Bellwork 1/29 Based on your Google Earth investigation, what do you notice about the circulation of currents in the Northern & Southern hemispheres? What causes ocean currents? How do currents affect weather/climate?

Bellwork 1/20 Which two techniques did you model to figure out what the bottom of your “ocean” looked like? What are some strengths and weaknesses of each type of map?

Go Over Bathymetry Lab

Safety Procedures

This is a Weather class… Why do we care about what the bottom of the ocean looks like?? Underwater structures affect the flow of ocean currents Ocean currents drive air flow and weather patterns!

Two Types of Ocean Circulation: Surface Circulation -Gyres Deep Ocean Circulation -Thermohaline Currents

1. Surface Circulation Develop from friction between the ocean and the wind Can be seasonal or permanent

Ocean Basin Circulation Patterns: Gyres circular moving current systems Individual currents can be warm or cold Dominant surface pattern in the oceans S. Hemisphere = counterclockwise rotation N. Hemisphere = clockwise rotation

Something to note… Surface currents vary because of wind. So…they won’t always look as “pretty” or defined as they do in a textbook. From the textbook From real data

Gyres & their currents are pretty predictable & permanent in terms of their direction and temperature (warm or cold) Why might understanding that be useful to humans? How could we use gyres/current patterns? Travel patterns Animal migrations Weather/storm predictions Treating/containing chemical or oil spills

Unfortunate Affect of Gyres… “Great Pacific Garbage Patch”

Gulf Stream: best known and most studied of the ocean currents Part of the North Atlantic Gyre flows northward along the east coast of the United States carries warm water from the Gulf of Mexico

2. Deep Ocean Circulation accounts for thorough mixing of deep water masses formed by differences in salinity & temperature “thermohaline” currents Begin forming in high latitudes as cold, salty water sinks

We will dive into the “how’s & why’s” of Deep Ocean Circulation next class. Salinity lab

Ocean Currents and Climate Transfers heat from low latitudes to high latitudes (and vice versa) Keeps most of western Europe warmer than expected for its latitude Maintains Earth’s heat balance about ¼ of heat transfer is via oceans

Ocean Current Activity Using GoogleEarth to observe surface currents

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