1. SOAR 2007 Ocean Circulation

2. Coriolis Force: All moving objects are deflected to their right in northern hemisphere to their left in southern hemisphere

3. Tropical Cyclone Olyvia Hurricane Isabel Coriolis Force Northern Hemisphere  Moving objects deflected to their own right. Northern Hemisphere  Moving objects deflected to their own right. Southern Hemisphere  Moving objects deflected to their own left. L Storms rotate counterclockwise L Storms rotate clockwise

4. Temperature Controls Sunlight heats land, water, air  Land warms, heats air  Air circulates  Convection cells  warms -> expands -> rises  cools -> contracts -> sinks  Water circulates  Currents driven by wind & Earth rotation  Water temperature increases SLOWLY  Large energy change needed for small temp. change Sunlight heats land, water, air  Land warms, heats air  Air circulates  Convection cells  warms -> expands -> rises  cools -> contracts -> sinks  Water circulates  Currents driven by wind & Earth rotation  Water temperature increases SLOWLY  Large energy change needed for small temp. change

5. Atmospheric Circulation Sunlight heats ground Ground heats air, drives convection from subsolar latitude Sunlight heats ground Ground heats air, drives convection from subsolar latitude Maximum Insolation Subsolar latitude is 23.5º N/S on the solstices Subsolar latitude is 0º on the equinoxes

6. Moist air rising  stormy Dry air falling  Arid

7. Pressure Zones Pressure Zones: air motion is vertical so there is little wind!

8. Wind Zones Winds named for direction they are from Westerlies NE Trades SE Trades Easterlies Doldrums Horse Latitudes Polar Front Windless zones names vary

9. Wind Zones But the continents and oceans mess it up! Westerlies NE Trades SE Trades Easterlies Doldrums Horse Latitudes Polar Front Nice Pattern …

10. Earth’s Oceans Most common compound on Earth  Covers 71% of surface area  Land area on Earth = surface on Mars  1.36 billion km 3 (326 million mk 3 )  70% of us by weight  Major constituent of most plants & animals Originated from  Outgasing of Volcanos (continues)  Bombardment by comets (much reduced)  Present volume established 2 by ago  Quantity in equilibrium Most common compound on Earth  Covers 71% of surface area  Land area on Earth = surface on Mars  1.36 billion km 3 (326 million mk 3 )  70% of us by weight  Major constituent of most plants & animals Originated from  Outgasing of Volcanos (continues)  Bombardment by comets (much reduced)  Present volume established 2 by ago  Quantity in equilibrium

11. Location of Water Southern Hemisphere  Moderates climate  Earth closest to sun in January (southern summer)  Antarctica surrounded  Strong winds, currents  Isolates Antarctic High  within “polar vortex”  Traps CFC’s, Destroys ozone Pacific Ocean  Covers ½ the Earth  Navigated by Polynesians and Chinese in ancient times? Southern Hemisphere  Moderates climate  Earth closest to sun in January (southern summer)  Antarctica surrounded  Strong winds, currents  Isolates Antarctic High  within “polar vortex”  Traps CFC’s, Destroys ozone Pacific Ocean  Covers ½ the Earth  Navigated by Polynesians and Chinese in ancient times? Mosaic of Antarctica from Galileo spacecraft Westerlies Easterlies

12. Location of Water Oceans 97.22%  Pacific48%4280 km(14 kft) deep  Atlantic28%3930(13 kft)  Indian20%3960(13 kft)  Arctic 4%1205( 4 kft) Oceans 97.22%  Pacific48%4280 km(14 kft) deep  Atlantic28%3930(13 kft)  Indian20%3960(13 kft)  Arctic 4%1205( 4 kft) Percentage of freshwater Percentage of surface water

13. Surface Currents Move Heat Mapped by rubber duckies, bottles

14. World Surface Currents Driven by wind, Coriolis, continents Distribute heat from equator toward poles Driven by wind, Coriolis, continents Distribute heat from equator toward poles

15. Gyres: Circular Currents Turning and turning in the widening gyre The falcon cannot hear the falconer; Things fall apart; the centre cannot hold; William Butler Yeats, The Second Coming North Atlantic Gyre

16. Gyres Circular currents Eckman transport “mounds” water  pushes water  to surface current  Coriolis deflection balances gravity Circular currents Eckman transport “mounds” water  pushes water  to surface current  Coriolis deflection balances gravity Sea Level isn’t level!

