1. Wintertime CO2 Frost Formation Could be the Mechanism behind H2O Ice Patches in the Martian Northern Hemisphere
By Eric Beitia
(Northern Arizona University, Flagstaff Arizona)
Project leader Dr. Timothy N. Titus
(United States Geological Survey, Flagstaff Arizona)

2. Temperature
On Mars CO2 solidifies at ~ 150 K (-123º C)
On Earth CO2 solidifies at 200 K (-73° C)
On Mars H2O solidifies at ~ 200 K (-73º C)
On Earth H2O solidifies at 273 K (0° C)
Solar longitude (Ls)
Identifies season of the planet
Each month corresponds to 30 degrees Ls

3. THEMIS (Thermal Emission Imaging System) data
266E 70N
NORTH
IR image
Temp = 190 K / 220 K
NORTH
Get rid of left crater (42E 69N)
Visible image

4. The Hypothesis of Ice Patch Formation Autumn/Winter Winter Spring
Mid-Spring
Add layer of CO2 ice under everything
Late spring
Spring/Summer
CO2 Snow
CO2 Ice
H2O Ice

5. Ice patches found
~8000 THEMIS images
24 Ice patches

6. THEMIS (Thermal Emission Imaging System) data
266E 70N
42E 69N
NORTH
NORTH
IR image
Temp = 190 K / 220 K (-83º C/-53º C)
Ls = 54 (mid-spring)
Earth time = May 2006, Mars year 28
IR image
Temp = 168 K / 216 K (-105º C/-57º C)
Ls = 61 (mid-spring)
Earth time = June 2006, Mars year 28
NORTH
NORTH
Visible image
Ls = 87 (end of spring)
Earth time = August 2006
Mars year 28
Visible image
Ls = 62 (mid-spring)
Earth time = July 2004
Mars year 27

7. TES (Thermal Emission Spectrum) data
NORTH
NORTH
266E 70N
Warm colors represent solid ice (CO2)
Cool colors represent fine grain (CO2) snow
42E 69N
Warm colors represent solid ice (CO2)
Cool colors represent fine grain (CO2) snow

8. Ice patches found
24 Ice patches with cold spot activity
24 Ice patches showed annual repetitive behavior

9. Conclusions:
We use THEMIS data to show 24 craters with
ice patch activity
Successfully found 24 ice patches that have had
cold spot activity earlier in the year with TES data
Ice Patch activity repeats yearly for all 24 craters
Future work would be to find many more craters with
similar characteristics

10. The end!!!

11. Autumn/Winter Winter Spring Spring Mid-Spring Late Spring
First we have CO2 ice from the
atmosphere freezing onto the
ground
Orographic lifting forms a CO2 cloud
that adiabatically cools forming fine
grained CO2 snow (cold spot) on the
downwind rim of the crater
The CO2 ice sublimes significantly
faster the CO2 snow
Spring
Mid-Spring
Late Spring
The CO2 snow then cold traps the
surrounding H2O molecules forming
an ice patch that covers the CO2 cold
spot
Add layer of CO2 ice under everything
CO2 then sublimes from under the
water ice patch (mid-spring)
Late spring we are left with a patch of H2O water ice on the ground
Spring/Summer
CO2 Snow
CO2 Ice
The water ice patch has sublimed by
the beginning of the summer
H2O Ice

12. The Hypothesis of Cold Spot Formation Autumn/Winter Winter Spring
Mid-Spring
Late spring
Add layer of CO2 ice under everything
Spring/Summer
The
Hypothesis of
Cold Spot
Formation
CO2 Snow
CO2 Ice
H2O Ice

13. Conclusions:
We use THEMIS and TES data to show ice patch
and cold spot correlation
Successfully found 24 ice patches that have had
cold spot activity earlier in the year
Ice Patch activity repeats yearly for all 24 craters
Future work would be to find many more craters with
similar characteristics

14. THEMIS (Thermal Emission Imaging System) data
266E 70N
42E 69N
NORTH
NORTH
Temp = 190K / 220K
Ls = 54 (mid-spring)
Earth time = May 2006
Mars year 17
Temp = 168K / 216K
Ls = 61 (mid-spring)
Earth time = June 2006
Mars year 17
NORTH
NORTH
Need a distribution slide before this (Location Map). Recheck mars years
Ls = 62 (mid-spring)
Earth time = July 2004
Mars year 16
Ls = 87 (end of spring)
Earth time = August 2006
Mars year 17

15. THEMIS (Thermal Emission Imaging System) data
285E 69N
42E 69N
NORTH
IR image
Temp = 225K / 235K
IR image
Temp = 168K / 216K
NORTH
Present the problem
Visible image
285E 69N
Visible image
42E 69N

16. Use this slide for corresponding IR and vis

17. THEMIS (Thermal Emission Imaging System) data
266E 70N
285E 69N
NORTH
IR image
Temp = 190 K / 220 K
IR image
Temp = 227 K / 238 K
NORTH
Get rid of left crater (42E 69N)
Visible image
Visible image