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Uncovering an anthropogenic sea-level rise signal in the Pacific Ocean


Internal climate variability across a range of scales is known to contribute to regional sea-level trends1,2,3,4,5,6,7, which can be much larger than the global mean sea-level trend in many parts of the globe. Over decadal timescales, this internal variability obscures the long-term sea-level change3,6,8, making it difficult to assess the effect of anthropogenic warming on sea level. Here, an attempt is made to uncover the sea-level rise pattern in the tropical Pacific Ocean associated with anthropogenic warming. More specifically, the sea-level variability associated with the Pacific Decadal Oscillation is estimated and removed from the regional sea-level trends computed from satellite altimetry measurements over the past two decades. The resulting pattern of regional sea-level rise uncovered in the tropical Pacific Ocean is explained in part by warming in the tropical Indian Ocean, which has been attributed to anthropogenic warming9. This study represents one of the first attempts at linking the sea-level trend pattern observed by satellite altimetry to anthropogenic forcing.

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Figure 1: Pacific Decadal Oscillation (PDO)-related sea-level trends.
Figure 2: Pacific Decadal Oscillation (PDO)-related wind-stress trends.
Figure 3: Sea-level trend data–model comparison.


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The authors thank B. Fox-Kemper and R. Milliff for their comments, discussion and review of the paper. B.D.H. and R.R.L. acknowledge support from NASA ROSES Physical Oceanography grant NNX11AE26G and NASA Ocean Surface Topography Science Team grant NNX13AH05G. R.S.N. acknowledges support from NASA Interdisciplinary Science Grant NNX11AP27G. W.H. is supported by NSF CAREER award OCE 0847605. K-Y.K. acknowledges support by the ‘Ocean Climate Change: Analysis, Projections, Adaptation (OCCAPA)’ funded by the Ministry of Oceans and Fisheries, Korea.

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B.D.H. and R.R.L. conceived of the analysis conducted here; B.D.H. performed the analysis and wrote the paper. M.W.S. assisted in performing the data analysis. W.H. conducted the model experiments and assisted in writing the paper. K-Y.K. provided analysis tools. K-Y.K., R.R.L. and R.S.N. assisted in the synthesis and presentation of the results.

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Correspondence to B. D. Hamlington.

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Hamlington, B., Strassburg, M., Leben, R. et al. Uncovering an anthropogenic sea-level rise signal in the Pacific Ocean. Nature Clim Change 4, 782–785 (2014).

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