Chapter 7-2 Ocean Currents and Climate. What are currents and how do they affect us?. Surface Currents: Are rivers of water moving through the ocean. They travel to a depth of several hundred meters and are driven by winds.
What are currents and how do they affect us? • Surface Currents: Are rivers of water moving through the ocean. • They travel to a depth of several hundred meters and are driven by winds. • Northern hemisphere currents move in a clockwise direction and southern hemisphere in a counter-clockwise direction • Currents affect the climates on the coast. NC’s coast is warmer in the winter because warm waters heat up the air and keep the climate warmer and in summer the cooler waters cool the air and keep the climate cooler. (it acts like a heater and AC)
What is the Gulf Stream? • Most of the information known about currents was gathered in the Gulf Stream by earlier sailors. • It is located in the North Atlantic Ocean. • It was discovered by Ponce de Leon in the 1500’s. • It flows from Florida northeastward toward North Carolina. • It is a warm current because it originates near the equator.
Current Discussion • Why are currents along the eastern coasts of continents usually warm while those along the western coasts are cold? • Currents along the eastern coasts originate at the equator, where the amount of energy absorbed from the Sun is the greatest; currents along western coasts originate at high latitudes where water receives less solar energy.
What are density currents? • Density current: Form when more dense seawater sinks beneath less dense coldwater. • Seawater becomes more dense when it gets colder. • Occur deep in the ocean where wind is not a factor. • Ex. Pg.205 in textbook. • They act like a conveyer belt: cold water from the ice caps on the bottom and warm water moving on the top.
Could density currents stop? How would this effect climate? • Yes, if Earth’s temperature rose enough, ice would not form on the polar regions. • In turn, their would not be any cold water supplying the density current “conveyer belt”. • This process could result in drastic climate shift.
What is upwelling? • Upwelling: A current in the ocean that brings, deep cold water to the surface. • Upwelling brings nutrients from the bottom of the ocean to the top.
Do Now 11/18/09 • Answer the following questions in complete sentences: • What is salinity? • How does oxygen get into sea water? • What are the three levels of water temperature in the ocean? Put then in order from most deep to least deep.
Today's Routine • Do Now • Chapter 7-1 Reinforcement Handout • Chp.7-2 Notes • Chapter 7-2 Reinforcement Handout • Rap-up Session • Announcements
Homework • Use your notes and textbook to complete the following task: • Create five questions that are not in the textbook or your notes with the information learned in chapter 7-1,7-2. Try to “stump” your classmates with your questions. You may use the internet and other resources to gain more knowledge on the topics learned.