Transcript Ocean Circulation - Physics Resources

Oceans
ESSTD2004
1: Overview
Exploration
Hydrologic Cycle
Every State Is An Ocean State
Heights and Depths
Moon Topography
http://cosmology.berkeley.edu/Education/DEMOS/Lunar_Topography/Lunar_Map2.html
Venus Topography
http://www.higp.hawaii.edu/~hamilton/venus.html
Jupiter – an Ocean Planet
Questions for Reflection
• All the water on land eventually reaches the
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ocean. Discuss how the area you live in impacts
the environmental quality of the ocean. Can you
describe areas that might add toxic material to
the ocean? Are there ways in which your
community works to protect the ocean?
Debate whether more money should be spent to
explore space or to explore the ocean floor.
Explain how the oceans affect Earth’s weather.
Investigations 1
• Closed-loop Mapping - Plan a round
trip, log your travels and check your
accuracy.
– http://physics.gallaudet.edu/navigate
• Shuttle Oceanography – Look for
interesting shuttle ocean photographs
– http://daac.gsfc.nasa.gov/CAMPAIGN_DOCS/OCDST/s
huttle_oceanography_web/oss_contents.html
• Global Topographic Map – Find
interesting ocean basin features.
– http://physics.gallaudet.edu/etopo5/
2: Plates and Oceans
Ocean Basins
Plate Boundaries
Seafloor Spreading
Atlantic and Pacific Basin Dynamics
Plate Subduction
Transform Fault
Questions for Reflection
• Ocean fossils and layers of sedimentary rock can
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be found on the tops of mountains. What does
that show about the Earth’s surface?
Why is the seafloor lower than the surface of the
continents?
No oceanic crust older than about 160M years is
known from the present oceans. Why are they
so young?
Would you expect lavas that erupt under water
to cool more or less rapidly than those that
erupt in air?
What would the surface of the Earth be like
without active plate tectonics?
Questions for Reflection
• How did ancient civilizations explain the
occurrence of earthquakes and volcanoes?
• Does plate tectonics operate on any other
planet in our solar system?
3: SeaWater
The Water Molecule
Water Energy Transformations
Latent Heats of Water
Seawater Composition
Global Salinity Patterns
T-S Graph
Questions for Reflection
• List important properties of water.
• Describe thermohaline circulation.
• In what major process does water get
transferred from the ocean to the
atmosphere?
• Why are temperature and salinity the most
important tracers of water masses?
• What resources are extracted from
seawater?
Investigations 3
• Measure Salinity using the GLOBE Program
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protocol
Wave Speed and Depth – Set up a rain gutter
and measure the speed of waves in water
depths of 1 cm, 2 cm,…
Thermohaline Circulation and the Rayleigh-Taylor
Instability – Experiment with “baby food” jars
studying mixing of cold, hot, salty, fresh water.
Water On the Balance – Does dipping your
finger into water on a scale change the reading?
4: Oceans and the
Atmosphere
Solar Cycle
Effect of Solar Elevation
Coriolis Effect
Global Wind Patterns
High Pressure Centers
Low Pressure Centers
Questions for Reflection
• Why are the cloud patterns we see in weather
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satellite images dominated by swirls?
Why do hurricanes not form at the equator?
Why do they not form over land? There are no
hurricanes formed in the South Atlantic Ocean.
Why?
What special conditions are necessary for
hurricanes to form?
In what major process does water get
transferred from the ocean to the atmosphere?
Why is the concentration of carbon dioxide
dissolved in seawater greater than in the
atmosphere?
Investigations 4
• Study of Hurricane Behavior link1 link2 – Where and
when do hurricanes/cyclones/typhoons occur in the
Atlantic, Pacific and Indian Oceans:
– http://weather.unisys.com/hurricane/
– http://meted.ucar.edu/hurrican/movncane/
• Global Wind Patterns – Use Quickscat data to study the
evolution of recent hurricanes (i.e. Isabel Sept 8-18,
2003) or plan your own ocean sailboat voyage.
– http://physics.gallaudet.edu/winds/web/
• Boat Races – Build boats with foam and race in a
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raingutter using wind, mousetrap, rubberband, electric
motor,… power.
CO2 and the Land and Ocean Biosphere – What is the
relation between the biosphere and atmospheric CO2?
Contrast behavior in the Northern and Southern
hemispheres.
– physics.gallaudet.edu/biosphere/co2_shtn.mov
5: Currents
Ocean Cross Section
Gulf Stream
Gulf Stream
Ekman Transport
Western Boundary Currents
Gyre Dynamics
Global Currents
Upwelling
Downwelling
El Nino Events
Questions for Reflection
• What causes the principal open-ocean
surface currents?
• Discuss why it is important to study ocean
currents. Include in your discussion ways
that plants, animals, and humans use
ocean currents.
• Why does a wind driven current not flow
in the same direction as the wind that
causes it?
Questions for Reflection
• If the thermal energy from solar radiation
is largely absorbed by the surface layers,
how can it be carried deeper?
• If higher average temperatures than now
characterized the Earth's surface and the
poles were ice free, what implications
might such conditions have for ocean
circulation?
Investigations 5
• Water Current Patterns – Study the seasonal patterns of
the equatorial currents in the Atlantic, Pacific and Indian
Oceans.
– http://physics.gallaudet.edu/currents/currents.html
• Drifters – Pick a region with interesting geography or
currents and track a drifter.
– http://w3.jcommops.org/cgi-bin/WebObjects/Argo
• Sea Surface Temperature – Search for and estimate the
intensity of El Nino events.
– http://physics.gallaudet.edu/sstdv/web/sstdv.html
• Ocean Basin Dynamics – Experiment with a computer
basin computer model to see how winds, ocean
depth/size and the Coriolis force affects water currents
and the sea level.
– http://physics.gallaudet.edu/obdv/obdv.html
Credits and Resources
• Slides from Datastreme Ocean, M. Grant Gross,
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Elizabeth Gross, American Meteoroloigical
Society, 2004.
Quickscat and Sea Surface Temperature data
from the Jet Propulsion Laboratory
– podaac.jpl.nasa.gov
• Rayleigh-Taylor Instability – Fascinating Gateway
to the Study of Fluid Dynamics, Robert F.
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Benjamin, The Physics Teacher, Vol. 37, 1999, pp
332-336
Map Images for Class Graphing
– http://physics.gallaudet.edu/mapimages/