17. Sea Level Sea level varies due to  changes in local gravity (subsurface structure)  currents (Eckman transport) Mean Sea Level  Monitored by satellites Sea level varies due to  changes in local gravity (subsurface structure)  currents (Eckman transport) Mean Sea Level  Monitored by satellites High Low Residuals = departure from normal Click for Quicktime Movie of Sea surface height and temperature.

18. Surface Currents: Pacific Kuro Siwo warm current to north North Pacific Drift brings warm water eastward California current brings cold water south Some flow into arctic ocean Oya Siwo: cold current soutward past Asia East Australian warm current to south West Wind Drift circles Antarctcia Cold Peruvian current brings fish toward shore

19. Surface Currents: Atlantic West Wind Drift dominates south Atlantic currents Gulf Stream feeds North Atlantic Drift, dominates north Atlantic currents COLD Labrador current drives subsurface currents Brazilian & Benguela currents circle south Atlantic COLD Canaries current past Africa

20. Regional Surface Currents Equatorial Currents  Drive upwelling in east, spreading in west Equatorial Currents  Drive upwelling in east, spreading in west Currents driven by trade winds Water leaving shore pulls water up from below: upwelling Water deflects N & S due to continents & Coriolis

21. Slackened trade winds allow warm water to slosh east, stopping upwelling of nutrient- rich water Regional Current Variations ENSO – El Niño Southern Oscillation  Trade winds & equatorial currents slacken ENSO – El Niño Southern Oscillation  Trade winds & equatorial currents slacken Normal trade winds push warm surface water to Asia allowing upwelling of cold, nutrient-rich, water near South America

22. 1997-98 El Niño building … 1997-98 El Niño fading … ENSO Trigger unknown Sea Surface Temperature monitored for signs of building El Niño Trigger unknown Sea Surface Temperature monitored for signs of building El Niño

23. Currents & Ocean Life Nutrients  compounds of nitrogen, silicon, phosphorous  minerals  carried by upwelling cold water Phytoplankton  Fish food (bottom of the food chain)  CO 2 sink (absorb ½ Earth’s CO 2 )  Some toxic (algae blooms, “red tides”) Fish  Prefer living in warmer water Best fishing where cold & warm water meet!  eg. The Outer Banks Nutrients  compounds of nitrogen, silicon, phosphorous  minerals  carried by upwelling cold water Phytoplankton  Fish food (bottom of the food chain)  CO 2 sink (absorb ½ Earth’s CO 2 )  Some toxic (algae blooms, “red tides”) Fish  Prefer living in warmer water Best fishing where cold & warm water meet!  eg. The Outer Banks

24. Regional Current Variations PDO – Pacific Decadal Oscillation  Discovered in 1996 by Steven Hare researching connection between Alaska Salmon & Pacific climate  Warm (+) = Warm equatorial waters In positive phase since April 2001  Cool (-) = Warm water at high latitudes PDO – Pacific Decadal Oscillation  Discovered in 1996 by Steven Hare researching connection between Alaska Salmon & Pacific climate  Warm (+) = Warm equatorial waters In positive phase since April 2001  Cool (-) = Warm water at high latitudes

25. Regional Current Variations PDO – Pacific Decadal Oscillation  Currently in Positive phase (since April 2001)  Fisheries in northeast pacific very productive PDO – Pacific Decadal Oscillation  Currently in Positive phase (since April 2001)  Fisheries in northeast pacific very productive

26. Regional Current Variations Gulf Stream  Keeps Europe warm!!  Drives worldwide currents Gulf Stream  Keeps Europe warm!!  Drives worldwide currents

27. Deep Ocean Currents Thermohaline circulation  Density of sea water  increases with salinity  decreases with temperature  Evaporation  decreases water surface temperature  increases salinity  Gulf Stream  warm surface water evaporates in N. Atlantic cools, increases salinity ⇒ sinks to bottom Thermohaline circulation  Density of sea water  increases with salinity  decreases with temperature  Evaporation  decreases water surface temperature  increases salinity  Gulf Stream  warm surface water evaporates in N. Atlantic cools, increases salinity ⇒ sinks to bottom Cold, salty water sinks to bottom. Warm surface water gets colder and saltier than subsurface water.

