1. QUIZ 1, PARTS 1 & 2 Open TODAY (Wed, Sept 23 rd )! The quiz will be open for 12 hours 3 pm Wednesday to 3 am Thursday Go to either “Quizzes” from the homepage OR “Assessments” on the left panel. Reminder: we’re counting your top 3 marks from 5 quizzes (Read the syllabus for details!) Please register your clickers by FRIDAY!

2. Goals for Today 1.COMPARE the relative sizes of different water reservoirs and residence times of a water molecule within these reservoirs. 2.PREDICT the result of processes that change the flux between different water reservoirs. 3.PREDICT locations of open-ocean upwelling and downwelling, given surface wind direction. 4.PREDICT the direction of wind-driven surface ocean currents for a simplified, water-covered, rotating Earth with no continents. Hydrosphere I: Hydrologic cycle, surface ocean circulation

3. RELEVANCE Fresh water Pollution: the Pacific Plastic Patch Theferrisfiles.com Ocean productivity

4. ICE and SNOW CLOUDS and WATER VAPOUR OCEAN GROUNDWATER LAKES RIVERS and STREAMS transport evaporation groundwater flow riverine flow percolation precipitation More CLOUDS and WATER VAPOUR

5. Notes

6. Reservoir sizes and fluxes http://ww2010.atmos.uiuc.edu/(Gl)/guides/mtr/hyd/bdgt.rxml 97.6% <0.001% 2.4%

7. Clicker Question: Look at the 4 kitchen sinks below. In which sink does a drop of water spend the LONGEST average time before draining out? A 30 L 20 L/hr 10 L 5 L/hr 30 L 15 L/hr 15 L 5 L/hr C B D

8. Clicker Q: Earth’s atmosphere has about 13000 km 3 of water in it. Water precipitates out at a rate of about 1300 km 3 per day. What is the average RESIDENCE TIME of water in the atmosphere? 13000 km 3 1300 km 3 /day A.1 day B.10 days C.13 days D.100 days E.130 days

9. Phase Changes Freezing -80 cal/g Condensing -540 cal/g Melting +80 cal/g Evaporating +540 cal/g Solid: ICE Gas: Water Vapour Liquid: Water Notes

10. The Gulf Stream

11. Surface Ocean Currents Marshak, Figure 18.10

12. How does the wind affect the ocean surface?

13. Air-sea frictional coupling

14. Fridtjof Nansen and the Fram (1893-1895)

15. What did Nansen observe? Coriolis effect on iceberg motion Notes

16. Fridtjof Nansen and the Fram (1893-1895) ICE WIND ~20-40º

17. Net Force Wind Direction of Motion Average Flow Ekman spiral Northern Hemisphere Garrison, Figure 9.5

18. Ekman Spiral and Ekman Transport Net transport is 90º from the wind direction Ekman layer

19. Notes (From Chereskin (1995)) Wind Observing the Ekman Spiral

20. Clicker question : Given the wind arrow below, which direction is the Ekman transport (northern hemisphere)? WIND A B C D E

21. Ekman transport WIND Ekman transport Ekman transport Northern Hemisphere (to the right) Southern Hemisphere (to the left) WIND Ekman transport WIND Ekman transport Water

22. Ekman transport: rotating Earth, no continents Wind Ekman transport DIVERGENCE CONVERGENCE D D D C C C C

23. Dynamic topography: Divergence & Upwelling DEPTH

24. Dynamic topography: Convergence & Downwelling

25. Ekman transport: Sea surface height Wind Ekman transport DIVERGENCE CONVERGENCE Low High

26. Clicker question: Wind In what direction do the WIND-DRIVEN GEOSTROPHIC SURFACE CURRENTS flow, at position “X”? First, figure out the directions of the horizontal pressure gradient force in different latitudinal bands… X A. To the NW B. To the SW C. To the N D. To the W E. To the E

27. Clicker question: Wind In what direction do the WIND-DRIVEN GEOSTROPHIC SURFACE CURRENTS flow, at position “X”? First, figure out the directions of the horizontal pressure gradient force in different latitudinal bands… X A. To the NE B. To the SE C. To the S D. To the W E. To the E

28. Geostrophic flow: (rotating Earth, no continents) Wind Ekman transport Low High Geostrophic Current Horizontal Pressure Gradient Force = Coriolis Force

30. The hydrologic cycle describes the movement of water among different reservoirs, including the rates of transfer and residence times. Water in all its forms plays crucial roles in Earth’s climate system. Surface ocean currents are wind-driven. Ekman transport – 90º to the RIGHT of the wind (N. hemisphere) 90º to the LEFT of the wind (S. hemisphere) ET sets up convergence (downwelling) and divergence (upwelling) Conv/Div  pressure gradients Pressure gradients+Coriolis  geostrophic flow Summary: Hydrologic Cycle & Surface Circ Relevance: fresh water, ocean productivity, pollution

31. In preparation for next class… So far, we have considered geostrophic wind- driven surface ocean currents on a planet with no continents. What’s going to happen when we add continents? To start, imagine a coastline, like Vancouver Island, that’s oriented approximately NW-SE. Say the wind was blowing from the NW for several days continuously. What would be the response of the surface ocean? Ekman? Pressure gradient? Geostrophic current?