Surface Water

1
Surface Water Deep
Water CIRCULATION
2

• NOTES
• Turn in Homework -2
• Pick Up Homework 1
• Homework 3 Assigned Due Next Wednesday
• MIDTERM
• Get 2 GREEN SCANTRONS from Bookstore
• 2 pencil
• Exam based on Lecture Notes
• 40 Multi Choice Qs
• 5 Short Answer

3

• World Ocean Circulation
• Traditionally divided into 2 components
• 1) Surface Water Circulation
• 2) Deep Water Circulation
• Actually Both Influence each other. . .
• Best TERM WORLD OCEAN Circulation
• Well Review each separately for Simplicity Sake
  . . .

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• World Ocean Circulation
• Based on Dynamic Physical Oceanography
• Describes Ocean based on
• Physical laws conservation equations in
  conjunction with
• Atmospheric and oceanographic observations
• GOAL
• Quantify flow patterns property distributions
  in the Ocean
• Many PRACTICAL Applications
• Ship Routing
• Search and Rescue
• Marine pollutant trajectories
• OUR GOAL
• Explore the Nature of Ocean Circulation
• become aware of Forces that govern .

http//www.mindfully.org/Plastic/Nike-Pacific-Dump
-Ebbsmeyer.htm
5
OUTLINE

• World Ocean Circulation
• Foundations of Physical Oceanography
• Motion in the Ocean
• Upwelling/Downwelling
• Patterns of Surface water Circulation
• Patterns of Deep water Circulation
• What Drives Deep water Circulation
• Global Conveyer Belt

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• Foundations of Physical Oceanography
• Ben Franklin (1706-1790)
• US Postmaster General (reduce transit time)
• Publishes First Maps of Gulf Stream
• By 1800 many
• circulation patterns
• worked out by seaman
• Via Trial and error
• Little understanding of
• Why?

7

• Foundations of Physical Oceanography
• Many Early Scientists contributed to
• Modern view of Ocean Circulations Patterns
  (1750-1900)
• Based on Convection Currents Model
• Ben Thompson, Henry Ellis, John Buchanan, Alex
  Buchan
• Alfred Merz, Geoarge Wust
• 1958, Henry Stommel (1920-1992)
• Proposed global model of abyssal circulation . .
  .
• Most Important Physical Oceanographer- All time

8
Deep H2O formation
Deep flows. . ..
Deep flows
Subsurface flows. . ..
1958, Henry Stommel (1920-1992) Proposed global
model of abyssal circulation
Deep H2O formation
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OUTLINE

• World Ocean Circulation
• Foundations of Physical Oceanography
• Motion in the Ocean
• Upwelling/Downwelling
• Patterns of Surface water Circulation
• Patterns of Deep water Circulation
• What Drives Deep water Circulation
• Global Conveyer Belt

10

• Motion in the Ocean Challenge Questions
• The existence of the 4 Big Gyres- Where are they?
• How do they arise? See next slides
• What direction are their rotations Clockwise or
  Counterclockwise?
• 
  WHY? see next slides

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• Motion in the Ocean
• The existence of the Gyres
• How do they arise? V. Walfrid Ekman (1861-1930)
• Understand Ekman Transport

((Wind stress)) Friction drags layer below And so
on. . .
Remember In N. Hemisphere Coriolis deflects this
to Right
NOTE Arrows indicate -direction -intensity
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• Motion in the Ocean
• Ekman Transport
• Challenge Question?
• What 2 phenomena occur to the currents as you go
  deeper in depth layers?
• 1. The currents deflect Right (N.
  Hemisphere)
• 2. The currents intensity weakens

NOTE Arrows indicate -current
direction -current intensity
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• CHALLENGE Question
• Why do the Gyres spin Clockwise or Counter
  Clockwise?

N. Hemisphere S. Hemisphere
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• CHALLENGE Question

RECALL The Westerlies The Trade Winds

• Provide Wind stress
• Under influence of Coriolis
• Curves currents to right
• Via Ekman Transport

clockwise
How Should this look in the S. Hemisphere?

• NOTE
• There is a mistake
• in the Text
• where is it and why?

S. Pacific Gyre should be counter clockwise
15
v

• Gyres
• N. Hemisphere Clockwise
• S. Hemisphere Counter Clockwise
• What is so important about Gyres anyway?

clockwise
Counter clockwise
Anthropogenic activity causing harm See the
Great Ocean wasteland. . .KQED
http//www.youtube.com/watch?vg9fEbqxyNl0
16

• WHAT CAN YOU DO?
• Youre probably not Going to Stop Using all
  Plastics
• RECYCLE
• RECYCLE
• RECYLCE!
• Santa Cruz one of the best Countys for
  RECYCLING!!! (1-6 or higher!)
• JUST DO IT
• Set an EXAMPLE for you FAMILY, Friends
• the Next Generation ?

