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Education: Student Outcomes |
Filtered by outcome: 9-12q3 Click here to begin a new search | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Outcome: Explain the influence of the El Niño Southern Oscillation on global weather patterns. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Grade level: 9-12 Theme: ocean circulation Video: elnino-320.flv
These data are from the Goddard Earth Modeling System, a coupled land-ocean-atmosphere model which uses earth and satellite-based observations to simulate the Earth's physical system during events such as El Niño. (source) Compare this video with Components of the Water Cycle: Flow of Atmospheric Water Vapor. Grade level: 9-12 Theme: ocean circulation Tool: http://mynasadata.larc.nasa.gov/preview_lesson.php?&passid=68
It is believed that El Niños occur every two to eight years, and are sometimes stronger, sometimes weaker. This often happens when the southeast trade winds weaken or even reverse. As a result, large masses of water from the western Pacific Ocean migrate to the east to the coast of South America. This change in ocean circulation not only impacts the weather and climate in South America, but also affects locations all around the globe. These effects can last for about a year, when the opposite conditions occur as the trade winds strengthen again, and the waters off the coast of South America are colder than normal from active upwelling occurring along the coast. This phase of the global circulation disruption is called La Niña. We have been fortunate over the last 30 years to have satellite and buoy data to warn us if the El Niño phase is upon us. By measuring sea surface heights with satellites like TOPEX Poseidon, sea surface temperature with satellites like AVHRR, and wind vectors from buoys and satellites, we can monitor the Pacific Ocean for changes that may signal the onset of El Niño or La Niña. The sensitive altimeter on the TOPEX Poseidon satellite can measure small changes that create hills and valleys on the sea surface which is mostly caused by thermal expansion (steric effect), and the warming of the ocean during an El Niño event can be sensed by the altimeter. This lesson explores El Niño by looking at sea surface temperature, sea surface height, and wind vectors in order to seek out any correlations there may be among these three variables. It employs group work where different teams work together to analyze a single variable, and then get together in different groups to compare all three variables. The lesson will guide students through data representing the strong El Niño from 1997 to 1998. By doing this, students will model the methods of researchers who bring their expertise to study integrated science questions. Depending on the classroom dynamics, available technology, and available time, this lesson may be modified. Grade level: 9-12 Theme: ocean circulation Article: http://www.nasa.gov/centers/goddard/news/topstory/2003/0114salt.html
This study, conducted for NASA by University of Maryland researchers Joaquim Ballabrera, Tony Busalacchi, and Ragu Murtugudde, is one of the first to look at ocean salinity in El Niño, Southern Oscillation (ENSO) predictions and their relationship to tropical sea surface temperatures, sea level, winds, and fresh water from rain. Grade level: 9-12 Theme: ocean circulation Activity: http://www.tos.org/hands-on/teaching_phys_concepts.pdf
Thermal expansion is the principle by which a liquid thermometer works. In the ocean, thermal expansion is thought to contribute significantly to sea level rise on decadal-to-century-long time scales. However, thermal effects appear to be influenced by decadal climate-related fluctuations, making it difficult to estimate the long-term contribution of thermal expansion to sea level rise. Current estimates suggest that thermal expansion is responsible for 25 percent to 50 perccent of observed sea level rise. In this activity, we look at thermal expansion using two rods, one made of aluminum and the other made of PVC. When placed in cold water, both rods initially float because their densities are lower than that of the cold water. Over time, the PVC rod gets colder and contracts, which results in a density change. When the density of the rod exceeds that of the water, the PVC sinks. The aluminum rod gets colder too, but aluminum expands and contracts much less than PVC when its temperature is changed by the same amount; therefore, the aluminum rod's density is less affected by the temperature change, and it remains floating. Students will also try this experiment with hot water. Videos
Flash Video | QuickTime MovieGrade level: 9-12 Theme: ocean circulation Activity: documents/vtop_oc_variations_el_nino.pdf An El Niño is thought to be triggered when steady westward blowing trade winds weaken and even reverse direction in the western Pacific Ocean, near New Guinea and Australia. This change in the winds allows the large mass of warm water that is normally located in the western Pacific to move eastward along the equator until it reaches the coast of South America. This displaced pool of unusually warm water affects evaporation and where rain clouds form, altering the typical atmospheric jet stream patterns around the world. Scientists are studying information from satellites and in-water buoys to better understand the causes and effects of an El Niño. In this activity, students will analyze satellite images of sea surface temperature, sea surface topography, and wind data from an El Niño period and compare and contrast these data with non-El Niño conditions. |