1. Southern Globec: Snow and Ice Studies
photo D. Costa
D. Martinson, R. Smith, D. Perovich, B. Elder, S. Stammerjohn, K. Claffey
Chris Fritsen, Jeramie Memmot, Sarah Marshal, Angela Gibson, Shonna Dovel

2. Snow and Ice measurements
Snow and ice varies spatially and evolves temporally
Interested in ice cover as a
habitant
barrier
Snow and ice physical properties
Snow and ice optical properties
Time series - buoys

3. Physical properties: bridge watch
Hourly observations
ASPECT protocol
Ice type,thickness,fraction
Mean thickness = 46 cm
Mean concentration ~ 0.8

4. Physical properties: surveys
Measured every meter
snow depth
ice thickness
freeboard
flooded layer
interface temperature
Selected sites
snowpits
ice cores
Robert
6 August 2001
Snow depth Mean = 23 cm Standard deviation = 9 Range = cm
Ice thickness Mean = 71 cm
Standard deviation = 50
Range = cm
67 % flooded

5. Physical properties: surveys
6 August
9 August

6. Physical properties: surveys
Summary of 400+ holes
Snow depth Mean / median = 16 / 11 Standard deviation = 11
Ice thickness Mean / median = 62 / 44
Standard deviation = 44
Freeboard Mean/median = -0.9/ 0.0
Standard deviation = 9.5

7. Physical properties: snowpits
Selected snowpits
Vertical profiles of temperature density
grain size
grain type
Mean density = .25 g cm-3

8. Physical properties: ice cores
Profiles of
- T,S, nb
- structure
- crystallography
- d O18
About 30 sites
Date: 28 July Event 21 Lat. 66o 21'.6 S Long. 70o 43'.1 W Thickness: 33 cm Granular: 58% Columnar: 42%

9. Optical properties “Fernando” 11 August (1300) Snow depth = 28 cm
8 cm of new snow
20 cm of slush.
Ice thickness = 44 cm
Peak ~ 490 nm
Ice is “clean”

10. Optical properties TR-6 Robert 6 August 2001 Mean transmittance
- PAR:
- UV-B:

11. Time series: buoys 4 buoys 2 simple barometric pressure position
air temperature
2 complex, have in addition
snow depth
ice thickness
ice temperature
ocean temperature
spectral irradiance
Enlarged Area
August 2001
November 2001

12. Time series: buoys Robert 6 August 2001 Latitude = 68o 04
Longitude = 70o 13
20oC changes common
Major snowfall
Little change at ice bottom
Air
Snow
Water

13. Time series: ice growth
Lots of snow, 130 cm
Little change at bottom
What if?
Negative freeboard
=> flooding
=> ice growth
Air
Snow
Ice
Ocean

14. Time series: light levels
3 irradiance sensors
Above ice, below ice, in ocean
Each sensor had 4 wavelengths (412, 442, 491, and 555 nm)
Steady increase in incident
Peaks, valleys => sunny, cloudy
Decrease in transmittance => increase in snowdepth

15. Summary Ice is a mess! Granular ice common Flooding and freezeback
Surface growth of ice
Mean snow depth = 16 cm
Mean ice thickness = 62 cm
Light transmittance < 1%
Peak of 2-5% at ~ 490 nm
Time series
1 m of snowfall
60 cm of snow-ice?
Steady increase in incident
Not in transmittance

16. Web page, CD-ROM
Coming soon