28. North Atlantic Downwelling Gulf Stream  Bring warm water north … keep Europe warm!  Cools, salinates, sinks, pulling more north Gulf Stream  Bring warm water north … keep Europe warm!  Cools, salinates, sinks, pulling more north

29. North Atlantic Downwelling Gulf stream waters sink to bottom  Flow South along ocean bottom  Drives Deep water circulation Gulf stream waters sink to bottom  Flow South along ocean bottom  Drives Deep water circulation

30. Deep Ocean Circulation Great Conveyor Belt moving HEAT  circuit takes about 2000 years Great Conveyor Belt moving HEAT  circuit takes about 2000 years

31. Deep Ocean Circulation Great Conveyor Belt moving HEAT  circuit takes about 2000 years Great Conveyor Belt moving HEAT  circuit takes about 2000 years

32. Ocean Conveyor Belt Can shut Down with too much fresh water 100 trillion m 3 = 100 x 10 12 m 3 = 10 14 m 3 = 10 14 m 3 x (1 km/1000 m) 3 = 10 14 m 3 x (1 km 3 /10 9 m 3 ) = 10 5 km 3 100 trillion m 3 = 100,000 km 3 = 24,000 mi 3

33. Thermohaline Shutdown? 13,400 years ago Lake Iroquois drained through lake Champlain and Hudson Valley into Atlantic Jeffrey Donnelly, WHOI, December 2004, “Catastrophic Flooding from Ancient Lake May Have Triggered Cold Period ”WHOICatastrophic Flooding from Ancient Lake May Have Triggered Cold Period

34. Thermohaline Shutdown? 13,300 years ago Lake Candona formed from remnant of Lake Iroquois Jeffrey Donnelly, WHOI, December 2004, “Catastrophic Flooding from Ancient Lake May Have Triggered Cold Period ”WHOICatastrophic Flooding from Ancient Lake May Have Triggered Cold Period

35. Thermohaline Shutdown? 13,100 years ago Lake Candona increases as glacier continues retreating Jeffrey Donnelly, WHOI, December 2004, “Catastrophic Flooding from Ancient Lake May Have Triggered Cold Period ”WHOICatastrophic Flooding from Ancient Lake May Have Triggered Cold Period

36. Thermohaline Shutdown? 13,000 years ago Lake Candona drains through St. Lawrence Valley, seawater intrudes as Champlain Sea Jeffrey Donnelly, WHOI, December 2004, “Catastrophic Flooding from Ancient Lake May Have Triggered Cold Period ”WHOICatastrophic Flooding from Ancient Lake May Have Triggered Cold Period

37. Thermohaline Shutdown Gulf Stream stops warming Europe  Europe cools dramatically Gulf Stream stops warming Europe  Europe cools dramatically Lake Iroquois draining through Hudson Valley: Intra-Alleroid Cold Period Lake Candona draining through St. Lawrence Valley: Younger Dryas

38. CurryCurry, WHOI, OCCI The oceans have absorbed about 30 times more heat than the atmosphere since 1955 Oceans 18.2 x 10 22 J Atmosphere 6.6 x 10 21 J The oceans have absorbed about 30 times more heat than the atmosphere since 1955 Oceans 18.2 x 10 22 J Atmosphere 6.6 x 10 21 J Ocean Changes Temperature rising  Cause of more and more powerful hurricanes? Temperature rising  Cause of more and more powerful hurricanes?

39. Ocean Changes Salinity  Decreasing in north Atlantic Salinity  Decreasing in north Atlantic cf. Curry, WHOI, OCCICurry

40. Ocean Changes Salinity  Decreasing at high latitude  Increasing at low latitude Salinity  Decreasing at high latitude  Increasing at low latitude “ … deep waters have become less salty in critical North Atlantic locations, where salty, dense waters sink to drive the global ocean circulation system... ”

41. Ocean Changes Salinity  Decreasing at high latitude  Increasing at low latitude Salinity  Decreasing at high latitude  Increasing at low latitude “Global warming may be intensifying evaporation, adding more fresh water vapor to the atmosphere and leaving tropical oceans relatively saltier.”

42. Regional Current Variations North Atlantic Oscillation  Known since 19 th Century  Positive  strong Gulf Stream  warm winter & spring in Scandinavia & E. US  cool along east coast of Canada & west Greenland  Negative  dry in E. N.Am  wet in S. Europe North Atlantic Oscillation  Known since 19 th Century  Positive  strong Gulf Stream  warm winter & spring in Scandinavia & E. US  cool along east coast of Canada & west Greenland  Negative  dry in E. N.Am  wet in S. Europe

43. NAO www.jisao.washington.edu Mostly positive since mid 1970’s

44. NAO Negative Phase mid 1950’s - 1970

45. NAO Mostly positive since mid-70’s

46. Ocean Variations Atlantic Multidecadal Oscillation  Sea Surface Temperature in North Atlantic Atlantic Multidecadal Oscillation  Sea Surface Temperature in North Atlantic

47. Atlantic Multidecadal Oscillation  Correlates with numbers of major hurricanes … and southwestern droughts! Atlantic Multidecadal Oscillation  Correlates with numbers of major hurricanes … and southwestern droughts! Ocean Variations Not perfect correlation … what else is going on?

