ocean3 homework
2. What roles do friction, gravity and the Coriolis effect play in generating surface ocean currents?
Page 251 the Coriolis effect influences any moving mass as long as it moves. So water gyre might be exposed to curve to the center of North Atlantic and stop. Page 250- the primary force responsible for surface currents is wind. -they are global patterns within latitude bands. Page 251- water pressure is higher on the piled up side and the force of gravity pulls water down the slope.against the pressure gradient.
week 7 question 1: Explain the concept of orbital wave -the transfer of energy from water molecure to water molecure moves in thi shape/path/near at the surface. -Assume deep water.
page 284- The transfer of energy from water particle to water particle in these circular paths, or orbits transmit wave energy across the ocean surface and causes the wave to move. - a wave in which particles of the medium water move in closed circles as the waves passes.
week 7 13] Refer to this website for the next question: hweek ttp://www.nhc.noaa.gov/surge/. -What is responsible for the greatest share of storm surge: L pressure or storm winds? Explain. -How does the slope of the continental shelf related to storm surge? What slope configuration is MOST likely to be associated with a high storm surge?
- water being forced toward the shore by the wind. --- Storm surge is produced by water being pushed toward the shore by the force of the winds moving cyclonically around the storm. The impact on surge of the low pressure associated with intense storms is minimal in comparison to the water being forced toward the shore by the wind. - Other factors which can impact storm surge are the width and slope of the continental shelf. A shallow slope will potentially produce a greater storm surge than a steep shelf. - For example, a Category 4 storm hitting the Louisiana coastline, which has a very wide and shallow continental shelf, may produce a 20-foot storm surge, while the same hurricane in a place like Miami Beach, Florida, where the continental shelf drops off very quickly, might see an 8 or 9-foot surge. More information regarding storm surge impacts and their associated generalizations can be found in the FAQ section. -Adding to the destructive power of surge, battering waves may increase damage to buildings directly along the coast. Water weighs approximately 1,700 pounds per cubic yard; extended pounding by frequent waves can demolish any structure not specifically designed to withstand such forces. The two elements work together to increase the impact on land because the surge makes it possible for waves to extend inland.
7. compare and contrast western and eastern boundary in terms of source region, prevailing direction o fmovement, temo charachsitics, relative depth (shallow or deeo) relative width (broad narrow) relative speed (fast or slow) what are the dominant W and E boundary currents in the N PACIFIC AND n ATlantic.
------Western Boundary Currents---- Western ocean basins & off East coast of continents •Narrow, fast and deep• More so than Eastern Boundary Currents•Extremely large volumes of water transported •Move warm water poleward •N Atlantic: Gulf Stream; S Atlantic: Brazil current •N Pacific: Kuroshio; S Pacific: E Australian current •Indian: Agulhas -WBCs can have distinct boundaries•Eddies (circular motions) form along the edges of the current •Where fast-flowing water meets quiet water •Gulf Stream keeps W Europe warmer •Hurricanes ---- eastern boundaries--- Eastern ocean basins & off West coast of continents •Broad, shallow and slower than WBCs •Transport less water and have fewer eddies than WBCs •Move cold water toward equator •N Atlantic: Canary; S Atlantic: Benguela •N Pacific: California ; S Pacific: Peru (Humboldt) •Indian: W Australian Cold currents affect climate •Stable conditions exist •H pressure & subsidence •Cold water chills air •Cooled air more dense & resists upward motion •Movie industry in CA •Driest: Atacama (Peru)•Namib (Benguela) •Contrast of ocean & desert
2] In general, what is the wavelength of tides? (use units of miles)
-tides are an extreme example of shallow-water waves. wavelength of the tidal wave is 20,000 kilometers (12,400 miles) compared to an average ocean depth of 4 kilometer. A shallow wave is one traveling in water depths less than 1/20 of its wavelength; b
12. explain el nino and how it alters normal wind and ocean currents circulation. -what were the 2 strongest el nino events in the past 50 years?
El Nino :•STH cell weakens & can be replaced by Low •Trades weaken and reverse •Warm water flows eastward across Pacific •Increased convection in E Pacific (normally stable) •H pressure & subsidence in W Pacific (dry conditions) two events-- page 267-- occurred between 1982-1983 and 1997-1998.
At a minimum, be sure to include the following information in your answer: -date of occurrence, - how the tsunami was triggered (earthquake etc.), -how many people died (if available), -whether a warning network was in place, if the area is still vulnerable (and why).
