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Marine Physics. Chapters 6-9 JUST COPY WHAT IS UNDERLINED!!!!!!. Influence of Currents on Climate. Pgs. Because of the area and thermal properties of the ocean it dramatically influences global weather and climate patterns.
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Marine Physics Chapters 6-9 JUST COPY WHAT IS UNDERLINED!!!!!!
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 currents- carries 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 • Florida and N. Europe- milder winters
California Current • S. California- mild climate due to the moderating effects of the Pacific Ocean • 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 • 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: • Trade winds • Westerlies • Polar Easterlies
#2 Land Masses • interrupt the flow of ocean currents creating closed circular current systems called gyres. • Forces currents to turn
#3 Coriolis Effect • 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 • 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 • 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 • Earth’s rotation-adds an apparent sideways motion to objects moving over the Earth’s surface. Pilots need to correct their flight path based on the earth rotating under the airplane, which is the Coriolis effect.
Tides Pgs 10-3 to 10-24
What are Tides? • Daily variations in the ocean’s level • The mean average tide occurs later each day by 50 min • HighLow =6 hours 13 min. • HighHigh=12 hours 25 min. • most noticeable at the shore, but affect the entire ocean.
Cause of Tides • 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 • 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
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 • Diurnal tide • Single high and low tide daily • Location: Gulf of Mexico • Semidiurnal Tide • Two “equal” high and low tides • Location: east coast of U.S. • Mixed Tide • Two unequal high and low tides • Location: Pacific coast of U.S.
Coastal Tidal Currents • 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
Parts of a Wave (draw figure) • frequency= 1/period wave speed= wavelength/ period
Types of Waves • 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 • 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 • 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 • 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 • 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 • 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 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).
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
Day 3 • 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)