Transcript Marine Physics Notes

Marine Physics
Chapters 6-9
JUST COPY WHAT
IS
UNDERLINED!!!!!!
Influence of Currents
on Climate
Pgs.
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Because of the area and thermal properties
of the ocean it dramatically influences global
weather and climate patterns.
Currents moderate climates- without the
currents moving heat, the world’s climates
would be more extreme.
Gulf Stream
One of the deepest
surface currentscarries heat
 Powerful, warm, swift
 Starts at the Gulf of Mexico, crosses the Atlantic Ocean
 Influences the east coast of N. America and the west
coast of Europe
 Moves warm air from
over the Gulf Stream inland
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Florida and N. Europemilder winters
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California Current
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S. California- mild climate due to the
moderating effects of the Pacific Ocean
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The southerly current along the Calif. coast brings
cool water from the north, keeping it cooler than it
normally would be in the summer
Factors that Affect
Direction and Patterns of
Major Ocean Surface
Currents
Pgs 9-3 to 9-5
#1 Wind
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Transfers energy to the water it blows across
by the force of friction on the water’s surface
Causes both surface currents and waves
Ekman Transport/Spiral= Current moves to
the right of the Wind at a 45 degree angle
Major wind belts:
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Trade winds
Westerlies
Polar Easterlies
#2 Land Masses
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interrupt the flow of ocean currents creating
closed circular current systems called gyres.
Forces currents to turn
#3 Coriolis Effect
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influences the wind by giving it a circular flow
pattern
the air deflects toward the right in the Northern
Hemisphere and toward the left in the
Southern Hemisphere- same with currents
Christopher Columbus reached the new world
thanks to the Coriolis effect
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Note: If the Earth did not rotate and remained
stationary, the atmosphere would circulate between the
poles (high pressure areas) and the equator (a low
pressure area) in a simple back-and-forth pattern. But
because the Earth rotates, circulating air is deflected.
#4 Temperature
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Convection currents
Vertical movement of currents caused by
temperature differences
Temperature divides layers of water
Deep sea vs. surface currents
Cause of the Coriolis Effect
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Pilots need to correct their flight
path based on the earth rotating
under the airplane, which is the
Coriolis effect.
Earth’s rotation- adds an
apparent sideways motion to
objects moving over the
Earth’s surface.
Tides
Pgs 10-3 to 10-24
What are Tides?
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Daily variations in the ocean’s
level
 The mean average tide
occurs later each day by 50
min
 HighLow =6 hours 13
min.
 HighHigh=12 hours 25
min.
most noticeable at the shore,
but affect the entire ocean.
Cause of Tides
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Result from the gravitational pull of the moon, and,
to a lesser degree, the sun
Earth is not a perfect sphere
Time of the month, Season, Coriolis Effect
Shape of the ocean basin
 Large, wide basins have smaller tidal ranges
 Narrow, shallow basins have larger tidal ranges
Where is the largest tidal range in the world? Bay of
Fundy
Spring and Neap Tides
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Spring tides: occur during the full moon and new
moon (they do not have anything to do with the
season Spring)
occur when the Earth, the Sun, and the Moon are
in a line- every 2 weeks
high tides are very high and the low tides are very
low
especially strong tides
Spring Tide
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Neap tides occur during quarter moon phases
occur when the gravitational forces of the Moon
and the Sun are perpendicular to one another
(with respect to the Earth).
results in a smaller difference between high and
low tides
especially weak tides
Neap Tide
Tidal Patterns &
Currents
pgs 10-21 to 10-24
Tidal Pattern
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Diurnal tide
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Semidiurnal Tide
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Single high and low
tide daily
Location: Gulf of
Mexico
Two “equal” high and
low tides
Location: east coast of
U.S.
Mixed Tide
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Two unequal high and
low tides
Location: Pacific coast
of U.S.
Coastal Tidal Currents
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Flood current- water rushes into a bay/river with
an incoming tide
Ebb current- water drains out of a bay /river
because a low tide is approaching
High slack water- peak of high tide (no currents)
Low slack water- peak of low tide
Waves
Parts of a Wave (draw figure)
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frequency=
1/period
wave speed=
wavelength/
period
Types of Waves
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Tidal Bores- wall of water that moves up
certain low-lying rivers due to an incoming
tide (tidal wave)
Shallow water- touch the ocean floor which
interfers with the wave’s orbital motion
(controlled by water depth, ex: tsunami)
Deep water- no interference with ocean
bottom (wind generated, open ocean and
controlled by wave length)
Rogue
Types of Breakers
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Spilling- turbulent mass of air and water that
runs down the front slope of the wave as it
breaks from a gradual beach slope
Plunging- curling crest that moves over an air
pocket from steep beach slope (best surfing)
Surging- wave energy is compressed into a
shorter distance from an abrupt beach slope
What factor does not affect
deepwater wave production?
A. Wind speed
B. Pull of moon
C. Fetch (distance over which wind blows)
D. Duration of the wind blowing
Answer is : B
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Shallow water waves can be tsunamis or tide
waves
Whereas deep water waves are solely
caused by the fetch, wind speed and duration
Movement of Water in a Wave
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A wave is the transmission of
energy through matter.
•As the wave approaches,
individual particles of water
move in circular patterns as
the wave’s energy moves
through the water
•Orbital motion
Tsunamis
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Sometimes reaching heights of 40 meters
(120 ft.) or more, tsunamis are the most
dramatic and destructive of waves.
Seismic Sea waves
Cause of Tsunamis
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A tsunami results from
sudden water
displacement caused by:
 Landslide
 Iceberg falling into the
sea from a glacier
 Undersea volcanoes
 Earthquake
 Also called tidal waves
 Shallow water waves,
fast moving
Hurricanes
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Hurricanes generally form at the tail of the arrow
and typically track following the arrow to its
arrowhead.
Hurricanes form and intensify over oceanic
regions. They require sea-surface temperatures
of at least 26°C (80°F) and the influence of the
earth’s rotation to initiate a spinning circulation
(Coriolis effect).
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The Atlantic hurricane season is from June 1
to November 30, but most hurricanes occur
during the fall months. The Eastern Pacific
hurricane season is from May 15 to
November 30.
Day 2: Chapter 6 in book
1. Bellwork: Read pgs. 180-181
Give 5 facts from reading
2. Draw figure 6.11 pg. 171
 Define all terms on figure
3. Define: weather, climate, warm front, cold front,
tropical cyclone, hurricane, typhoon, cyclone,
eye of hurricane, storm surge, sea ice, ice bergs,
pancake ice, ice floes, shelf ice
4. Explain how El Nino affects the Pacific Ocean
surface currents? Pg. 218
5. Review Questions pg. 191 #12-14
 Write out question and answer
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Day 3
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Thermodynamics
 Open system- energy & mass flows (ex:
open ocean, human body, saucepan no
lid)
 Closed system- heat & work can be
exchanged across boundary (ex: Earth,
terrarium, saucepan with lide)
 Isolated- same mass, no exchange (ex:
physical universe or thermos)