Geography and Oceanography - Chapter 15 potx

[...]... nutrients Kills fish and sea birds - especially bad off Peru Animations Ocean AND Atmosphere El Niño is both an oceanic and an atmospheric phenomenon – Often called ENSO Scientists knew of SO from wind and precip data Scientists knew of El Niño from SST data Didn’t make connection until 1969 Jacob Bjerknes Jacob Bjerknes, a Norwegian meteorologist made breakthrough in 1969 Combined wind, rain, AND SST data... “teleconnections” We must understand in order to predict Invest in soybean futures after an El Niño! – No fish meal for cattle, farmers will use soy We’re dealing with the interplay between two very different fluids - atmosphere and ocean - in the boundless dimensions of time and space Abnormality in one causes abnormality in the other Events such as El Niños have no definite starting point and no end It’s a matter... Suppressed Sea Surface “Southern Oscillation” (SO) Tradewinds weaken or fail Tropical winds reverse and go east instead of west Atmospheric pressure cells reverse – Wet areas become dry (drought) – Dry areas get flooded “oscillates” like a giant sea-saw, taking 3-5 months Non El Niño El Niño Coupled Ocean-Atmosphere Circulation Non El Niño El Niño Ocean’s Response to the SO Warm water moves to the east... Wet areas get wetter (floods) Occurs in between El Niños INDEX = • Air temperature • Sea surface temp • Surface winds • Cloudiness of sky • Sea level pressure El Niño AND La Niña Both an ocean/atmosphere phenomenon Both affect wind, rain, and SST Both occur in cycles More Animations El Niño VERSUS La Niña “Southern Oscillation” Tradewinds fail Reverse flow of air Elevated SST Upwelling decreased Fish... Bjerknes was a meterologist who was willing to take a good, hard look at oceanographic data Oceanography a versatile science How Do We Track El Niño Today? in situ (on site) measurements Satellite sea surface temperature Computer models Autonomous Temperature Line Acquisition System Tropical Ocn Global Atm Tropical Atm-Ocn La Niña NOT tied to the Southern Oscillation Tradewinds get stronger SSTs are lowered... abnormality in the other Events such as El Niños have no definite starting point and no end It’s a matter of where you break into the scene, and where you leave it Perhaps the only thing more complex is human behavior itself Dr Jerome Namias, Scripps Institution of Oceanography . recent and severe events in Most recent and severe events in 1953, ‘5 7- 58, ‘65, ‘7 2- 73, ‘7 6- 77, 1953, ‘5 7- 58, ‘65, ‘7 2- 73, ‘7 6- 77, ‘8 2- 83 ‘8 2- 83 , ‘9 1- 92, , ‘9 1- 92, ‘9 7- 98 ‘9 7- 98 ,. ‘0 2- 04, , ‘0 2- 04, ‘0 6- 07, ’09’10 ‘0 6- 07, ’09’10 Slides from 198 2- 83 El Niño Slides from 198 2- 83 El Niño