Quiz #1, Part 1 results

1. Quiz #1, Part 1 results (You can see the statistics yourself in “My Grades”)

2. Quizzes, Part 2 Marking rubric posted, with examples from student answers to the Practice Quiz, Part 2(VISTA homepage  Quizzes link on homepage  Rubric...)

3. Hydrosphere II: Surface ocean circulation w/continents Goals for Today • PREDICT whether upwelling or downwelling will occur along a coastline, given surface wind direction • PREDICT the direction of wind-driven surface ocean currents anywhere on Earth with any continental configuration. • LIST differences between western and eastern boundary currents in subtropical gyres

4. RELEVANCE Fisheries Heat transport Digital Vision Trans-portation Christopher Duncklee

5. Surface Ocean Currents Marshak, Figure 18.10

6. Clicker question: The wind often blows from south to north along the coastline of Peru. Toward what direction is the Ekman transport? A. Generally northward B. Generally southward C. Generally toward the shoreD. Generally away from shoreE. There is no Ekman transport because of the presence of a continent. 12°S Peru WIND

7. Wind, Ekman transport, geostrophic flow, and coastal upwelling: Geostrophicflow Peru Lower Ekmantransport Higher WIND

8. Along shorelines: Southern hemisphere upwelling Upwelling of deeper water http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/eln/upw.rxml

9. Along shorelines: Northern hemisphere upwelling

10. Coastal upwelling Along shorelines: Sea surfacetemperature, South Africa Blue = cold Red = warm

11. Coastal upwelling Along shorelines: Chlorophyll, South Africa Red = more chlorophyll Blue = less chlorophyll

12. Clicker question: This image shows chlorophyll concentration in the ocean off the Arabian peninsula in a particular season in a particular year. This pattern is related to monsoon circulation in India. WHAT SEASON IS IT IN THIS IMAGE? A. Summer monsoonB. Winter monsoonC. In between summer & winterD. There’s not enough information given Peru Red – highBlue - low

13. In the open ocean: Equatorial upwelling Sea Surface Temperature TAO Project Office/PMEL/NOAA

14. Equatorial upwelling In the open ocean: Chlorophyll-ain surface water Convergence Blue = LowGreen/yellow = High Divergence Convergence

15. Surface Ocean Currents Equatorial currents ERROR ALERT! The Equatorial Counter Current should be NORTH of the equator!

16. Intertropical Convergence Zone (thermal equator) NE Trades Light wind! Rising air! ITCZ Geographic equator SE Trades SouthAmerica Which direction is the Ekman transport? NOAA

17. Intertropical Convergence Zone (thermal equator) NE Trades Light wind! SE Trades Ekman transport Where are the convergences and divergences? NOAA

18. Equatorial dynamic topography Convergence at ~30ºN Divergence at ~10ºN Light wind! Convergence at ~4ºN Divergence at 0º Convergence at ~30ºS Where are the hills and valleys? NOAA

19. Clicker Question: Toward what direction does the geostrophic current flow under the ITCZ (between about 4°N and 10°N)? High ~30ºN • To the west  • To the east  • To the NE • To the NW • There’s no geostrophic current there Low ~10ºN High ~4ºN Low 0º High ~30ºS NOAA

20. Follow-up Clicker Question: Toward what direction does the geostrophic current flow between about 0°N and 4°N? High ~30ºN • To the west  • To the east  • To the NE • To the NW • There’s no geostrophic current there Low ~10ºN High ~4ºN Low 0º High ~30ºS NOAA

21. Equatorial dynamic topography High ~30ºN Low ~10ºN Light wind! High ~4ºN Low 0º High ~30ºS Which direction are the geostrophic currents? NOAA

22. Equatorial geostrophic currents North Equatorial Current North Equatorial Counter Current South Equatorial Current NOAA

23. JULY Circular wind patterns

24. Ekman transport under the Bermuda High

25. Geostrophic flow around a SUBTROPICAL GYRE Coriolis force Geostrophic Flow Horizontal pressure gradient force

26. Sea surface height:North Atlantic subtropical gyre -80 cm 0 cm 70 cm (Mercier and Le Traon) Red = High, Blue = low

27. H Asymmetrical ocean gyres (N. Hem.) Western intensification H Symmetric (atmospheric winds) Asymmetric (ocean gyres)

28. Steepness of mound sets flow speed ~150 cm/s ~10 cm/s 1000 – 2000 m

29. Global dynamic topography

30. Surface Ocean Currents Warm and cold currents

31. Global Sea Surface Temperature

32. Global Surface Air Temperature, July 2003

33. Summary: Surface Ocean Circulation • All major ocean currents are geostrophic, responding to pressure gradients that are set up by Ekman transport, which is driven by the wind. • Upwelling & downwelling, coastal or open ocean • Complex equatorial currents, due to continents • Subtropical gyres: Warm western boundary currents flow poleward; Cool eastern boundary currents flow equatorward. • You can apply the same principles to any situation, along a coastline or in the open ocean, to deduce the direction and strength of ocean currents. Relevance: food, heat, transportation

34. In preparation for next lecture… So far, we have considered only the circulation near the surface of the ocean. The deep ocean also moves. What’s the major driver of deep ocean circulation?

35. Extra, unused slides below this one

36. Gulf Stream Warm Core Ring

37. Gulf Stream Ring formation Warm rings north intocolder water Cold rings south intowarmer water

38. G3

39. Sea surface temperature (SST) February

40. Surface Air Temperature, January 2003

41. Sea surface Temperature (SST) August

42. Winds Drive Surface Currents Currents are Moving Ocean water…

43. Effect of Coriolis on surface ocean circulation

44. convergence convergence Ekman Transport 90o to wind direction

45. Another Look at Convergence

47. High phytoplanktonconcentration at equator purple = low chlorophyll-a light blue = higher chlorophyll-a

48. Cool SST animations athttp://svs.gsfc.nasa.gov/vis/a000000/a003300/a003389/index.html

49. Along shorelines: Northern hemisphere upwelling http://oceanmotion.org/html/background/upwelling-and-downwelling.htm

50. Along shorelines: WIND Ekmantransport Lower Higher California Geostrophicflow