An 800kyr planktonic δ18O stack for the Western Pacific Warm Pool

Abstract

The Western Pacific Warm Pool (WPWP) exhibits different glacial-interglacial climate variability compared to high latitudes, and its sea surface temperatures are thought to respond primarily to changes in greenhouse forcing. To better characterize the orbital-scale climate response covering the WPWP, we constructed a planktonic δ18O stack (average) of 10 previously published WPWP records of the last 800kyr, available at 10.5281/zenodo.10211900 (Bowman et al., 2023), using the new Bayesian alignment and stacking software BIGMACS (Lee et al., 2023b). Similarities in stack uncertainty between the WPWP planktonic δ18O stack and benthic δ18O stacks, also constructed using BIGMACS, demonstrate that the software performs similarly well when aligning regional planktonic or benthic δ18O data. A total of 65 radiocarbon dates from the upper portion of five of the WPWP cores suggest that WPWP planktonic δ18O change is nearly synchronous with global benthic δ18O during the last glacial termination. However, the WPWP planktonic δ18O stack exhibits a smaller glacial-interglacial amplitude and less spectral power at all orbital frequencies than benthic δ18O. We assert that the WPWP planktonic δ18O stack provides a useful representation of orbital-scale regional climate response and a valuable regional alignment target, particularly over the 0 to 450ka portion of the stack.