Transcript El Nino
El Nino BIG IDEA: Abiotic and biotic factors influence the environment • Large-scale changes in atmospheric and ocean current patterns in which, among other things, warms surface water in the Pacific moves further to the east than normal • NORMAL: A convection cell is driven by heat at the ocean surface • Water from the surface evaporates and the warm, moist water rises, pulling in cool, dry air,and creating a loop that transfers heat and moisture out of the hot zone. • El Niño: During an El Niño, the hot spot moves east,creating two convection cells and altering climate around the Pacific basin. • The red indicates sea-surface temperature 5 degrees C above • A warmer ocean translates into more humidity and clouds in the area, thus creating global changes in jet stream circulation. • Since it's heat that drives the weather -- differences in temperature and pressure literally move air and moisture around the sky -- if you change the source of heat, you change the entire weather system. Effects of El Nino • More hurricanes in the Pacific • Induced droughts in the Amazon and Indonesia leading to fires • Intense rains in areas that are characteristically dry • Major storms in the NE U.S. • Flooding in the SE U.S. • catches of tropical fish off the West Coast of the United States • Global economy losses of around 8 billion dollars La Nina • Large-scale changes in atmospheric and ocean current patterns in which, among other things, warms surface water in the Pacific moves further to the west than normal • This results in below-normal sea surface temperatures in the eastern equatorial Pacific • Effects tend to be the opposite of El Nino such as below normal precipitation in areas of the U.S. Why do El Nino and La Nina Occur? • El Niño and La Niña result from interaction between the surface of the ocean and the atmosphere in the tropical Pacific. • Changes in the ocean impact the atmosphere and climate patterns around the globe. • In turn, changes in the atmosphere impact the ocean temperatures and currents. • The system oscillates between warm (El Niño) to neutral (or cold La Niña) conditions with an on average every 3-4 years.