1. Periglacial Landscapes

2. Organization 1.Climate 2.Soils 3.Landforms and Hydrology 4.The front line on issues of climate change

3. Polar Climates

4. Dominated by Polar High Dense, cold air flows equatorward

5. Extreme Seasonal Changes 24 days in summer, 24 night in winter

6. Ice Cap Climate Mean monthly below zero

7. Tundra Climate harsh winters low average temperatures little snow or rainfall too short summer season for trees Influenced by permafrost, a layer of permanently frozen subsoil in the ground. The surface soil, which tends to be rocky, thaws in summer to varying depths. The combination of frozen ground and flat terrain impedes drainage of water. Held at the surface or soaking the upper layer of soil, the water forms ponds and bogs in low areas

8. Source: Solomon, 2000 Effect of Latitude or Altitude Our focus for this lecture

9. Animations – click on image Alaska Animations – focus on Arctic tundra where get extremes of temperature & little precipitation

10. Soils Poorly Developed In Rocky Areas

11. Soils Experience overturning from permafrost activity (gelisol)

12. Soils: position is very important Upland soils: entisols Poorly developed Lowland soils: histosols Peat – plant accumulation

13. In low-lying areas where water collects from permafrost melting, get accumulation of organic remains of plants called PEAT, or in soil-speak: histosol

15. Why does peat accumulate ? Production by plants exceeds decomposition Abundant growth due to available moisture during growing season Preservation of plants (cool conditions) Saturated conditions - slow, anaerobic decomposition by methanogenic bacteria When plants decay (with drying & warming), release of methane Videos of peat: Scottish Highlands; JumpingScottish HighlandsJumping

16. Landforms & Hydrology Permafrost Ice Wedge Polygons Pingo Patterned Ground Solifluction Rocky Uplands Rivers

17. Cryosphere Dominates Frozen Ice Caps & Frozen Water in Soil Frozen Ice Caps & Frozen Water in Soil (warning: very big file: 180 MB)

18. Permafrost Permanently frozen water in the ground

19. Underground mine in permafrost (Yakutsk, Permafrost Institute, Dr. P. Konstantinov)

20. When thaws, creates “thermokarst” Pipelines Break Roads Cave In

21. Buildings Collapse if not properly insulated

22. Natural Permafrost Cycle Freeze thaw = key to periglacial topography

27. Northwest Territories

29. Phoenix Lander on Mars Site selected because polygons suggest permafrost might be resent

30. Pingo Northwest Territories

31. Pingo

33. Can grow as water moves to ice core

34. Patterned Ground – Rocky & Flat Active layer “churning” sorts rocks

35. Northwest Territories

36. RMNP

37. Striped Ground, Greenland

38. Solifluction: sloped ground in finer materials flows (oozes)

39. Kinnard Research, Excavation, Yukon Excavation of lobe Buried organic layer

40. Topographic Position Rocky uplands: patterned ground Low slopes: solifluction lobes Lowlands: ice wedge polygons

41. Rocky Uplands Felsenmeer – rock block field broken up by frost weathering

42. Steep slopes with lots of frost- weathered rock: Rock Glaciers Ice core & seasonal freeze/thaw moves rocks

43. Possible Rock Glaciers on Mars?

44. Rivers Winter – frozen Spring – thaw Summer – very aggressive erosion

45. Sudden Thaw Floods Lena River Siberia

46. Breakup Timing http://aprfc.arh.noaa.gov/rwpindex.php

47. River Ice: Unique Arctic Hydrology All rivers experience some ice effect –In some instances, runoff events associated with river ice have produced extreme and dangerous flooding events River Ice interacts and obstructs the passing of floods Blockage causes water levels far higher than those under open water conditions

48. YUKON RIVER LIFTED AND SHIFTED SHEETS Shifted ice – large ice sheets that have moved short distances from their original locations as rising water levels create wider areas of open water into which the ice can move http://aprfc.arh.noaa.gov/rwpindex.php

49. TYPICAL RUN OF ICE May be 10-20 miles in length Reach of large moving sheets (near breakup front) Reach of mixed sheets, pans, and chunks Reach of mostly chunks Subsequent runs are mainly chunks http://aprfc.arh.noaa.gov/rwpindex.php

50. YUKON RIVER Ice run – a continuous length of moving ice http://aprfc.arh.noaa.gov/rwpindex.php

51. NULATO RIVER ICE JAM Ice jam – an ice run that has stopped moving due to any of a variety of reasons; this very small jam has broken sheet ice holding back a small run of chunk ice http://aprfc.arh.noaa.gov/rwpindex.php

52. ICE JAM IMPACTS Upstream from the jam... Fast water level rise Packed ice chunks Potential flooding http://aprfc.arh.noaa.gov/rwpindex.php

53. Flooding impact Water outside the channel http://aprfc.arh.noaa.gov/rwpindex.php

54. KUSKO RIVER, ANI VILLAGE FLOODING Village flood – water spreading into a village that covers roads or threatens buildings http://aprfc.arh.noaa.gov/rwpindex.php

55. Lena River Delta Yukon R. Delta

56. Hansen, Scientific American, March 2004 Arctic Warming at the Front Line of Global Change

59. Dramatic changes in Arctic Sea Ice 1979-2003: Progressive Loss of Arctic Ice Imagine an ice-free Arctic

60. Source: Corell, R. W., 2004: Impacts of a warming Arctic. Arctic Climate Impact Assessment (www.acia.uaf.edu) Cambridge University Press (www.cambridge.org).www.acia.uaf.edu

61. AnimationAnimation of Model Prediction NOAA Prediction of Arctic Sea Ice

62. Earth’s Orbital Parameters

63. Orbit and Ice Ages Tilt, Eccentricity, and Precession combine to cause variations in the amount of sunlight Earth receives...

64. Oxygen Isotope Record Oxygen isotope record of foraminefera During glacial periods, less oxygen in oceans...

66. The increase in growing season length over the last 50 years averaged for eight stations in Alaska having the longest and most consistent temperature records. Gradual Loss of Tundra (purple) as growing season lengthens

67. The future? Some modelsmodels show loss of TundraTundra (purple) From: Lawrence Livermore Laboratory