Ja, maar alleen lokaal, niet globaal. La Nina geeft normaal meer ijs in Ross-Amundsen en minder ijs in Weddell zee.
Wouter
Aanvulling: stukje tekst uit mijn doctoraat.
3.3.2 ENSO and the Southern Ocean
Next to the tropical changes, ENSO has influences almost everywhere in the world. It has an influence too in the region that is important for us, the Southern Ocean. The mechanisms linking the tropical part of ENSO to the flects seen in the Southern Ocean are discussed in Liu et al. (2002b) and Yuan (2004).
There is a distinct influence of the ENSO phenomenon on the Bellingshausen Sea and the Antarctic Peninsula. Thanks to the many stations on the last one, the ENSO-due variability is well represented in this region.
As the SOI is high, which is equivalent with a low MEI-index8, i.e. in a La Niña situation, there is a large low pressure anomaly west of the Antarctic Peninsula, especially in winter (Kwok and Comiso, 2002a; Turner, 2004; Yuan, 2004). On the contrary, in SOI-low cases, low pressure areas are relatively absent in this region. The net result is a warmer Antarctic Peninsula in SOI-high cases, although the correlation between the SOI and the temperature at Faraday (west coast of the Antarctic Peninsula) is not significant. This is due to the large amount of noise in the temperatures at the Antarctic Peninsula created by various sources of natural variability (like SAM). However, in the Eastern Bellingshausen Sea, the signal/noise ratio of the SOI-influence of the temperature is larger, showing a significant warming at high SO-indexes (Kwok and Comiso, 2002a). Although this effect is quite robust, one of the most important low-SOI-periods (1982-1983) did not show those effects (Turner, 2004). The SSTs change accordingly as could be expected from the pressure anomalies with higher eastern Bellingshausen Sea and lower Ross Sea SSTs in high SOI-years. The Antarctic continent close to the Ross Sea also cools (Bertler et al., 2004). Finally, the sea ice in Ross Sea increases in high SOI-years, while the sea ice off the coast of the Antarctic Peninsula decreases (Figure 3.8) (Yuan and Martinson, 2000). It is important to note that the surface pressure pattern in high SOI-years is
very similar to the one in high SAM-years, despite no correlation between the respective indices. As a result, part of the warming of the Antarctic Peninsula is maybe due to the small downward trend in the SOI-index (Kwok and Comiso, 2002a; Stammerjohn et al., 2003).
Finally, Genthon and Cosme (2003) have shown that an important part of the precipitation variability is probably ENSO-driven.
8The MEI-index is the Multivariate ENSO Index and is positive in a El-Niño phase and thus anticorrelates with the SOI-index. It can be found at http://www.cdc.noaa.gov/people/klaus.wolter/MEI/mei.html.
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