← Tides & Currents: Motion in the Ocean
Flashcards
Tides & Currents: Motion in the Ocean
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Tides & Currents: Motion in the Ocean — Flashcards
| Front | Back |
|---|---|
| What is CO-OPS? | NOAA's Center for Operational Oceanographic Products and Services; collects and distributes oceanographic observations and predictions (water levels, coastal currents, tides) to ensure safe, efficient, environmentally sound maritime transportation. |
| What is PORTS®? | Physical Oceanographic Real-Time Systems—a national network managed by CO-OPS in major U.S. harbors that provides real-time water levels, currents, air gap, weather data, and other oceanographic info to help mariners avoid groundings and collisions. |
| What is "air gap" in the context of PORTS®? | The clearance between the water surface and the bottom of a bridge. |
| What is NODC? | NOAA's National Oceanographic Data Center, which compiles data from ocean current measurement programs using current meters and drifters, and provides access to data on beach temperatures, coastal buoys, global temperature/salinity, etc. |
| What percentage of U.S. cargo is transported by water? | More than 98%. |
| What three factors determine ocean wave height according to the lesson? | Wind speed, duration (length of time wind blows), and fetch (distance over which wind blows). |
| What is "fetch"? | The distance over which the wind blows across open water, which affects the height of resulting waves. |
| Who created the nomogram used to predict wave height from wind conditions? | Charles Bretschneider, in 1952. |
| What is a Sverdrup-Munk-Bretschneider nomogram? | A diagram relating wind speed, fetch length, wind duration, and wave period to predict the resulting wave height. |
| What is the Coriolis Effect/Force? | An apparent force caused by Earth's rotation that deflects moving objects (like ocean currents) to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. |
| What is the "Dishpan Analogy"? | An explanation used in NOAA's Coriolis lesson to illustrate how rotation causes deflection of moving fluids, similar to the Coriolis effect on Earth. |
| What is the magnitude of Coriolis acceleration at the equator? | Zero, since latitude at the equator is zero and the Coriolis formula depends on the sine of latitude. |
| Why is the Coriolis effect negligible on small-scale objects like soccer balls but significant for ocean currents? | Because Coriolis acceleration, though tiny per unit mass, becomes significant when acting on very large masses over very long distances (as with ocean currents), unlike small-scale everyday objects. |
| How is current speed estimated from drifter data? | By dividing the distance traveled between two points by the total time elapsed, yielding speed (e.g., in knots or cm/sec), with direction determined by the path between the points. |
| What formula factors determine the magnitude of Coriolis acceleration? | The sine of the latitude, a constant (1.5 x 10⁻⁴), and the velocity of the moving object/current. |
| What are drifters used for in oceanography? | Instruments deployed in the ocean to track movement over time, allowing scientists to calculate current speed and direction based on distance traveled and time elapsed. |
| What is OSCAR? | NOAA's Ocean Surface Current Analyses – Real Time website, providing global current data obtained through satellite remote sensing. |
| What are the primary causes of ocean currents and waves explored in this lesson? | Wind (driving surface waves and some currents) and the Coriolis Effect (influencing current direction due to Earth's rotation), which together explain how currents vary at different latitudes. |
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