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2,000-year-long temperature and hydrology reconstructions from the Indo-Pacific warm pool
Nature
Vol. 460, No. 7259, pp. 1113-1116, 27 August 2009.
doi:10.1038/nature08233
Delia W. Oppo1, Yair Rosenthal2, & Braddock K. Linsley3
1 Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA.
2 Institute of Marine and Coastal Sciences, and Department of Earth and Planetary Sciences, Rutgers, The State University, New Brunswick, New Jersey 08901, USA.
3 Department of Atmospheric and Environmental Sciences, University at Albany-State University of New York, Albany, New York 12222, USA.
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ABSTRACT:
Northern Hemisphere surface temperature reconstructions suggest that
the late twentieth century was warmer than any other time during the
past 500 years and possibly any time during the past 1,300 years.
These temperature reconstructions are based largely on terrestrial
records from extra-tropical or high-elevation sites; however, global
average surface temperature changes closely follow those of the global
tropics, which are 75% ocean. In particular, the tropical Indo-Pacific
warm pool (IPWP) represents a major heat reservoir that both influences
global atmospheric circulation and responds to remote northern high-
latitude forcings. Here we present a decadally resolved continuous sea
surface temperature (SST) reconstruction from the IPWP that spans the
past two millennia and overlaps the instrumental record, enabling both
a direct comparison of proxy data to the instrumental record and an
evaluation of past changes in the context of twentieth century trends.
Our record from the Makassar Strait, Indonesia, exhibits trends that
are similar to a recent Northern Hemisphere temperature reconstruction.
Reconstructed SST was, however, within error of modern values from
about AD 1000 to AD 1250, towards the end of the Medieval Warm Period.
SSTs during the Little Ice Age (approximately AD 1550-1850) were
variable, and ~0.5° to 1°C colder than modern values during the
coldest intervals. A companion reconstruction of δ18O of sea water -
a sea surface salinity and hydrology indicator - indicates a tight
coupling with the East Asian monsoon system and remote control of
IPWP hydrology on centennial-millennial timescales, rather than
a dominant influence from local SST variation.
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