March 27, 1964Alaska Earthquake and Tsunami A 9.2 magnitude earthquake devastated the western Northern American coastline trigged the tsunami without warning. The event took 139 lives and 124 were directly caused by the tsunamis. The earthquake and ensuing tsunamis caused about $2.3 billion of damage. The aftermath of the Great Alaska Earthquake led to the creation of the NOAA Tsunami Warning Centers, -According to National Centers for Environment Information
3. What is an ocean gyre? What is the Greek orgin of this world and what does it mean? DESCRIBE THE FLOW of the North Atlantic gyre given in detail. What are the names of the currents involved? What is their direction? ( n to s)
Page 251 — Gyre- this flow around the periphery of an ocean basin are called a gyre. Look at example 9.2 -Greek orginal GYROS" A CIRCLE" -example of the flow 9.3 - is a series of four interconnecting currents with different flow characteristics and temperatures. 4 CURRENTS= GULF STREAM, NORTH ATLANTIC CURRENT, CANARY CURRENT, NORTH EQUATORIAL CURRENTS Circular pattern of surface currents in ocean basins• Periphery of ocean basin• Balanced along Met. Equator & don't converge•Flow continuously •CW in N Hem; CCW in S Hem •Made up of individual surface currents •Garbage patches Western ocean basins & off East coast of continents •Narrow, fast and deep •Moreso than Eastern Boundary Currents •Extremely large volumes of water transported •Move warm water poleward •N Atlantic: Gulf Stream; S Atlantic: Brazil current •N Pacific: Kuroshio; S Pacific: E Australian current•Indian: Agulhas
4) What is Ekman transport? Explain the process involved in the woman spiral? Does the water actually spiral? Explain? What is the NET direction of Emmanuel transport relative to wind in the n Hemisphere. Is it the same in the S hemisphere?
Page 252- because of the frictional losses, each lower layer also moves more slowly then the layer above. -THe world spiral is somewhat misleading, the water itself does not spiral downward in a whirlpole-like motion like water going down the drain. Rather, the spiral is a way of conceptulizing the horizontal movements in layered water column each moving slightly different horizontal direction. Ekman Spiral• Transport of water: surface & depth•Top layer of water flows ~45 ̊ to the right of wind direction (N Hem.)•Left in S Hem. •Successively deeper layers deflected to right (N Hem.) of the layer above •To left in S Hem.•With depth: slower due to friction •At friction depth: water flows in direction opposite to that of surface -Net transport of water•Sum of all vectors of Ekman Spiral •90 degrees to right of wind direction (N Hem.)•90 degrees to left in S Hem.•Idealized model -Real ocean does not always match the idealized conditions •Shallow water: full spiral can't develop•Angle between wind direction & surface water flow may be < 15 ̊ •Deeper water: angle can be 45 ̊ •Stable Pycnocline can inhibit transfer of energy to deeper water •Wind-driven currents don't always transfer energy to depths •In nature, Ekman transport is rarely 90 ̊•In most cases barely reaches 45 ̊ -Currents flow along periphery of ocean basins•Boundary currents'•'Dome' of water: result of Ekman Transport •Water flows around 'dome' •Balanced between Coriolis and downhill pressure gradient •Geostrophic flow
week 7 q5: in general, what conditions must be exceeded for a whitecap to form? (ratio of wave to horizontal distance)
Whitecap is a physical property of surface water. It can be observed in a sea or lake. But the profound effect is seen in a sea. A water body forms a crest of foam over it's surface called as whitecap. It is formed by the ripples of waves that are produced by the wind. The stronger the wind the more it exert force to the surface layer of water.
week7q8: a freakishly large and unexpected composite wave is also known as a __Wave.
a rogue wave
8. know the currents of the world figure 9.8and be able to identify a given current by the name and location and understand the characteristics of the location
page 225 for chart class notes-- transverse Currents •E to W currents or W to E current •Link eastern and western boundary currents •Complete circuit for an oceanic gyre •Trade winds: shallow and broad tropical E-W currents •N and S equatorial currents•Flow unimpeded for vast distances! •Westerlies: wider and slower mid-latitude W to E currents •N Pacific and N Atlantic currents •Impeded flow in N Hem. but unobstructed in S Hem.
6.what is geostrophic gyre? what forces are in balance? do ocean circulations meet or balance on the geographical or meteorological equator? explain?
page 253- Gyres in the balance between pressure gradient and the Coriolis effect are called geostrophic gyres. and their currents are geostrophic currents. because of the patterns of driving winds and the present positions of continents the gyre are largely independent of the one another in each hemisphere. -the junction, lies a few degrees north of the geographical equator, at the meteorological equator.
