Oceanography Flashcards
Seiche
Seiche
- A seiche is a standing wave oscillating in a body of water. Caused by change in atmospheric presure 2. The largest vertical oscillations are at each end of a body of water with very small oscillations at the “node,” or center point, of the wave of water 3. the time period between the “high” and “low” of a seiche can be as much as four to seven hours
influent / effluent streams
* influent- recharge at bottom of stream where stream channel lies at height above water table (gains water) * effluent- discharge at bottom of stream where stream channel lies below water table (uses up water)
Sound in Ocean
Sound travels in the ocean varies greatly, depending primarily upon water temperature and pressure . While pressure continues to increase as ocean depth increases, the temperature of the ocean only decreases up to a certain point, after which it remains relatively stable
Speed of sound in Ocean
Speed increases as: 1. Temperature increases 2. Salinity increases 3. Pressure (or Depth) increases 4. Low frequency sounds travel farther than high frequency sounds
Thermocline layer
In Ocean, the thermocline is a region characterized by rapid change in temperature and pressure. Below the thermocline “layer,” the temperature remains constant , but pressure continues to increase
Sound Channel
The area in the ocean where sound waves refract up and down is known as the “sound channel
Storm Surge
Series of long waves that are created far from shore in deeper water and intensify as they move closer to land Storm surge is the abnormal rise in seawater level during a storm, measured as the height of the water above the normal predicted astronomical tide
Whale’s sound wave
As the whale’s sound waves travel through the water, their speed decreases with increasing depth (as the temperature drops), causing the sound waves to refract downward Below the thermocline “layer,” the temperature remains constant, but pressure continues to increase. This causes the speed of sound to increase and makes the sound waves refract upward .
Storm Tide
Storm tide is the total observed seawater level during a storm, resulting from the combination of storm surge and the astronomical tide
Waves
Wind Driven/Surface Waves Astronomical Tides Storm Surge Tsunami
Slough
A slough is a swamp or shallow lake system , usually a backwater to a larger body of water
Geodesist
Geodesists measure and monitor the Earth’s size and shape , geodynamic phenomena (e.g., tides and polar motion), and gravity field to determine the exact coordinates of any point on Earth and how that point will move over time
Waves
Waves are created by energy passing through water, causing it to move in a circular motion. Waves transmit energy, not water.
Spring Tide
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Spring Tide
During full or new moons—which occur when the Earth, sun, and moon are nearly in alignment high tides are a little higher and low tides are a little lower than average
Neap Tide
Neap tides, occur twice a month, happen when the sun and moon are at right angles to each other. High tides are a little lower and low tides are a little higher than average
Perigean spring tide
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Perigean spring tide
A perigean spring tide occurs when the moon is either new or full and closest to Earth (3/4 times? a year?) Once every 28 days, the moon reaches a ‘perigee,’ its closest point of approach to the Earth
“Nuisance” flooding
“Nuisance” flooding—flooding that leads to public inconveniences such as road closures—are increasingly common as coastal sea levels rise. Eg: Tide+ Storm Surge+
Nautical mile
A NM = one minute of latitude - 60NM = 1 o at equator A knot is one nautical mile per hour (1 knot = 1.15 mph )
NOAA
12 nm Territorial Sea, 24 nm Contiguous Zone, 200 nm Exclusive Economic Zone (EEZ). Law of the Sea Convention 1958 , 1982
Geoid
* Geoid is a model of global mean sea level that is used to measure precise surface elevations * a surface which defines zero elevation
Salt Marsh
Salt marshes are coastal wetlands that are flooded and drained by salt water brought in by the tides. Salt marshes protect shorelines from erosion by buffering wave action and trapping sediments.
Salt Marsh
Reduce flooding by slowing and absorbing rainwater and protect water quality by filtering runoff, and by metabolizing excess nutrients.
Estuary - River meets sea
Estuaries are among the most productive ecosystems in the world Many animals rely on estuaries for food, places to breed, and migration stopovers.
Estuary vs River Delta
Estuary = where rivers have no Delta. Embayment where ocean advances into the mouth of the river Delta = sandy protection of the river mouth created by the dragging down of sediment by the river flow.
