HR: 1340h
AN: PP23A-1394    [Abstracts]
TI: Southern Hemisphere mid-Latitude Sea Surface Temperature Changes 0-150,000 years BP: Low- {\it Versus} High-Latitude Orbital Forcing
AU: * Pahnke, K
EM: kpahnke@mit.edu
AF: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 United States
AU: Sachs, J P
EM: jsachs@mit.edu
AF: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 United States
AU: Manighetti, B
EM: b.manighetti@niwa.co.nz
AF: National Institute of Water and Atmospheric Research (NIWA), PO Box 14901, Wellington, 6003 New Zealand
AB: The climatic and oceanographic history of the Southern Hemisphere, particularly the mid-latitudes, is still largely unknown and the understanding of mid- to high-latitude climate coupling consequentially incomplete. We have generated three new alkenone sea surface temperature (SST) records from mid-southern latitudes that reveal differential subtropical and subantarctic climatic changes over the past 150,000 years. Subantarctic SST variability mirrors changes in global ice volume that are linked to Northern Hemisphere summer insolation. Subtropical SST, on the other hand, show a strong eccentricity modulation of the precession cycle and warmer conditions during glacial stage 6 than during the last glacial maximum. Consistent subtropical warming between 20-45 ky coincides with an eccentricity minimum and a decrease in orbital precession (Northern Hemisphere insolation maximum). These patterns highlight the impact of orbital eccentricity on climate through the modulation of the precession cycle at low latitudes. The apparent differential response of subtropical and subantarctic summer SST to changes in earth's orbital parameters has implications for the meridional temperature gradient and hence changes in atmospheric circulation and moisture transport to high latitudes.
DE: 4267 Paleoceanography
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting