El Nino, La Nina and Sea Ice
September 20, 2001
El Nino, La Nina and Sea Ice may sound like the names of Columbus's three ships on his here-to-fore unknown voyage to try to reach India via a polar route, instead they have to do with oceanic and atmospheric interactions.
Scientists have been mystified by observations that when sea ice on one side of Antarctica recedes, it advances farther out on the other side. Now recent findings by David Rind at the Goddard Institute of Space Studies suggest that this is the result of El Niños and La Niñas driving changes in the subtropical jet stream, which then alters the track of storm systems that push sea ice around the continent of Antarctica.
The map above shows the difference in sea ice cover between 1992 and 1999 around Antarctica. The red color indicates areas where there was a higher concentration of sea ice in 1992 than in 1999, as a result of a 1992 El Nino event. The blue color indicates places where ice cocenntrations were higher in 1999 than 1992, as a result of a 1999 La Nina event.