17

• Geostrophic Flow The Hill in the Gyre
• What does geostrophic stand for?
• Earth-turning refers to flow under influence
  of Coriolis
• EKMAN Transport Directs H2O to middle of Oceans
  (Gyres)
• Creates sloping Sea Surface (a Hill)
• H2O flows from High Pressure to Low pressure
• Forms geostrophic currents (gyres)
• A balance of
• Horiz. Press. Gradient
• Coriolis force

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• Geostrophic Flow The Hill in the Gyre
• Another rendition

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• Geostrophic Flow The Hill in the Gyre
• Consequences .. (see TOPEX Satellite Alimeters)
• Elevated Sea Surface Heights across the Oceans

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• Geostrophic Flow The Hill in the Gyre
• Satellite Jason 2001
• 32 cm difference in elevation b/w Pt. A vs Pt. B

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• Upwelling/Downwelling
• What is upwelling?
• The flow of subsurface waters to the surface
• What are the two types
• Coastal
• Equatorial

EQUATORIAL Upwelling
nutrients
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• Satelite Image of Upwelling
• Cooler waters in Purple

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• Upwelling
• COASTAL Upwelling (e.g. California)
• In N. California, what direction does the Coastal
  wind Come From?
• North (Alaska) Winds . . . .
• Surface waters are
• blown west
• (via Ekman transp.)
• Deep H2O is upwelled to fill gap
• Cold water upwelled ?

24

• Downwelling
• What is it?
• the movement of water downward in the water
  column
• Warmer surface water migrates onto the coastline
• ?

VS
Versus heading out to sea (UPWELLING)
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• Serious Upwelling in N. California
• Lots of biological Production f/ Nutrients
  (photosynthesis)
• Kelp Forests
• marine life etc.

Warmest Spot N. of Pt. Conception
SATELLITE IMAGE -Cold Water (Purple)
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OUTLINE

• World Ocean Circulation
• Foundations of Physical Oceanography
• Motion in the Ocean
• Upwelling/Downwelling
• BREAK
• Patterns of Surface water Circulation
• Patterns of Deep water Circulation
• What Drives Deep water Circulation
• Global Conveyer Belt

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• Patterns of Surface water Circulation
• Harald Sverdrop (1888-1957)
• Early theoretical Understanding
• Effects of a Boundary (continent) on Ocean
  Circulation
• His Theories allowed for calculation of surface
  flows
• via wind stress
• In his Honor created
• Water transport unit the Sverdrup 1x106 m3
  sec -1

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• Patterns of Surface water Circulation
• What does the Long-term averages of Surface H2O
  transport look like in terms of surface
  circulation?

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• Western Boundary Currents
• What are they and What do they arise from?
• Currents located along the western sides of Ocean
  basins
• Arise from an intensification of Gyre circulation
• In response to variations in the Coriolis effect
  with lattitude

Where are they Below?
v
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• Western Boundary Currents
• All fast moving narrower then most currents
• e.g. in N. Atlantic - Gulf Stream (Most Famous)
• 2.3 m s-1 (Knots)
• Transports Warm H2O from Gulf of Mexico to N.
  Atlantic

Florida
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• Western Boundary Currents
• e.g. in N. Pacific what Current?
• Kuroshio gt 2.5 m s-1 (gt5 Knots) 2 miles sec!
• Flow is complicated, Japan archipelago ? wakes,
  eddies etc.

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• Western Boundary Currents
• e.g. in S. Atlantic what Current?
• Brazil Current 2.2 m s-1 (lt5 Knots)
• Forms Highly Productive Large Marine Ecosystem
  (LME)
• aka Patagonian Shelf

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• Western Intensification
• Challenge Question?
• What is it - And what is it caused by?
• Increase in flow rates of W. boundary currents
  caused by
• Coriolis effect which
• Increases _at_
• Higher latitudes

TAKE HOME Western Boundary Currents Fast/
Narrow, b/c Coriolis What about Eastern
Boundary Currents? Next slide. . ..
CORIOLIS Force STRONGEST Stronger modest weak
Gulf Stream or Kuroshio
Latitude
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• Eastern Boundary Currents examples?
• e.g. California Current
• Slow moving (1 foot/ sec)
• Bring cool water coastal Upwelling ? Moderate
  Climate
• aka Mediterranean
• Also produce considerable fog

35

• Equatorial Counter Currents
• Weak seasonal currents return some (warm) flow
  East
• May play a role in Hurricane formation. . .

