Interhemispheric Phasing of Millennial-Duration Climate Events During the Last 100 ka
Michael L Bender (Princeton University, Department of Geosciences, Princeton, NJ 08544; ph. 609-258-2936; fax 609-258-5242; Internet: firstname.lastname@example.org)
A number of studies have correlated isotopic temperature records of Antarctic ice cores into the Greenland temperature records using variations in methane concentration and the d18O of O2. Three Antarctic cores have been correlated in this way - Vostok (East Antarctica), Byrd (West Antarctica), and Taylor Dome (Transantarctic Mountains, East Antarctica). The results show that:
1. Long interstadial events and most short interstadial events during marine isotope stages 2, 3 and 4 in Greenland have corresponding events in Antarctica.
2. During Stage 3, millennial scale events were out of phase between Greenland and West Antarctica. Vostok and Taylor Dome are not sufficiently precisely dated to establish phasing during Stage 3.
3. Millennial duration climate change during Termination 1 was out of phase between Byrd and the Greenland ice cores. Vostok is not precisely dated for this interval but appears to be in phase with Byrd. Taylor Dome, on the other hand, is in phase with Greenland, or nearly so, Unlike Byrd, which begins warming at 18 ka, Taylor Dome begins warming about 15 ka, around the onset of the Bolling/Allerod in Greenland. Also unlike Byrd and Vostok, Taylor Dome cools slightly during the Younger Dryas.
One can regard climate change during Termination 1 as having a northern response (H1 from 18 - 16.5 ka, abrupt warming at ~ 14.6 ka, and Younger Dryas cooling from ~ 12.8 - 11.7 ka), and a southern response (warming beginning at about 18 ka and a cold reversal preceding the Younger Dryas). Studies of the Taylor Dome ice core show that the "northern response", previously recognized in the tropics and New Zealand, extends to Antarctica. The "southern response" is documented by meltwater events in the Arctic Seas and by melting of northern hemisphere ice sheets recorded in sea level rise beginning by 18 ka or earlier. While we can certainly say that changes in ocean circulation contributed to the complex pattern of climate change during Termination 1, the detailed nature of the climate teleconnections remains to be established.