The Whole Earth Course

1. The Whole Earth Course Chapter 9 Hydrosphere 2 The Cryosphere Instructor: Dr. George A. Maul gmaul@fit.edu / X 7453 http://www.panoramas.dk/fullscreen2/full22.html

2. Outline of the Class • Earth’s Cover of Ice and Snow • Glaciers • Glaciated Landscapes • Sea Ice • Periglacial Landscapes and Permafrost • Summary

3. What is the Cryosphere? • Sea, lake, and river ice • Glaciers • Ice sheets • Ice caps • Ice shelves • Frozen ground such as permafrost

4. Last time we said that Earth’s Cryosphere is 43,400,000 km3 In-class Calculation: How tall would a 1 km x 1 km tower of 4.3x107 km3 stand? Volume = Height x Length x Width 4.3x107 ÷ 149.6x106 = What is the distance to the sun?

5. HOW BIG IS THE CRYOSPHERE? Approximately 3% of all the water in the hydrosphere is contained in the Cryosphere. WHERE DO WE FIND THE CRYOSPHERE? Glaciers cover about 10% of land area. Permafrost is another 20% of land area. HOW MUCH IS SEA ICE? Two-thirds of Earth’s permanent ice cover; one-thousandth of Earth’s total ice volume.

7. Past Glaciation Ice cover changes Earth’s Albedo (A) Who Cares?

8. Today’s ice and snow coverage Average snow cover in the northern hemisphere (%) during December 1992, based on data received (left) from a microwave sensor aboard a satellite. Maximum 1979-1995 What is a microwave satellite sensor?

9. MICROWAVE SENSORSDefense Meteorological Satellite Program – DMSPScanning Multichannel Microwave Radiometer - SMMR DMSP SMMR Image

10. Climate Change:Arctic Sea Ice

11. Motion of Arctic Sea Ice http://www.youtube.com/embed/hC3VTgIPoGU?rel=0

12. Antarctic Ice “Facts matter” Stephen Breyer Associate Justice, US Supreme Court

13. How would Earth’s temperature change if the ice coverage changed? What is ? QGHE: What is the greenhouse effect? CSUN: What is the solar constant? A: What is Earth’s albedo? 4: Where does the ¼ come from?

14. Stefan-Boltzmann Law Plank’s Law Iλ Circa 1879 λ Q= Units?

15. What is QGHE ?

16. IN CLASS CALCULATION: CSUN: What is the solar constant? where rsun= 696,000 km rEarth-SUN=149,600,000 km If TSUN = 5775 K, CSUN = ?

17. Albedo: Today’s value A=30%

18. Why the ¼ in our equation? Energy in: π r2 Energy out: 4π r2 By-the-way: Q is a flux, i.e. amount per unit area per unit time Units?

19. IN CLASS CALCULATION: How would Earth’s temperature change if the albedo changed from 30% to 29%? minus If TEARTH(A=30%) = 288K, TEARTH(A=29%) = ?

20. Glaciers Contorted medial moraines of Susitna Glacier in Alaska.

21. Where do we find glaciers?

22. How thick can glaciers be? How thick is 3000 m? What is the height of the Crawford Building? 28m

23. Main features of a valley glacier.

24. An expanded view of the effects of glacial ice on the geosphere.

25. What is the pressure (p) at the base of a 10,000 m thick glacier? p = ρ∙g∙h Ice movement over meltwater has less friction than over frozen surfaces.

26. IN CLASS CALCULATION: What is the pressure (p) at the base of a 10,000 m thick glacier? What are the units? What is the pressure melting point at the base of the glacier? So the ice melts at -8°C

27. Changes in a Glacier

28. Evolution of glacial carved landforms

29. Effects of glaciers on Earth’s surface are significant. Can you contrast the effects of streamflow and glaciers on sediment transport? Hint: Which one sorts sediments during transport?

30. Major glacial landforms in USA

31. Periglacial Landforms, Permafrost, Tundra Permafrost Tundra Extent Tundra Periglacial Landform

32. FeedbackWhich is positive feedback and which is negative feedback? http://www.atmosedu.com/Geol390/feedbacks.htm

33. Sea Ice Why do icebergs float? Who was Archimedes?

34. IN CLASS CALCULATION: How high does an iceberg float? We’ll need the hydrostatic equation again p = ρ∙g∙h p – pressure, ρ – density, g – gravity, h – height ρseawater=1025 kg·m-3ρice=917 kg·m-3 (ρgh)water = (ρgh)ice so hice = ?

36. What maritime disaster precipitated the formation of the International Ice Patrol?

37. Blowing up Icebergs?!?!

38. Pancake Ice – discovery of the Ekman Spiral.

39. Seasonal extent of sea ice in A. Southern hemisphere, and B. Northern hemisphere.

40. Florida Tech Student deploying FIT-built ROV under Arctic Ice What is an ROV?

41. How much frozen water is in sea ice? Sea ice is 0.1% of the total volume of ice on Earth. How much of Earth is covered with sea ice? 2/3 of Earth’s permanent ice cover is sea ice. This is approximately 5-6% of the surface area of Earth. Of what significance is sea ice in the Earth System? What happens if it all melts? What happens if more forms? Who cares?

42. Approximately 1000 km3 of glacial ice enters the sea each year as icebergs. (Can you put this number in perspective?) How wide is Florida? Please note the size of the sheets of ice breaking off!!

43. Towing Icebergs Step 1: circle iceberg Step 2: curtain iceberg Step 3: tow iceberg http://oceanexplorer.noaa.gov/edu/learning/player/lesson12/l12la1.html

44. How much heat to melt sea ice? What about the Cryosphere? Sea ice is 0.1% of Cryosphere or 0.0434 x 106km3 or 39.4 x 1018 g of ice. For ice at 00C to water at 00C 330J/g or 79 cal/g is required. Total heat required to melt sea ice is 1.3 x 1022J, or for the whole Cryosphere is 1.3 x 1025 J. For perspective, world energy consumption is approximately 4 x 1020 J/year One PB&J sandwich is about 1 million Joules!!

45. What happens if sea ice melts here? What happens if sea ice forms here? Transect along western Atlantic Ocean showing water masses and general circulation processes.

46. Post Script: Greenland Sea Deep Water Warming http://www.sciencedaily.com/releases/2013/09/130925102833.htm

47. Summary • Cover of Ice, Snow, and Permafrost is 30% • Glaciers: temperate and polar • Glacier mass = accumulation - ablation • Glaciated Landscapes: Plow, File, and Sled • Sea Ice: >60% of area, 0.1% of volume • Permafrost covers >20% of land surface

48. Next Time Chapter 10 – the oceans 70.8% of the Whole Earth’s Surface