High frequency climate variability of the Norwegian Atlantic Current during the early Holocene period and a possible connection to the Gleissberg cycle

Abstract

A high-resolution sediment core (MD95-2011) from the Vøring Plateau has been studied to document the variability of the surface water conditions during the Younger Dryas—Preboreal (13—9 kyr BP) in the eastern Norwegian Sea, in order to assess the climate variability in a period considered to be highly dynamic. Quantitative summer sea surface temperatures (SSSTs) with a time resolution of 20—40 years are reconstructed using three different diatom transfer function methods. The Younger Dryas—Preboreal transition at site MD95-2011 is documented with a temperature increase of 3.5°C/3°C within 100 years. Following, the record resolves for the first time PBO as two prominent cooling events centred at 11.2 and 11.3 kyr BP. In addition, a broad cooling event documented from 10.3—9.9 kyr BP coincides with previously documented climatic events as the 10.3 event and Erdalen Event 1 (10.1—9.9 kyr BP) and 2 (~9.7 kyr BP), respectively. Constrained by the observed SSST changes and diatom assemblages, short-term SSST changes with a periodicity of 80—120 years are observed, and the length of this period might indicate a possible connection to the solar Gleissberg cycle. The North Atlantic heat transport is highly sensitive to freshwater inputs, and the interplay of freshwater forcing with insolation forcing is considered as the controlling mechanism of climate changes at site MD05-2011 during the early Holocene. However, the century-scale variability of 80—120 years cannot explain the large-scale variability during the early Holocene, but is of importance for understanding the underlying small-scale oscillations.