Honors Marine Science Unit 2 Study Guide Flashcards

Flashcards covering key vocabulary terms and definitions regarding ocean currents, wave dynamics, and tidal phenomena from Unit 2.

Currents

Continuous directed movement of ocean water generated by forces acting on the water.

Current Primary Forces

Forces that start the water’s movement and determine velocity/speed, including wind, temperature, and density.

Current Secondary Forces

Forces that influence the direction and nature (wideness/narrowness) of the flow, including the Coriolis Effect, gravity, friction, and ocean floor features.

Gyre

The circular pattern the water makes when moving in currents; continuous circles that feature multiple currents and are bordered by continents.

Western Boundary Currents (WBC)

Fast, very deep, and narrow currents located on the western side of the gyre (eastern side of the continent) that carry warm water.

Charleston Bump

An ocean floor structure that influences the Gulf Stream by impacting its direction.

Eddies

Pockets of water trapped in other temperatures that can be up to $1000\text{ km}$ wide, last for $3\text{ years}$, and are deep, common, and important.

Cold Core Eddies

Pockets of cold water that spin counterclockwise and travel south, forming where Western Boundary Currents meander south.

Warm Core Eddies

Pockets of warm water that spin clockwise and travel north, forming where Western Boundary Currents meander north.

Eastern Boundary Currents

Slow, shallow, wide, and cool currents located on the eastern side of the gyre (western side of the continent).

Transverse Currents

Generic term for equatorial and polar currents that travel across the ocean and change temperatures as they go.

West Wind Drift

Also known as the Antarctic Circumpolar Current; one continuous current moving around Antarctica that creates a temperature barrier.

Equatorial Counter Current

A current formed due to lack of wind in the ITCZ that pushes water not picked up by gyres back in the opposite direction.

Undercurrents

Water pushed down beneath the Equatorial Counter Current that travels parallel to it.

Upwelling

The upward movement of cold ocean water that holds oxygen and nutrients to the surface.

Downwelling

The downward movement of water that creates an undercurrent and fuels upwelling.

El Nino

A natural event occurring when upwelling stops in California and Mexico because the ITCZ moves south.

ENSO Event

El Nino Southern Oscillation event; the same phenomenon as El Nino.

La Nina

The condition opposite of El Nino, occurring when upwelling is present in California and Mexico.

Deep Currents

Also known as thermohaline circulation; density-based circulation making up $900\text{ percent}$ (or $90\text{ percent}$) of the ocean under the pycnocline.

Global Ocean Conveyor Belt

The system of slow-moving deep ocean currents that slowly rise, join upwelling, and deliver oxygen and nutrients around the world.

Waves

A disturbance caused by the movement of energy through a liquid where energy moves horizontally while water moves up and down.

Wave Crest

The highest point of a wave above the average water level.

Trough

The lowest point of a wave below the average water level.

Amplitude

The distance of water from the midpoint to the crest or trough.

Height

The distance from the crest to the trough of a wave.

Length

Also known as wavelength; the distance from crest to crest or trough to trough.

Period

The time it takes for one wavelength to pass a point.

Frequency

The number of waves that pass a point in a given amount of time.

Orbital Waves

Typical ocean waves where water particles move in circular orbits.

Disturbing Forces

Forces that start a wave by disturbing the surface of the water, such as wind, density, seismic activity, storms, and the moon and sun.

Restoring Forces

Forces that attempt to restore the ocean surface to its original level, such as surface tension and gravity.

Capillary Waves

Tiny waves formed on the surface of water.

Progressive Waves

Waves that move forward across the water surface.

Standing Wave

Waves that do not move forward, typically occurring in small enclosed areas.

Deep Water Waves

Waves occurring in water deeper than $\frac{1}{2}$ of a wavelength that do not interact with the ocean floor.

Transitional Waves

Waves occurring in water depth between $\frac{1}{2}$ and $\frac{1}{20}$ of a wavelength.

Shallow Water Waves

Waves occurring in water depth less than $\frac{1}{20}$ of a wavelength where waves start to break.

Surf

A turbulent mass of agitated water rushing to shore during a wave break.

Surf Zone

The area between where the waves start to break and the shore.

Fetch

The distance that wind blows away from a storm to create waves.

Free Waves

Waves that break free from the force that creates them.

Forced Wave

Waves that do not break free from the force that creates them, such as tidal waves.

Rogue Wave

Waves that grow very large during storms due to constructive interference.

Internal Waves

Deep water waves driven by differences in density between water layers.

Seiches

Standing waves caused by storms or seismic activity that move at a specific frequency.

Tsunami

A long-wavelength, shallow water, progressive wave caused by seismic activity.

Plunging Breaks

Stereotypical surfer waves featuring curls that often form on steep beaches.

Spilling Breaks

Waves that break without curling, such as those found in Charleston.

Collapsing Breaks

A cross between plunging and spilling waves where the water collapses and the crest does not break.

Surging Breaks

Waves that go directly in and out without breaking normally, such as storm surges.

Constructive Interference

When the crests and troughs of two waves align at the same point, combining to create a much larger wave.

Destructive Interference

When the crests and troughs of two waves combine at different points to cancel each other out.

Tide

Periodic short-term changes in the height of the ocean’s surface caused by the sun and moon.

Lunar Tide

The component of the tide created by the moon that drives high tide.

Solar Tide

The component of the tide created by the sun that works alongside or against the moon based on moon phases.

Spring Tide

Tides occurring during new and full moon phases where lunar and solar tides work together, creating higher high tides and lower low tides.

Neap Tide

Tides occurring during half/quarter moon phases where lunar and solar tides work against each other, creating smaller differences between high and low tides.

Semidiurnal Tide

A tidal pattern with $2$ high tides and $2$ low tides each day, each at the same amplitude.

Diurnal Tide

A tidal pattern with only $1$ high tide and $1$ low tide each day.

Mixed Tide

A tidal pattern with $2$ high tides and $2$ low tides each day at different amplitudes.

Tidal Datum

The average water level against which high and low tides are compared during measurement.

Meteorological Tide

Tides impacted by weather events like storms, commonly referred to as king tides.

Tidal Bore

The scientific name for a true tidal wave, occurring when an incoming tide brings a wave with it.

Flood Current

A tidal current occurring when the tide is coming in and bringing water with it.

Ebb Current

A tidal current occurring when the tide is going out and taking water with it.

Slack Water

The pause in tidal currents occurring during high and low tide.

Maelstrom

Whirlpools formed when two tidal currents pass each other and create a rotating vortex.