Decadal-Scale SST and Salinity Variations in the Central Tropical Pacific: Signatures of Natural and Anthropogenic Climate Change
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Nurhati-2011-July-Decadal-Scale SST.pdf
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Author(s)
Nurhati, Intan Suci
Cobb, Kim M.
Lorenzo, Emanuele Di
Date Issued
June 2011
Journal
Journal of Climate
Publisher
American Meteorological Society
Citation
Nurhati, Intan S., Kim M. Cobb, and Emanuele Di Lorenzo. “Decadal-Scale SST and Salinity Variations in the Central Tropical Pacific: Signatures of Natural and Anthropogenic Climate Change.” Journal of Climate 24.13 (2011): 3294-3308. Web. 2 Feb. 2012. © 2011 American Meteorological Society
Version
Final published version
Abstract
Accurate projections of future temperature and precipitation patterns in many regions of the world depend on quantifying anthropogenic signatures in tropical Pacific climate against its rich background of natural variability. However, the detection of anthropogenic signatures in the region is hampered by the lack of continuous, century-long instrumental climate records. This study presents coral-based sea surface temperature (SST) and salinity proxy records from Palmyra Island in the central tropical Pacific over the twentieth century, based on coral strontium/calcium and the oxygen isotopic composition of seawater (δ[superscript 18]OSW), respectively. On interannual time scales, the Sr/Ca-based SST record captures both eastern and central Pacific warming "flavors" of El Niño–Southern Oscillation (ENSO) variability (R = 0.65 and 0.67, respectively). On decadal time scales, the SST proxy record is highly correlated to the North Pacific gyre oscillation (NPGO) (R = −0.85), reflecting strong dynamical links between the central Pacific warming mode and extratropical decadal climate variability. Decadal-scale salinity variations implied by the coral-based δ[superscript 18]OSW record are significantly correlated with the Pacific decadal oscillation (PDO) (R = 0.54). The salinity proxy record is dominated by an unprecedented trend toward lighter δ[superscript 18]OSW values since the mid–twentieth century, implying that a significant freshening has taken place in the region, in line with climate model projections showing enhanced hydrological patterns under greenhouse forcing. Taken together, the new coral records suggest that low-frequency SST and salinity variations in the central tropical Pacific are controlled by different sets of dynamics and that recent hydrological trends in this region may be related to anthropogenic climate change.
MIT Department
Singapore-MIT Alliance in Research and Technology (SMART)
Singapore-MIT Alliance in Research and Technology (SMART)
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1175/2011jcli3852.1
