NASA | GSFC | JPL | Site Map |
|
||
Education: Student Outcomes |
Filtered by outcome, asset type: 5-8q5, video Click here to begin a new search | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Outcome: Explain the effect of solar energy heat on ocean circulation. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Grade level: 5-8 Theme: ocean circulation Video: salinity_importance.flv The salt in the ocean affects its density, just like the temperature affects its density. And the density, meaning the amount of mass per volume, is going to then impact how the ocean circulates, it's going to impact where the water goes as it circulates throughout the globe. Grade level: 5-8 Theme: ocean circulation Video: salt_of_earth_03.flv
Jeff Halverson: "Climate change on earth is complicated by the fact that the ocean moves much more slowly than the atmosphere. So you have warming in the atmosphere, warming in the ocean, but they're occurring at different speeds. So they're out of sync, and that makes predicting what's going to happen in the next hundred or two years very, very difficult." Susan Lozier: "Now what we might expect happens, in a very simplistic sense, is that as the ocean warms, there's going to be more evaporation. And that more evaporation would would mean that oceans become saltier. But really it's not just that simple because there's also evaporation, precipitation, and the ice as well, and that's all wrapped up in the study of the hydrologic cycle." (source) Grade level: 5-8 Theme: ocean circulation Video: salt_of_earth_02.flv
Jeff Halverson: "It takes perhaps a thousand years for the water to cycle through the deep ocean. So we say the oceans have a memory. They're like a tape recorder. Things that happen now will still be manifest hundreds of years in the future as that cold water moves through this giant circulation." Susan Lozier: "So if there's any change to that overturning circulation, that means that Northern Europe and the British Isles would be robbed of that heat due to those waters that are returning to the high latitudes." (source) Grade level: 5-8 Theme: ocean circulation Video: sst_reverse_direction.flv
Grade level: 5-8 Theme: ocean circulation Video: thermohaline_conveyor_iPod.m4v.flv
This animation shows one of the major regions where this pumping occurs: the North Atlantic Ocean around Greenland, Iceland, and the North Sea. The surface ocean current brings new water to this region from the South Atlantic via the Gulf Stream and the water returns to the South Atlantic via the North Atlantic Deep Water current. The continual influx of warm water into the North Atlantic polar ocean keeps the regions around Iceland and southern Greenland mostly free of sea ice year round. The animation also shows another feature of the global ocean circulation: the Antarctic Circumpolar Current. The region around latitude 60 degrees south is the the only part of the Earth where the ocean can flow all the way around the world with no land in the way. As a result, both the surface and deep waters flow from west to east around Antarctica. This circumpolar motion links the world's oceans and allows the deep water circulation from the Atlantic to rise in the Indian and Pacific Oceans and the surface circulation to close with the northward flow in the Atlantic. (source) Grade level: 5-8 Theme: ocean circulation Video: thermohaline_rev.flv
The animation also shows another feature of the global ocean circulation: the Antarctic Circumpolar Current. The region around latitude 60 south is the only part of the Earth where the ocean can flow all the way around the world with no obstruction by land. As a result, both the surface and deep waters flow from west to east around Antarctica. This circumpolar motion links the world's oceans and allows the deep water circulation from the Atlantic to rise in the Indian and Pacific Oceans, thereby closing the surface circulation with the northward flow in the Atlantic. The color on the world's ocean's at the beginning of this animation represents surface water density, with dark regions being most dense and light regions being least dense (see the animation Sea Surface Temperature, Salinity and Density). The depths of the oceans are highly exaggerated (100x in oceans, 20x on land) to better illustrate the differences between the surface flows and deep water flows. The actual flows in this model are based on current theories of the thermohaline circulation rather than actual data. The thermohaline circulation is a very slow moving current that can be difficult to distinguish from general ocean circulation. Therefore, it is difficult to measure or simulate. This version of the visualization combines the Earth look of the original thermohaline visualization with the new thermohaline flow field generated for the Science on a Sphere production, "Loop". (source) |