9. what are the specifics of the Gulf Stream in terms of average speed, depth, miles, distance the water can move in a day, and flow. what does a Sverdrup unit equal?
page 254- the Gulf Stream moves at an average speed of 2 meters per second which equals 5 miles per hour to a depth of more than 450 meters (1500 feet)/ water in the gulf stream can move 160 kilometers (100 miles) a day. it averages width os about 70 kilometers (43 miles) the unit used to express volume transport in ocean is called a Sverdrup. it equals 1 million cubic meters per second. the gulf stream flow is at least 55sv ( 55 million meters per second)
10. ocean currents can affect the weather and the climate of a location. explain in detail western Europe (Dublin Ireland) and the western us (San Francisco,ca) as examples. -what currents are involved in both locations? -how is climate affected by these currents?
page 261 Along with the winds, surface currents distribute tropical heat worldwide. -warm water flows to higher latitudes, transfers heat to the air and cools, moves back to low lattitudes and aborbs heat again:then the cycle repeats. - in the winter again, Dublin, are bathed with eastward-moving air only recentely in contact with the realtively warm north atlantic current. WESTERN US The California current, carrying cold water from the north, comes close to the coast of SAN FRAN, Wind approaching the caost loses heat to the cold sea and comes ashore in to chill SAN FRAN.
11. -what is upwelling? -how does it occur? -use California for an example -why is upwelling important for marine life?
page 261- Wind blowing parallel to shore or offshore can cause coastal upwelling. -the firction of wind blowing along the Coriolis effect deflects it to the right in the northern hemisphere. and the resultant is in the Ekman moves off shore. California example 9.20 page 264 -Wind blowing from the north along the California coast causes offshore movement of surface water and substequent coastal upswelling. the overally. air becomes chilled which is why san fran is so foggy and has cool summers.
13. thermohaline currents are driven by
page 271 class notes Ocean conveyor belt that cycles water•1) Antarctic Bottom Water: most dense on Earth•Most forms in winter: SE of tip of S America •Salt held between pure water crystals is squeezed out •Very cold, salty water sinks to bottom (downwelling) •Moves northward at a slow pace •Pacific: could take 1000 years to reach equator! 2) N. Atlantic Deep Water (NADW) •Gulf Stream delivers warm, salty water to N Atlantic•Increase in density when warm, salty water cools •Also, seawater beneath ice •Downwelling of high density water near Iceland •Mass is replaced by water from Gulf Stream •Zones of upwelling keep conveyor belt circulations going •Steady supply of water •Sinking of dense water is offset by upwelling in warmer areas •This upwelled water flows (at the surface) to the Poles & the cycle continues •If there were no upwelling, global thermocline would descend & circulation would weaken (or possibly shut down) Warming climate: large freshwater pulses from melting polar ice •Freshwater is less dense •Shut down thermohaline circulation •Happened at end of last Ice Age •Thermohaline circulation & Gulf stream shut down •Abrupt and renewed cooling for 1000 yrs in N Hem •Cooling of 8-15 ̊C: Younger Dryas
13 explain how the n.atlantic deep water circulation is set in motion. -where is the NADW circulation initiated (near Ireland, canary island, Iceland, newfoundland) -why /how is the circulation generated?
page 273 -these channels allow the cold, dense water formed in the arctic to flow into the north atlantic. -forms when the relatively warm and salty north atlantic ocean cools as cold winds form nothern Canada sweeps over it. exposed to the chilled air, water at the latitude of Iceland releases heat,cools from 10 to 2 and sinks. gulf stream water that sinks in the north is replaced by warm water flowing clockwise alng the us east coast aling the use east coast in the north atlantic gyre.
week 7: q3 what is a deep water wave? a wind wave with a wavelength of 100 meters will act as a deep water wave if its passing through water at least ______ deep. - if this wave moves into shallower water, what will happen to the orbital motion in that wave?
page 287 when waves moving through water deeper than half their wavelength. 100 meters = 50 meters -the orbits of water molecules in waves moving through shallow water are flattened by the proximity of the bottom.
week 7:q4 there are 3 factors that lead to the development of a wind wave. what are they? what is meant by the word fetch?
page 289- wind waves are gravity waves formed by the transfer of the wind energy to the water. -most winds waves are less than 3 meters high, wavelengths from 60 to 150 meters aND MOST COMMON in the open ocean. FETCH= PAGE 576 GLOSSERY---THE UNINTERRUPTED DISTANCE over which the wind blows without significant change in direction, a factor in wind wave development.
week 7 q6: Explain the concept of fully developed sea. what coniditons would be necessary for the seas and average wave ehight of 13.6 feet. with an average wave period of nearly 9 seconds)
page 292 a strong wind must blow continuously in one direction for nearly 3 days for the largest waves to develope. it's the maximum wave size possible for a wind of strenght , durton and fetch.
