This year's El Niño phenomenon is extraordinarily strong
22.12.2015: Not every Christmas Child receives a warm welcome: the fishermen of Peru have to fight with the climate phenomenon El Niño, where warm surface water of the Pacific displaces the cold and nutrient rich upwelling water off the Peruvian coast and with this the fish.
The sea level change caused by El Niño can be observed by satellites with radar altimetry. Researcher Tilo Schöne of the GFZ German Research Centre for Geosciences has produced an animation of the temporal changes of the sea level in the Pacific from data of the Jason-2 satellite in which this climate phenomenon is clearly seen. Every ten days the radar measurements are composed to a new picture. Thus, Tilo Schöne’s animation is a time lapse view of the Pacific sea level from January to December 2015.
At the beginning of the year, the Pacific presents itself more or less according to the long term mean. Since the middle of the year, however, a sea level rise starts to build up which is mainly caused by temperature: the ocean water expands due to the rising temperature of the central and eastern Pacific. In the animation this is depicted in red colour. At the end of the film, in December 2015, the current situation is displayed as a 40 centimeter increase of the sea level compared to the long term average. The maximum of the El Niño is expected in January/February 2016.
El Niño is probably the most known natural climate phenomenon. In a „normal“ state of atmospheric circulation, the north-eastern and south eastern trade winds compile a hill of warm water in the central Pacific Ocean. Thus, the cold upwelling water of the Humboldt current can come up to the sea surface off South America. For the fish searching food this is ideal as it is for the fishermen. If, for reasons which are not yet completely clear, the trade wind circulation breaks down, this warm water hill swashes eastward up to the American west coasts. This happens unregularly every three to seven years and reaches its maximum around Christmas. Therefore, the Peruvian fishermen called this climate variation “El Niño“, the Christmas Child.
El Niño has far reaching implications. Strong rainfalls, floods and high water temperatures in the Eastern Pacific regions correlate to extreme droughts and bush fires in Indonesia and Australia. Even in Antarctica a connection with El Niño is found: In El Niño-years enhanced precipitation in West-Antarctica and below-average snowfall on the Antarctic Peninsula is found. And California may hope for the rain it needs so urgently.
The animation can be found here:
Sea level deviations in the Pacific from January to December 2015 in meters (Graphic.: T. Schöne, GFZ German Research Centre for Geosciences)