Processes controlling environmental change in the subarctic Pacific Ocean on millennial to orbital timescales are not well understood. Here we use a 230-kyr sedimentary record from the northwest Pacific Ocean to assess the response of late Pleistocene sediment dynamics to orbital forcing. Combining a source-to-sink perspective based on sedimentological records with climate model reanalysis, we reveal that fluctuations in sediment provenance were closely linked to obliquity-forced changes in atmospheric circulation modes. Specifically, the position of the Aleutian Low controlled sediment transport from the Bering Sea and Aleutian Arc sources. Furthermore, a distinct shift in North Pacific ocean circulation during the Last Glacial Maximum may have been related to a strengthened Siberian High. The coincidence of atmospheric mode switches with changes in sea-ice extent and North Pacific Intermediate Water formation in the marginal seas suggests that this coupled ocean-atmosphere system may have acted as a regional amplifier of global climate variability.
Subject classification (UKÄ)
- Climate Research