Effects of recent La Nina events on global mean sea level and ocean mass
Abstract
Interannual fluctuations of the global mean sea level are highly correlated with ENSO events, with positive (negative) anomalies during El Nino (La Nina). In a previous study we showed that during the 1997-1998 El Nino, the positive anomaly observed in the global mean sea level was mostly caused by an increase of the ocean mass component related to increased precipitation over the tropical Pacific ocean. In the present study we study the effects of recent La Nina events (since 2005) on the global mean sea level as well as on its thermal and mass components. As found by previous authors, we confirm that the large sea level drop associated with the 2011 La Nina results from the combined decrease of the steric and ocean mass components, the latter dominating the sea level signal. But we also show that the corresponding ocean mass drop arises essentially in the northeastern Pacific (just as we previously found for the 1997-1998 El Nino, but with opposite sign). During the 2011 La Nina, the spatial pattern of the ocean mass drop is quite similar to those observed for sea level and steric component. Extending the analysis back in time, we find that the ocean mass component present similar spatial patterns during both El Nino and La Nina but with opposite sign. Such patterns are likely related to the net precipitation patterns affecting the eastern part of the tropical Pacific during ENSO events.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.G34A..04C
- Keywords:
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- 1641 GLOBAL CHANGE Sea level change;
- 4556 OCEANOGRAPHY: PHYSICAL Sea level: variations and mean;
- 4513 OCEANOGRAPHY: PHYSICAL Decadal ocean variability;
- 1225 GEODESY AND GRAVITY Global change from geodesy