DE (W10)

• there are three major ocean basins: the Pacific, Atlantic and Indian ocean
• the ocean covers 70% of Earth’s surface
• the ocean has an average depth of 4km
• drivers of ocean circulation include: winds, Earth’s rotation (Coriolis) and density (buoyancy) differences
• coastal drivers include: tides and breaking waves
• Wind impacts the <100m of water, exerting forces (drag) on the surface, resulting in surface currents that are about 3-4% of the wind’s speed
• global wind patterns are formed due to changes in density of the atmosphere due to warming occurring near the equator creating convection cells that drives warm air to rise and move towards the poles until it cools, sinks and is pulled back along the surface of the water to the equator.
• the Coriolis (rotation) effect impacts causes moving parcels of water to in the ocean to rotate (differing in direction in the northern and southern hemisphere)
• The Coriolis effect in the atmosphere causes tropical cyclones (SH) and hurricanes (NH) = they are intense low pressure regions in the atmosphere
• global wind patters: easterly trade winds near the equator, mid-latitude westerly winds (40-60 degrees N and S) and patters generated by the Coriolis effect
• Wind/Ocean currents move clockwise in the northern hemisphere and anti-clockwise in the southern hemisphere
• Gyres are the established surface currents that occur due to global wind patterns
• Thermohaline circulation occurs in the ocean due to cooling causing water the sink at the poles and warming at the equator causing water to rise resulting in deep ocean circulation
• Thermohaline is also impacted by the Coriolis effect