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• Equatorial Counter Currents
• Satellite imagery, warmer temp (yellow)

Hurricane Alley
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• Antarctic Circumpolar Current (ACC)
• Only continuous current unimpeded by land masses
• Important exchange pt for Waters or all three
  Oceans
• Atlantic, Pacific, Indian

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• Summary
• Warm Cold Surface Water Currents

39
OUTLINE

• World Ocean Circulation
• Foundations of Physical Oceanography
• Motion in the Ocean
• Upwelling/Downwelling
• Patterns of Surface water Circulation
• Patterns of Deep water Circulation
• What Drives Deep water Circulation
• Global Conveyer Belt

40

• Patterns of DEEP Water Circulation - T-S Diagrams
• What are they and what are they used for?
• Temp vs Salinity Diagrams
• mea. _at_ different pressures (depths)
• Allow for the determination of diff. types of
  water masses
• How they are influencing mixing and current flow,
  their properties etc.. . .

T-S Diagram
Surface Ocean
Deep Ocean
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Patterns of DEEP Water Circulation - T-S Diagrams
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• Patterns of Deep water Circulation
• Confirming your knowledge
• What is Needed to Form Deep Water?
• Cold air/H2O temperatures, high salinity ?
  (downward flux)
• Colder/ salty water dense
• sinks
• e.g. N. Atlantic
• Gulf Stream transports
• Warm/Salty H2O Greenland
• S. of Greenland
• Cold Air cools water
• Cool/salty water sinks. . .
• N.Atlantic deep water
• aka (NADW)

43

• Patterns of Deep water Circulation
• Ocean is Stratified (layered)- influenced by
• Thermocline
• Rapid change in temperature
• Pycnocline
• What is it?
• Rapid change in density
• (salinity Temp)

Influences the Major Water Masses . . .
44
NOTES

• Saltier
• More abundant
• Influ deep circulation
• Over greater region
• Thought to confer greatest
• Shut down of NADW
• Abrupt climate changes

Colder Most dense in World
45
OUTLINE

• World Ocean Circulation
• Foundations of Physical Oceanography
• Motion in the Ocean
• Upwelling/Downwelling
• Patterns of Surface water Circulation
• Patterns of Deep water Circulation
• What Drives Deep water Circulation
• Global Conveyer Belt

46

• Deep water Circulation
• Challenge Question Current Philosophy
• What Drives Deep water Circulation?
• _at_ Highest latitudes (downward flux sinking)
• Density changes form (Cold salty) ? sinking H2O
• _at_ lower Latitudes
• Upward flux (upwelling) does the WORK (pulling)

upwelling
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• Places where the seawater is cold enough and
  salty enough to form bottom water.

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OUTLINE

• World Ocean Circulation
• Foundations of Physical Oceanography
• Motion in the Ocean
• Upwelling/Downwelling
• Patterns of Surface water Circulation
• Patterns of Deep water Circulation
• What Drives Deep water Circulation
• ?Global Conveyer Belt

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• All this Deep Water movement ?
• Global Conveyer Belt
• aka ThermoHaline Circulation
• What is it?
• Thermo (temp) haline (salt) dependent
  circulation
• Heat of Earths oceans dissipated from
  circulation process. .

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• Global Ocean Conveyer Belt (ThermoHaline
  Circulation)
• Wally Broeckers Model shows deep H2O
  formations returns
• Broecker et al., 1991, Oceanography
• Challenge Question?
• Where are the 2 major cites for DEEP water
  Formation?
• N. Atlantic Deep Water (NADW)
• Antarctic Bottom Water (AABW)

NADW
AABW
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• The Global Conveyer Belt aka

http//www.youtube.com/watch?v3niR_-Kv4SM
FOR More Animated Effects See
http//www.youtube.com/watch?vL9zjmC8InKA
http//www.youtube.com/watch?vMZbsMlr9WRIfeature
related
52

• NOTE Global Conveyer Model
• Oversimplified representation
• Schmitz Model (1995)
• More accurate
• Ocean Mixing
• complex
• Surface
• Intermediate
• Deep Waters all mix

FINAL THOUGHTS Know the 2 Major -Cites of Deep
Water formation -Why and how they would occur
53

• NOTES
• Turn in Homework -2
• Pick Up Homework 1
• Homework 3 Assigned Due Next Wednesday

SEE you FRIDAY ((?) brrrr)
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Fig. 9.21
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Fig. 9.22
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PHOTOS
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Opener
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Page 165
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Fig. 9.1
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Fig. 9.13
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Fig. 9.16
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TABLES
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Tab. 9.1
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Tab. 9.2
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Tab. 9.3