Estimate the latitude where warm El Niño water is located. Equator. To the West of Peru in the Pacific

4. Describe the thermocline during normal, El Niño, and La Niña phases. Normal = very shallow near coast of Peru (in the East). Slopes down to further depths in the West. El Nino = basically the same across the equator. Thermocline moves much deeper into ocean. 5. Describe changes in ocean temperatures characterizing each phase. Normal = colder water near surface near Peru (East). Much warmer near surface as you go West. El Nino = Warmer water throughout the equator

7. How does the North Pacific jet stream change from the mean during the January-March 1998 phase of the El Niño? It’s more separated and disjointed. It doesn’t move as one single stream or “river” of air.

10. How does the weather in the northwestern part of the United States differ between El Niño and La Niña? How does it differ in the southern United States? Warmer and drier winters for us because the Jet Stream has been moved further north or is weakened.

HW: How does the lack of cold water upwelling during an El Nino event affect life in the ocean (ISB 34) Normally, winds blow warm surface waters away from Peru across the equator. During an El Nino event, these winds weaken, leaving warmer water at the surface. This warm water is less dense and prevents colder, deeper, more dense waters from coming to the surface due to upwelling. (it’s like putting a lid on the water so it can’t come to the top) Nutrients necessary for life are found in cold waters. If these cold water nutrients can’t mix with the sunlight at the surface, the primary producers can’t thrive. They are the basis of the food chain and other consumers, therefore, run out of food and cannot survive in the region. They may move temporarily to other areas or die off during this El Nino phase. *** This occurs every 2-7 years *** http://www.csa.com/discoveryguides/archives/elnino.php