Lecture 4: Waves

• Seawater is selectively transparent to light
• Light attenuation with depth depends on atmospheric conditions, angle of light, wavelength, and turbidity
• Deep water waves have no net horizontal or vertical movement, have orbital motion, and propagation of energy
• Shallow water waves have plunging waves and spilling waves
• Plunging waves are found at the steep beach slope and is where the crest curls and outruns the wave, creating a sudden loss of energy
• Spilling waves are found at the flat beach slope and have a gradual loss of energy
• Tsunamis are waves with long wavelengths, long periods, and low hight formed from sudden movements of earth's crust
• Internal waves are waves that oscillate within, as opposed to on the surface of, a fluid medium
• Tides are specialized waves that are influenced by gravitational pull of the moon and sun
• Neap tides are the lowest of tides and occur when the moon is at its furthest point from the earth
• Spring tides are the highest of tides, when the moon is closest to the earth.
• Diurnal tides are one low and one high tide a day
• Semidiurnal tides are two high and two low tides per day
• Mixed tides have a higher high tide and a lower low tide with high and low tides
• Surface currents are caused by winds and are driven by the Coriolis effect
• The Coriolis Effects is the deflection of movement due to the spinning of the Earth on its axis
• The Ekman Spiral is when surface waters are moved by the wind and drag deeper water layers with them
• Planetary winds are caused by unequal heating of the Earth
• 3 major wind belts include the trade winds, westerlies, and polar easterlies
• Western Boundary Currents are where warm water moves towards the poles quickly
• Eastern Boundary Currents are where cold water moves towards the equator slowly
• The Ocean Conveyor Belt is a worldwide system of rising and sinking water masses driven by temperature and salinity differences
• Upwelling is the upward movement of water, allowing for the mixing of cold, nutrient-rich bottom water with warmer surface waters
• Downwelling is when dense surface water sink at colder latitudes
• Equatorial upwelling is when currents on either side of the equator pull surface water away and is replaced with deep waters
• Coastal upwelling is when winds blow parallel to the coast and produce surface currents that move offshore, allowing deeper water to rise
• Two areas of wind-driven upwelling are the Humbolt Current and the Benguela Current