Open AccessSynchronous, high‐frequency oscillations in tropical sea surface temperatures and North Atlantic Deep Water production during the Last Glacial Cycle
Author(s) -
Curry W. B.,
Oppo D. W.
Publication year - 1997
Publication title -
paleoceanography
Language(s) - English
Resource type - Journals
eISSN - 1944-9186
pISSN - 0883-8305
DOI - 10.1029/96pa02413
Subject(s) - north atlantic deep water , geology , equator , oceanography , sea surface temperature , climatology , glacial period , interglacial , surface water , tropical atlantic , deglaciation , water mass , atmospheric sciences , thermohaline circulation , environmental science , latitude , holocene , geomorphology , geodesy , environmental engineering
Stable isotopic measurements of G. sacculifer and C. wuellerstorfi in a core from the western equatorial Atlantic imply that there are parallel, suborbital oscillations in surface water hydrography and deep water circulation occurring during oxygen isotope stages 2 and 3. Low values of G. sacculifer δ 18 O accompany high values of C. wuellerstorfi δ 13 C, linking warmer sea surface temperatures (SSTs) in the tropics with increased production of lower North Atlantic Deep Water (NADW). The amplitude of the δ 18 O oscillations is 0.6‰ (or 2°–3°C), which is superimposed on a glacial/interglacial amplitude of about 2.1‰. Using the G. sacculifer δ 18 O data, we calculate that surface waters were colder during stage 2 than calculated by CLIMAP [1976, 1981]. The longer‐period (>2 kyr) oscillations in air temperature recorded in the Greenland and Antarctic ice cores appear to correlate with oscillations in sea surface temperature in the equatorial Atlantic. The magnitude of these oscillations in tropical SST is too large to have resulted from changes in meridional heat transport caused by the global conveyor alone. The apparent synchroneity of equatorial SST and polar air temperature changes, as well as the amplitude of the SST changes at the equator, are consistent with the climate effects expected from changes in the atmosphere's greenhouse gas content (H 2 O vapor , CO 2 , and CH 4 ).