HR: 08:45h
AN: PP21C-04 INVITED     [Abstracts]
TI: Evidence for High Latitude Influence On Tropical Oceans Over the Pliocene and Pleistocene Epochs
AU: * Herbert, T
EM: Timothy_Herbert@brown.edu
AF: Brown University, Dept. of Geological Sciences 324 Brook St., Providence, RI 02912-1846 United States
AU: Lui, Z
EM: Zhonghui_Liu@brown.edu
AF: Brown University, Dept. of Geological Sciences 324 Brook St., Providence, RI 02912-1846 United States
AU: Lawrence, K
EM: Kira_Lawrence@brown.edu
AF: Brown University, Dept. of Geological Sciences 324 Brook St., Providence, RI 02912-1846 United States
AU: Cleaveland, L
EM: Laura_Cleaveland@brown.edu
AF: Brown University, Dept. of Geological Sciences 324 Brook St., Providence, RI 02912-1846 United States
AB: Whether tropical or high latitude climate feedbacks dominate the signal of global climate change is an important, but difficult problem to solve. In the orbital frequency band, the presence of 41 kyr (obliquity) variations in low latitude records provides one unequivocal line of evidence that, in at least some important aspects, the high latitudes drive much of the climatic variance of the last 5 Ma. The effects of obliquity on either seasonal or mean annual insolation are very small in the tropics; furthermore, the effects on mean annual insolation in the tropics are in the opposite sense to those at latitudes $>$ 45 $^{o}$. Here we compare spectral signatures from a variety of surface water proxy records from tropical locations of Pliocene and Pleistocene age. The proxies can be related to high latitude glaciation by comparing their response to benthic isotopic data gathered from the same cores. We find many periods of time in which obliquity variations, in phase with high latitude glaciation, dominated marine tropical surface records. The data imply a tight coupling between feedbacks to insolation originating in the high latitudes and their transmission to low latitude parts of the globe.
DE: 4231 Equatorial oceanography
DE: 4267 Paleoceanography
DE: 1620 Climate dynamics (3309)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting