کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5779495 1634684 2017 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Deglacial and Holocene sea-ice variability north of Iceland and response to ocean circulation changes
ترجمه فارسی عنوان
تغییرات آب و هوایی دریای شمال و هولزن در شمال ایسلند و پاسخ به تغییرات گردش خون در اقیانوس
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات علوم زمین و سیاره ای (عمومی)
چکیده انگلیسی
Sea-ice conditions on the North Icelandic shelf constitute a key component for the study of the climatic gradients between the Arctic and the North Atlantic Oceans at the Polar Front between the cold East Icelandic Current delivering Polar surface water and the relatively warm Irminger Current derived from the North Atlantic Current. The variability of sea ice contributes to heat reduction (albedo) and gas exchange between the ocean and the atmosphere, and further affects the deep-water formation. However, lack of long-term and high-resolution sea-ice records in the region hinders the understanding of palaeoceanographic change mechanisms during the last glacial-interglacial cycle. Here, we present a sea-ice record back to 15 ka (cal. ka BP) based on the sea-ice biomarker IP25, phytoplankton biomarker brassicasterol and terrestrial biomarker long-chain n-alkanols in piston core MD99-2272 from the North Icelandic shelf. During the Bølling/Allerød (14.7-12.9 ka), the North Icelandic shelf was characterized by extensive spring sea-ice cover linked to reduced flow of warm Atlantic Water and dominant Polar water influence, as well as strong meltwater input in the area. This pattern showed an anti-phase relationship with the ice-free/less ice conditions in marginal areas of the eastern Nordic Seas, where the Atlantic Water inflow was strong, and contributed to an enhanced deep-water formation. Prolonged sea-ice cover with occasional occurrence of seasonal sea ice prevailed during the Younger Dryas (12.9-11.7 ka) interrupted by a brief interval of enhanced Irminger Current and deposition of the Vedde Ash, as opposed to abruptly increased sea-ice conditions in the eastern Nordic Seas. The seasonal sea ice decreased gradually from the Younger Dryas to the onset of the Holocene corresponding to increasing insolation. Ice-free conditions and sea surface warming were observed for the Early Holocene, followed by expansion of sea ice during the Mid-Holocene.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Earth and Planetary Science Letters - Volume 472, 15 August 2017, Pages 14-24
نویسندگان
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