Oceanography 10
Ocean Circulation
Figure 8.8
• PART 1:
Introduction
Solar Energy and the Seasons
Effects of the Earth’ rotation
Coriolis Effect
Earth’s changing rotational velocities
Earth’s major wind patterns
Gryres and effects of currents
•
PART 2:
Measuring Ocean Currents and Structure
•
PART 3:
General Surface Currents and their Patterns
•
PART 4:
Ocean Structure & Water Masses
Gulf Stream
flows at 55
million cubic
meters/sec,
500 times the
flow of the
Amazon
River
Figure 8.14
1
Sea surface temperatures in Celsius during the Northern
Hemisphere summer (25 degrees C = 77 degrees F)
Figure 6.5
Top picture is July, bottom is January, green and blue indicate temperatures
Oceanography 10
below 0 Celsuis and warmer temperatures are shown in red and black
Ocean Circulation
• PART 1:
Introduction
Solar Energy and the Seasons
Effects of the Earth’ rotation
Coriolis Effect
Earth’s changing rotational velocities
Earth’s major wind patterns
Gryres and effects of currents
•
PART 2:
Measuring Ocean Currents and Structure
•
PART 3:
General Surface Currents and their Patterns
•
PART 4:
Ocean Structure & Water Masses
2
Coriolis Effect
Figure 6.16
Gapard Coriolis 1792 – 1843
French Mathematician
Notice the change between 0-30 degrees = 140mph and
between 30-60 degrees = 380mph!
Oceanography 10
Ocean Circulation
60
30
0
• PART 1:
Introduction
Solar Energy and the Seasons
Effects of the Earth’ rotation
Coriolis Effect
Earth’s changing rotational velocities
Earth’s major wind patterns
Gryres and effects of currents
•
PART 2:
Measuring Ocean Currents and Structure
•
PART 3:
General Surface Currents and their Patterns
•
PART 4:
Ocean Structure & Water Masses
3
Figure 6.19
Oceanography 10
Ocean Circulation
•
PART 1:
Introduction
Solar Energy and the Seasons
Effects of the Earth’ rotation
Coriolis Effect
Earth’s changing rotational velocities
Earth’s major wind patterns
Gryres and effects of currents
•
PART 2:
Measuring Ocean Currents and Structure
•
PART 3:
General Surface Currents and their Patterns
•
PART 4:
Ocean Structure & Water Masses
4
Part 2
Measuring Ocean Currents
and Structure:
Seasoar, a modified CTD meter
can be used at the surface to ~350 meters
•
•
•
•
CTD Sensors
Satellites
Bouys
ARGO: free floating profile
floats
• Current Meters
• Doppler Meters
• Spills, Accidents
ARGO = Array for Real-Time Geostrophic Oceanography
“Argo is a global array of 3,000 free-drifting profiling floats that measures the
temperature and salinity of the upper 2000 m of the ocean. This allows for
continuous monitoring of the temperature, salinity, and velocity of the upper
ocean, with all data being relayed and made publicly available within hours
after collection.”
Doppler Current Meter
5
Drift Bottles
1956 – 1959: 33,800 bottles released
The Hansa Carrier / May 1990
Figure 8 p.236 (figure 2)
http://www.islandnet.com/~see/weather/elements/shoes.htm
Figure 8 p.237 (figure 3)
6
Oceanography 10
Ocean Circulation
•
PART 1:
Introduction
Solar Energy and the Seasons
Effects of the Earth’ rotation
Coriolis Effect
Earth’s changing rotational velocities
Earth’s major wind patterns
Gryres and effects of currents
•
PART 2:
Measuring Ocean Currents and Structure
Part 3: General Surface Current Patterns
Ekman Spiral & Transport, Gyres, Zones of Divergence and Convergence,
Upwelling and Downwelling, Geostrophic Flow,
& Boundary Currents
• PART 3:
General Surface Currents and their Patterns
•
PART 4:
Ocean Structure & Water Masses
Figure 8.1
7
Ekman Transport
Vagen Walfrid Ekman
1874 – 1954
Swedish Oceanographer
…
Why Low Pressure spins in a counter-clockwise direction
Low
Pressure
Practice Problems
If strong steady winds are blowing from the north to the south off the
coast of California, which of the following will result?
A. Downwelling
B. Upwelling
C. A zone of convergence
D. Both A and C
If strong steady winds are blowing from the south to the north off the east
coast of Southern South America, which of the following will result?
A. Upwelling and a zone of divergence
B. Downwelling and a zone of convergence
C. El Nino
D. Both B and C
Notice the change between 0-30 degrees = 140mph and
between 30-60 degrees = 380mph!
8
Geostrophic Flow
Eastern Boundary Currents
& Western Intensification
Boundary Current Characteristics
30-60 degrees changes
380mph or 613 Km/hr
0-30 degrees changes
140mph or 224 Km/hr
9
ARGO = Array for Real-Time Geostrophic Oceanography
“Argo is a global array of 3,000 free-drifting profiling floats that measures the
temperature and salinity of the upper 2000 m of the ocean. This allows for
continuous monitoring of the temperature, salinity, and velocity of the upper
ocean, with all data being relayed and made publicly available within hours
after collection.”
Figure 7.4
• Part 4
Ocean Structure and
Water Masses
Surface Zone, Pycnocline Zone
& Deep Zone
El Niño
10
El Niño / ENSO
11
Surface topography and
temperature is measured by
satellites and subsurface
temperatures are measured
by buoys.
Red is 30 degrees Celsius
(86F) and blue is 8 degrees
Celsius (~46F).
http://tao.noaa.gov/tao/jsdisplay/sel_
buoysummarytmp_ndbc.shtml
Figure 8.8
12