48. Atlantic Hurricanes & ENSO  Number & Strength of hurricane increases with La Niña Atlantic Hurricanes & ENSO  Number & Strength of hurricane increases with La Niña Ocean Variations

49. Oceans’ Effects on Climate Absorbs & releases heat S L O W L Y  moderates climates  Ogdensburg has longer growing season than Potsdam!  Potsdam has harsher climate than Venice  moves heat around globe  moves heat from equator to poles  moves heat from surface to depths  transfers heat to atmosphere  evaporation absorbs heat  condensation releases heat Absorbs & releases heat S L O W L Y  moderates climates  Ogdensburg has longer growing season than Potsdam!  Potsdam has harsher climate than Venice  moves heat around globe  moves heat from equator to poles  moves heat from surface to depths  transfers heat to atmosphere  evaporation absorbs heat  condensation releases heat

50. Properties of Water General properties  Stable (hard to tear apart)  Versatile solvent (universal solvent)  Polar properties  Give rise to surface tension  Capillary action  Responds to electric fields  Solid floats in the liquid  Ponds freeze on top, ice insulates water!  Water most dense as liquid at 4  C General properties  Stable (hard to tear apart)  Versatile solvent (universal solvent)  Polar properties  Give rise to surface tension  Capillary action  Responds to electric fields  Solid floats in the liquid  Ponds freeze on top, ice insulates water!  Water most dense as liquid at 4  C

51. Properties of Water Present as solid, liquid, gas on Earth  Gas & solid on Mars & most places  Solid and liquid (?) on Europa Polar molecule H 2 O  Oxygen  8 p +, 8 n o, 8e -  Hydrogen  1 p +, 1 e -  e - tend to hang around Oxygen Making that side negative Present as solid, liquid, gas on Earth  Gas & solid on Mars & most places  Solid and liquid (?) on Europa Polar molecule H 2 O  Oxygen  8 p +, 8 n o, 8e -  Hydrogen  1 p +, 1 e -  e - tend to hang around Oxygen Making that side negative

52. Heat Properties of Water High latent heats  1 calorie = 4.186 Joules High Heat Capacity  High energy gain/loss to change temperature High latent heats  1 calorie = 4.186 Joules High Heat Capacity  High energy gain/loss to change temperature

53. Energy Transfer by Water Specific Heat  Energy absorbed or released to change temp. Specific Heat  Energy absorbed or released to change temp. SubstanceSpecific Heat (Joule/K/kg) Air (50  C)1050 Iron or Steel460 Lead130 Glass840 Quartz762 Granite804 Sandstone1088 Shale712 Soil (average)1050 Wood (average)1680 Ice2100 Steam2050 Water4168 Raising 1 kg (1 l ) of water 1°C absorbs 4,168 Joules 10 cm square cube of water 1 kg 4000 Joules ≈ energy to lift 400 kg or 900 lb 1 m

54. Energy Transfer by Water Latent Heat  Energy absorbed or released to change phase Latent Heat  Energy absorbed or released to change phase Evaporating 1 kg (1 l ) of water absorbs 2,257,000 Joules 10 cm square cube of water 1 kg 2,257,000 Joules ≈ energy to lift 225,700 kg or 507,000 lb 1 m Substance Specific Heat (Joule/kg) vaporizationfusion Alcohol879,000109,000 Water2,257,000333,500

55. Energy Transfer by Water Latent heat effects weather Evaporating water absorbs energy from water, cooling it. Condensing water releases energy to air, heating it.

56. Energy Transfer Convection – hot stuff moves Conduction – hot stuff heats neighbors Radiation – heat moves as IR radiation Convection – hot stuff moves Conduction – hot stuff heats neighbors Radiation – heat moves as IR radiation

57. Source Regions & Climate Prevailing winds over warm ocean (hot & humid) Prevailing winds over cold ocean (mild climate) Prevailing winds over big continent (harsh climate) Prevailing winds over cold ocean (mild climate)

58. Surface Currents: Atlantic Prevailing winds over warm ocean (rainforest) Prevailing winds over warm ocean (VERY mild climate) Prevailing winds over continent (harsh climate) Winter winds over BIG continent … dry Summer winds over warm ocean … monsoons! Potsdam Venice