence in rings migratng rings location: ideal lat. zone: 44  -55  ideal long. zone: 300  -330  E duration: up to 100 day but only at noontime cummulative duration:  100 hours / Martian year paper is coming out in Icarus 2014 autumn comparison to south (N / S): N longer duration (100 / 20 days) N lower temperature (185 / 200 K) N larger area (patches: 10 km / 10 m) N: receeding water ice ring S: only small water ice patches

9. Future work lubrication by thin liquid  grain movement CRISM scale analysis  how patchy/continuous chemical processes? H 2 O 2 decomposition (accompanying poster) sulfate formation (?) conditions not far from liquid ferric-sulfate brines (south) collaboration is welcomed! Acknowledgment ESA ECS project Co 4000105405 (no. 98076) OTKA PD 105970 CNES “Système Solaire” program