ENSO-correlated fluctuations in ocean bottom pressure and wind-stress curl in the North Pacific

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Abstract
We examine the magnitude of ENSO-correlated variations in wind-stress curl and ocean bottom pressure in the North Pacific between 1992 until 2010, using satellite observations and model output. Our analysis indicates that while there are significant fluctuations correlated with some El Ni\~no and La Ni\~na events, the correlation is still relatively low. Moreover, the ENSO-correlated variability explains only 50 \% of the non-seasonal, low-frequency variance. There are significant residual fluctuations in both wind-stress curl and ocean bottom pressure in the region with periods of 4-years and longer. One such fluctuation began in late 2002 and has been observed by the Gravity Recovery and Climate Experiment (GRACE). Even after accounting for ENSO variations, there is a significant trend in ocean bottom pressure in the region, equivalent to 0.7 \textpm 0.3 cm yr-1 of sea level from January 2003 until December 2008, which is confirmed with steric-corrected altimetry. Although this low-frequency fluctuation does not appear in an ocean model, we show that the winds used to force the model have a significantly reduced trend that is inconsistent with satellite observations over the same time period.
Year of Publication
2011
Journal
Ocean Science Discussions
Volume
8
Number of Pages
1631-1655
Date Published
07/2011
DOI
10.5194/osd-8-1631-2011