A shift to predominant multi-year sea ice conditions in the Baffin Bay and North Atlantic Ocean during the Holocene-Glacial transition inferred from the EGRIP ice core

Delia Segato,Federico Dallo,Andrea Spolaor,Camilla Marie Jensen,Federico Scoto,Carlo Barbante,Tobias Erhardt,Alfonso Saiz-Lopez,Azzurra Spagnesi,Helle Astrid Kjær,Niccolò Maffezzoli,Daniele Zannoni,Francois Burgay,Dorthe Dahl-Jensen,Clara Turetta

doi:10.5194/egusphere-egu21-6278

Abstract

&lt;p&gt;Arctic sea ice has been melting at unprecedented rates in the past decades. Understanding past sea ice variability is of paramount importance to contextualize recent changes and constrain global climate models. Bromine enrichment (Br&lt;sub&gt;enr&lt;/sub&gt;), relative to sea-water ratio, has been introduced as a proxy of first-year sea ice conditions within the ocean region influencing the ice core location (Spolaor et al., 2013). Br&lt;sub&gt;enr&lt;/sub&gt; has been measured in ice cores from Greenland, that is the NEEM and RECAP cores. NEEM sea ice proxies are influenced by the region of the Canadian Arctic and Baffin Bay, while for the RECAP core it is mainly the North Atlantic Ocean. In this study we present the first high-resolution record of bromine enrichment from the EGRIP ice core in Greenland for the last 15.7 kyr BP, covering the Holocene-Glacial transition.&lt;/p&gt;&lt;p&gt;From preliminary back-trajectory analyses we suggest that EGRIP sea ice proxy sources are located in a wide region in the Baffin Bay and North Atlantic Ocean. We find EGRIP Br&lt;sub&gt;enr&lt;/sub&gt; values of ~1 during cold periods, that is the Younger Dryas (12.9 &amp;#8211; 11.7 kyr BP) and the last part of the Oldest Dryas (15.7 &amp;#8211; 14.7 kyr BP), which we associate with predominant multi-year sea ice conditions. During warmer periods, instead, we observe higher Br&lt;sub&gt;enr&lt;/sub&gt; values, ~3 for the B&amp;#248;lling-Aller&amp;#248;d period (14.7 &amp;#8211; 12.9 kyr BP) and progressively higher values from the early Holocene onwards, likely associated with an increased seasonal sea ice area. EGRIP Br&lt;sub&gt;enr&lt;/sub&gt; is consistent with NEEM and RECAP records and it has the potential to extend our knowledge on Arctic past sea ice variability.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;&amp;#160;&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Bibliography&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Spolaor, A., Vallelonga, P., Plane, J. M. C., Kehrwald, N., Gabrieli, J., Varin, C., Turetta, C., Cozzi, G., Kumar, R., Boutron, C., and Barbante, C.: Halogen species record Antarctic sea ice extent over glacial&amp;#8211;interglacial periods, Atmos. Chem. Phys., 13, 6623&amp;#8211;6635, https://doi.org/10.5194/acp-13-6623-2013, 2013.&lt;/p&gt;

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