Circulation and Tides
What causes tsunamis? How are they different from typical waves?
Causes - earthquakes, volcanoes, landslides Differences: Speed - Faster Wavelength - Longer Height (open ocean) - Lower
Explain thermohaline circulation and the formation of deep bottom water. What is the great ocean conveyor?
Component of general oceanic circulation controlled by temperature and salinity. It continually replaces seawater at depth with water from the surface and slowly replaces surface water elsewhere with water rising from deeper depths.
What is the main driving force of the oceans surface currents?
Coriolis effect and wind
What causes tides?
Generated by the gravitational pull of the moon (main) and the sun and the rotation of the Earth
What are gyres? What are the major gyres? How do they flow in northern and southern hemispheres? Why do they flow in opposite directions?
Gyre - large ocean current Types: Clockwise currents - N. Pacific, S. Pacific, and N. Atlantic Counterclockwise currents - S. Atlantic and Indian
Describe the anatomy of wind-driven winds.
Highest point - crest lowest point - trough wave height between waves - wavelength
Define the difference between main and seasonal thermoclines.
Main occur permanently while seasonal only occur during a time of the year where the water is warmer longer
What are the major surface wind bands? What are doldrums and horse latitudes?
Major - trade winds, westerlies, polar easterlies doldrums - belt near the equator where ships become stuck on windless waters horse latitudes - a belt of calm air and sea occurring in both the northern and southern hemispheres between the trade winds and the westerlies.
What impact does the Coriolis effect have on the movement of air and water in the Northern and Southern hemispheres?
Northern - right Southern - left
What are semidiurnal, mixed semidiurnal, and diurnal tides? Which is more common?
Semidiurnal (common) - Normal tides which consist of 2 high, 2 low Mixed semidiurnal - Two differ types of tides in terms of height Diurnal - Only 1 high and 1 low wave (Antarctica)
What happens as waves move into shallow waters?
They begin to be affected by bottom floor. Half wavelengths "feel" the bottom floor
How do water molecules move within a wave?
They move in a circular motion, along the wave
What are spring and neap tides? What causes these tides and when in the lunar cycle do they occur?
Types of waves that occur every month depending on the alignment of Earth relative to the moon and sun Spring tides (positive alignment) - gravitational forces add together to give higher tidal ranges than normal Occur during new and full moons Neap tides (negative alignment) - gravitational forces pull away from each other creating lower than normal range Occur during the 1st and 3rd quarter moon
What is upwelling and downwelling? Major upwelling?
Upwelling - surface waters are are moving away from an area or coast Downwelling - surface waters driven together by wind or against coast Major - Africa
What is Ekman Transport?
Water does not travel parallel with wind; instead it travels in a spiral 45 degrees with respect to the wind It has more effect on the surface/upper levels, than it does on the deep bottom
How do seasonal thermoclines develop?
When there is no mixing of water temperature during the warmer months
What are thermoclines and haloclines?
thermoclines - temperature haloclines - salinity
