Quiz 2 Review - Intro to Oceanography

Define coriolis effect

An apparent force that arises because of the earth's spin around its axis. Freely-moving objects are deflected to the right of their direction of motion in the northern hemisphere and to the left of their direction of motion in the southern hemisphere. an effect whereby a mass moving in a rotating system experiences a force (the Coriolis force ) acting perpendicular to the direction of motion and to the axis of rotation. On the earth, the effect tends to deflect moving objects to the right in the northern hemisphere and to the left in the southern and is important in the formation of cyclonic weather systems.

What is the largest current by volume in the ocean? By velocity (speed of water)?

Gulf stream is the fastest, Antarctic circumpolar current (screaming 60's) is the largest Antarctic Circumpolar Current aka the West Wind Drift flows west to east at 50 degrees S Lat, it is driven by the prevailing westerly wind belt and creates super strong wind, only one that completely circumscribes world , it's not super fast, but transports more than any other surface current.

ekman

The ekman spiral is a consequence of the coriolis effect. When the surface water moves by the wind, they drag the deeper layers with them. Each layer of water is moved by friction from the shallower layer and each deeper layer moves more slowly than the layer above it. The deflection of the surface current has an angle of 45°. This creates a spiral called the Ekman spiral. At a depth of 100 meters, the water flows in the opposite direction than the surface current. The net water transport is perpendicular (90°) to the initial wind direction and this is the effective direction of the current flow. The Ekman spiral is a structure of currents or winds near a horizontal boundary in which the flow direction rotates as one moves away from the boundary. It derives its name from the Swedish oceanographer Vagn Walfrid Ekman. Ekman Transport is the net motion of fluid as the result of a balance between Coriolis and turbulent drag forces. In the picture above, the wind blowing North creates a surface stress and a resulting Ekman spiral is found below it in the water column.

how a tsunami forms, seismic sea waves (move 500 miles per hour)

Tsunamis are generated through displacement of the seafloor under water mostly assoc with convergent plate boundaries and most assoc with pacific ocean a series of water waves that travel away from a fault in all directions at high speed ships tend to not notice tsunamis because Tsunamis in deep water have SMALL wave height and LONG wavelength. Why does the wave height of a tsunami increase as the tsunami enters shallow water? In shallow water, the ENERGY of the tsunami must be contained within a SMALLER water column. behave like shallow water waves Also known as seismic sea waves, these are waves caused by the uplift or downdropping of large areas of the seafloor; normally have 5-12 ripples, middle is the strongest. The period varies from 5-60 minutes

Define plunging breakers

Waves that are breaking along the shore and are forming a curling crest over an air pocket

where do we get the largest wind driven waves? Largest wind driven waves tend to be associated with trade winds or westerlies

area of ocean = not doldrums, is it the trade winds or the westerlies?** in book. Trade winds come from the North East, Westerlies come from the West ITS THE WESTERLIES Generally the fastest and deepest ocean currents are the western boundary currents

What is a Gyre?

circular rotation of water on the surface . Large circular moving loops of water driven by major wind belts of the world are gyres (5 subtropical gyres are north pacific, south pacific, north atlantic, and south Atlantic and the indian ocean)bc all at 30 degrees north or south latitude. Each subtropical gyre composed of four main currents that flow into one another. The Four main currents that comprise subtropical gyres are (1) equatorial currents (trade winds blow from SE and NE in hemis and cause these) travel westward along equator and form the equatorial boundary current of the gyre. (2) western boundary currents = Coriolis effect deflects currents away from equator as these currents like the gulf stream and the brazil current - travel along western boundary of ocean basin. (3) northern or southern boundary currents are made by the prevailing westerlies between 30 and 60 latitude and direct ocean surface water in easterly direction (4) eastern boundary currents In summary, within gyres we find that western boundary currents are warm, narrow and fast and eastern boundary currents are cool, slow and broad. Current strength is a bit more complex, but is mainly caused by the Coriolis effect. Recall from your readings the term "western intensification". This term describes the western boundary currents of any given gyre as being fast, narrow and deep currents. This is due to the center of a gyre being slightly offset due to the increasing strength of the Coriolis effect as one moves poleward. Water moving eastward across ocean basins is deflected strongly toward the equator. This creates broader currents on the east side of a gyre and also pushes the center of a gyre slightly to the west. The western boundary currents are narrow and fast because they have less width to travel through due to this west-shifted center - similar to the effect of squeezing a water hose to get a narrower and faster flow of water.

Surface Ocean Circulation, currents on the surface of the ocean

driven primarily by wind, also factor of coriolis effect

Storm surge

is generated usually by what? low pressure systems (Storms) plus wind A storm surge is a rise in sea level that occurs during tropical cyclones, intense storms also known as typhoons or hurricanes. The storms produce strong winds that push the water into shore, which can lead to flooding. ... They form over warm, tropical oceans.

what is a rogue wave?

massive, spontaneous, solitary reach abnormal heights difficult to forecast occur more near weather fronts and downwind of islands occur when normal ocean waves are not usually large individual waves of exceptional height or abnormal shape that are more than twice the average of the highest one third of all the wave heights in a given wave record cause is theorized to be a case of contructive wave interference where multiple waves overlap to produce a large wave (occur freuqently near weather fronts and downwind from islands or shoals)

where is the sargasso sea?

middle of the gulf stream in atlantic ocean, sargasso because of the algae, broken off from shore area because of storms and moved to currents In the North Atlantic Ocean

Deep ocean water, do they have high nutrients and oxygen?

rich in nutrients and oxygen because of downwelling (brings oxygen with lots of oxygen from surface down to deep ocean)

differences between plunging breaker and other breakers

three main types of breakers spilling breaker = a turbulent mass of air and water that runs down the front slope of the wave as it breaks, result from a gently sloped ocean bottom which gradually extracts energy from the wave over an extended distance and produces breakers with low overall energy they have a longer life span, a long but less exciting ride. plunging breaker = curling crest that moves over an air pocket, curling crest occurs because the particles in the crest outrun the wave and nothing beneath to support their motion, they form on moderately steep beach slopes best waves for surfing surging breaker = when ocean bottom has an abrupt slope the wave energy is compressed into a shorter distance and the wave surges forward these waves build up and break right at the shore line, not forsurfing but great for body boarding

What is upwelling?

water dissipates away at the surface and cold nutrient water is able to upwell

What is downwelling?

water gets pushed down (water gets piled up in a place because of winds, it gets pushed down into the water column) Upwelling is the upward movement of cold deep nutrient water to the surface, downwelling is the downward movement of surface water to deeper parts of the ocean. Upwelling brings the cold nutrient water to surface which creates high productivity (abundance of algae) and supports the marine life. Downwelling associated with lower amounts of productivity but carries necessary oxygen to organisms on sea floor. Current divergence happens when water moves away from an area on ocean's surface like the equator and causes upwelling of cold nutrient water (equatorial upwelling) high productivity and some of best fishing grounds bc of this. Current convergence happens when surface waters move towards each other and water stacks up and has no place to go but down and low productivity. Coastal upwelling along west coast of US lots of nutrients and low water temps bc winds from north and Ekman transport moves the coastal water to the right of wind direction so water flows away from shoreline and water rises from below. And if winds from the south Ekman transport causes water to move toward shoreline and downwelling occurs. Upwelling also occurs in high lat regions with no pycnolcines bc allow vertical mixing.

Understand wave height, crest, trough, length,

wave length = distance from one crest to the next or distance from one trough to the next wave height = Crest minus Trough

Do deep ocean water masses have characteristic temperatures and salinity?

yes they do, based on depth of water