week 7 q7: what are the two types of wave interference? name and describe them? Assume that you are a surfer in search of the big one, what conditions would a giant wave develop? under what conditions would a giant wave develop? under what conditions would a giant wave develop? winder what conditions would a giant wave develop? Under what conditions would you swim out catch this wave.
page 295- the cancellation effect of subtraction is termed destructive interference not because of harm to lives or property but because wave interference destroys or cancles waves. constructive interference is the additive formation of large crest of deep troughs the size of which exceeds the soze of each participating wave.
week7q10. - what is a wave refraction. under what conditions does wave refraction occur?
page 299 the slowing and bending waves in shallow water. the waves break in a line almost parallel to the shore
week7q12: what combination of factors can make for an unusual high storm? The deadlist storm surge occurred in 1970 in this nation. _________ How many people have died because of the event? how high was the storm surge in this event? how how was storm surge?
page 303- the most important factor is the strength of the storm generating the surge. the low atmosphere pressure associated with a great storm with draw the ocean surface onto board dome as much as 1 meter higher than average sea level. -The storm november 1970 in banglasdesh killing 1783 people. - 9 meters (30 feet) high
week7 q11: sometimes a tsunami or rogue wave called a tidal wave. Why is the term tidal wave a misnomer? why is the term incoorect?
page 306 long wavelength shallow water progressive waves by the rapid displacement of ocean water. -tidal wave 301- misname any large wave regarldless of its orgins.
16] Is a tsunami a shallow or deep water wave? Explain.
page 306- longwave shallow water progressive waves https://www.infoplease.com/world/earthquakes/... What is a tsunami? The phenomenon we call tsunami is a series of large waves of extremely long wavelength and period usually generated by a violent, impulsive undersea disturbance or activity near the coast or in the ocean.
14] The word 'tsunami' is a Japanese word meaning __________________. Under what conditions can a tsunami form? What two major tsunami events occurred since 2000? Where were the main devastating effects located (name the countries involved)? How were these 2 tsunami events generated? How many deaths were attributed to each of these events?
page 306- long-wave shallow water progressive waves caused by the rapid displacement of ocean water. -term - harbor * wave -caused by landslides, iceburgs falling from glaciers., volcanic eruptions, asteroid impacts, and other placements of the water surface. -march 11 2011 a seismic sea wave struck northern japan. 20 feet in some places. -sumatra in the indian ocean December 2004 10 meters -moved gapan 4 meters closed to the us both comboned took the lives f nearly a 3rd of a million people.
15] What is the typical wavelength of a tsunami? In the open ocean, tsunami can move at the speed of a jet. What happens when tsunami approach land and move onshore? Be sure to talk about changing water depths, wave height and "run-up" in your answer.
page 308 once a tsunami is generated its steepness is extremely low. page 308 the combination of wave height and run up (the distance the waves moves ashore) determines a tsunami lethality. -A tsunami may come onshore like a fast-rising flood or a wall of turbulent water, and a large tsunami can flood low-lying coastal areas more than a mile inland. Rushing water from waves, floods, and rivers is incredibly powerful. Just six inches of fast-moving water can knock adults off their feet, and twelve inches can carry away a small car.
3] How are tides different from other types of waves we've learned about (wind waves, tsunami etc.)?
page 317-- gravity tends to pull earth and the moon toward each other but inertia the tendency of moving objects to continue in a straight line keeps them apart. earth and moon don't smach into each other because they are stable in prbit their mutual; gravity pull is offset by inertia/
Week 6: Ocean Circulations (Chapter 9) 1] 1. -Surface ocean currents are driven by _______________________. -What % of water in the global ocean is involved in these surface currents? Surface currents are generally concentrated in the upper ______ feet of the ocean.
page250 *Surface ocean currents are driven by 10% -About 10 percent of the water in the world ocean is involved in surface currents. -they are currents with water flowing horizontally in the uppermost 400 meters of the oceans surface, driven by mainly by wind friction..
week 7 question 2- Define the terms progressive wave wave crest wave trough wave height wavelengh wave period wave frequency
progressive wave (282)the wave moves forward. wave trough -the valley between wave crest below average water level. wave crest- is the highest part of the wave above average water level wave height-Is the vertical distance between a wave crest and adjacent trough. wavelength- the horizontal distance between two successive crest or troughs. wave period- the time it takes for a wave to move a distance of one wavelengh wave frequency- Is the numberof waves passing a fixed point per second.
1] Are tides considered 'deep' or 'shallow' water waves?
tides are periodic, short-term changes in the height of the ocean surface at a particular places caused by combo of he gravitational force of the moon and sun. -Tides and Tsunamis are shallow water waves, even in the deep ocean
