HR: 1300h
AN: OS52D-05    [PDF]
TI: Climate and Hydrographic Changes in the Western Equatorial Pacific During the Last Millenium
AU: * Newton, A J
EM: anewton@geol.sc.edu
AF: Department of Geological Sciences, University of South Carolina 700 Sumpter St, Columbia, SC 29208 United States
AU: Thunell, R
EM: thunell@geol.sc.edu
AF: Department of Geological Sciences, University of South Carolina 700 Sumpter St, Columbia, SC 29208 United States
AU: Stott, L
EM: stott@usc.edu
AF: Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089 United States
AB: The Indo-Pacific Warm Pool presently is the warmest region the global ocean and is the source of significant interannual global climate variability through the El Ni¤o Southern Oscillation (ENSO). We have reconstructed records of sea surface temperature and salinity over the past millennium using both the Mg-Ca ratios and $\delta$$^{18}$O values of planktonic foraminifera shells from several marine cores taken between 10$\deg$S and 10$\deg$N in the Indonesian region. The cores have Holocene sedimentation rates ranging from 35 to 50 cm/1000 years and therefore are ideal for evaluating decadal scale climate variability. The modern average SST in the study area is approximately 28$\deg$C. From $\sim$600 to 1800 A.D., SST in this region of the Pacific ranged from 28 to 30$\deg$C. A pronounced cooling trend began at $\sim$1400 and lasted until $\sim$1700 A.D., a period of time equivalent to the Northern Hemisphere Little Ice Age (LIA). In particular, the lowest temperatures occur between $\sim$1640 and 1700 A.D., coinciding with the period of reduced solar intensity known as the Maunder Minimum. Prior to the LIA, between $\sim$700 and 1400 A.D. (the Medieval Warm Period, MWP), temperatures were 1-2$\deg$C warmer, ranging from 29-30$\deg$C. In addition to these large millennial scale variations, significant decadal to centennial scale variability is present throughout the record. These trends in the temperature record are similar to other late Holocene changes in hydrography reported for other regions of the tropics. For example, reconstructions of the migration of the Atlantic ITCZ (Huag, et al., 2001) suggest that during the LIA, periods of increased aridity in the Caribbean coincide with decreased temperatures in the Indo-Pacific Warm Pool. Similarly, warmer temperatures during the MWP in the western equatorial Pacific are associated with increased precipitation in the Caribbean, suggesting a link between hydrographic conditions in the tropical Pacific and Atlantic Oceans.
DE: 4215 Climate and interannual variability (3309)
DE: 4231 Equatorial oceanography
DE: 4267 Paleoceanography
DE: 4870 Stable isotopes
SC: Ocean Sciences [OS]
MN: 2004 Ocean Sciences Meeting