SLO 2

Circulation Systems

What is the Coriolis Effect?

Our planet is not flat. I say this because there are people who still think that (I know). Because of this, the equator must travel further than the poles in the same amount of time. If you decided to fly from the equator to the north pole, you would not appear to be heading straight north. It would appear that you were curving to the right (east). It would be the opposite if you were heading for the south pole. You would still be traveling east, but now you would be going to the left. This happens because the center bulging part of the planet is constantly playing catch up.

NORTHERN HEMISPHERE TO THE RIGHT/SOUTHERN HEMISPHERE TO THE LEFT

The Three

Atmospheric Cells

There are three major convection cells. The air rises at the equator, moves away until thirty degrees latitude, then moves down and around, causing the Hadley Cell. The air that cycles from that thirty degree mark to the sixty degree mark is the Ferrel Cell, and the Polar cell is from that sixty degree mark to the poles. Remember that this is mirrored in the Northern and Southern Hemispheres.

With these cells comes wind. The Westerlies, which we hear about often in the United States, are the dominant winds in the Ferrel Cell area. The others, such as the trade winds and the polar easterlies, are found in the Hadley and Polar cells respectively.

The Zones Converge

It is important to go over the Intertropical Convergence Zone (ITCZ). This area is where the trade winds "converge". This is a low pressure area. Low pressure areas occur when air rises, and high pressure areas occur when air descends. Sailors who get stuck in a windless zone at the equator because the air is rising above them call this the doldrums.

While there is low pressure at the equator, at about thirty degrees latitude there is a high pressure zone called the Horse Latitudes. At sixty degrees you will find the Polar Front, a low pressure system.

Works Cited

"What Are The Doldrums?", National Ocean Service, https://oceanservice.noaa.gov/facts/doldrums.html#:~:text=The%20%22doldrums%22%20is%20a%20popular%20nautical%20term%20that,to%20sailors%20around%20the%20world%20as%20the%20doldrums.

Textbook Webb Chapter 8 Oceans and Climate

Ocean Circulation

As mentioned before, there really is only one ocean. All this water is circulating around the globe is some pretty cool ways. The first is surface currents (westerlies and trade winds), which make up about 10% of the oceans circulation system. Gyres are circular patterns of this surface circulation that are created by high latitude currents bringing colder water to low latitude currents. There are five major gyres; North Atlantic, South Atlantic, North Pacific, South Pacific, and the Indian gyres.

The other 90% of the oceans circulation is Thermohaline* Circulation. You know the saying "hot air rises"? Well, so does warmer water. Warmer water is less dense and sits above colder, more dense water. As water gets colder, it will eventually freeze, but will leave its salt behind. Causing the water in that area to increase in its salinity. Then, as the ice melts, the water is added back into the mix. This movement with warmer and cooler water mixing around is the made source of circulation in our ocean system.

*Thermo = Temp Haline= Salt

Works Cited

Textbook Webb Chapter 9 Ocean Circulation

Fun Fact: This Circuit (see above photo) will take one to two thousand years to complete a single lap. Really slow race!

The Gulf Stream Waters

"From the Redwood Forrest to the Gulf Stream waters, this land was made for you and me." Know that the song is stuck in your head, what is the Gulf Stream? It sits along the western Pacific Ocean (Eastern United States) and is a very important part of ocean circulation. The currents come up from the equator along the coast very quickly and is concentrated in a narrow passage (Western Intensification). It comes hard and fast. As it reaches Canada, it is hit by colder water from the North Atlantic Current and veers off towards Europe. Once there it meets the Canary Current and heads down the coast until it reaches the North Equatorial Current and the whole thing starts over. This is the North Atlantic Gyre!

Works Cited

Textbook Webb Chapter 9 Ocean Circulation

Upwelling Vs Downwelling

These are important terms to know. Upwelling brings deeper, nutrient rich water up to the surface. Downwelling brings oxygen rich surface water to the deeper part of the ocean. This occurs both in the open ocean and along coastlines as well. This process is important to anything living in the oceans.

How Important Is All Of This?

Climate change is slowing down our ocean's circulation. Without it, there will be no more oxygen in the water, and therefore everything, and I do mean everything, in the ocean will die! After that, humans will be toast!

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