miércoles, 10 de junio de 2009
Confirm:El Niño is back
Ocean temperatures in the equatorial Pacific are showing signs that an old acquaintance is about to pay a new visit. He will rearrange the meteorological furniture across the planet and probably outstay his welcome. According to the Climate Prediction Center, it looks like El Niño is coming back.
El_nino Sea surface temperatures have warmed across the Pacific's midsection during the Spring, and more importantly, a large pulse of subsurface warmth has propagated from west to east. Click on the image of this surface warmth -- the key El Niño region is to the right of the International Dateline at 180 degrees longitude -- and watch the heat below the surface move across the ocean this spring from the western Pacific off southern Asia to the eastern Pacific off South America.
"These surface and subsurface oceanic anomalies typically precede the development of El Niño," the climate center observed in its monthly discussion of conditions in the region.
Upperocean While most, but not all, models forecast the development of an El Niño this summer, forecasting these events is still a work in progress. The more compelling evidence comes from the observed data, such as this time diagram showing upper ocean temperatures in the central and eastern Pacific becoming anomalously warm this Spring.
El Niño conditions have a variety of impacts around the globe, although every event is different. Typically, upper-level westerly winds intensify, a circumstance that could suppress the development of some Atlantic hurricanes this summer. During winter, the North Pacific jetstream flattens its trajectory and moves farther south, which usually brings more warm winter storms across Southern California and Southeastern US. The Pacific Northwest often experiences warmer and drier winters.