Summer Sea-Surface Temperatures and Climatic Events in Vaigat Strait, West Greenland, during the Last 5000 Years

Dongling Li,Longbin Sha,Yanni Wu,Hui Jiang,Jialin Li,Yanguang Liu

doi:10.3390/su9050704

Abstract

We present a new reconstruction of summer sea-surface temperature (SST) variations over the past 5000 years based on a diatom record from gravity core DA06-139G, from Vaigat Strait in Disko Bugt, West Greenland. Summer SST varied from 1.4 to 5 °C, and the record exhibits an overall decreasing temperature trend. Relatively high summer SST occurred prior to 3000 cal. a BP, representing the end of the Holocene Thermal Maximum. After the beginning of the “Neoglaciation” at approximately 3000 cal. a BP, Vaigat Strait experienced several hydrographical changes that were closely related to the general climatic and oceanographic evolution of the North Atlantic region. Distinct increases in summer SST in Vaigat Strait occurred from 2000 to 1600 cal. a BP and from 1200 to 630 cal. a BP, and are consistent with the “Roman Warm Period” and the “Mediaeval Warm Period” in the North Atlantic region. The summer SST decreased significantly during 1500~1200 cal. a BP and 630~50 cal. a BP, corresponding, respectively, to the Northeast Atlantic cooling episodes known as the “European Dark Ages” and “Little Ice Age”. Spectral and cross-correlation analyses indicate that centennial-scale oscillations in summer SST are superimposed on the long-term trend. The dominant periodicities are centered at 529, 410, and 191 years, which are close to the ubiquitous 512 and 206-year 14C cycle, suggesting that solar forcing may play an important role in summer SST variability in Disko Bugt.

Highlights

The Disko Bugt area in central West Greenland has attracted considerable research attention in recent years, and there have been studies of both oceanic variability [1,2,3,4] and fluctuations in tidewater-based ice streams such as Jakobshavns Isbrae [5,6,7,8,9]
The hydrography of the coastal waters of West Greenland is linked to the large-scale North Atlantic circulation system via the combined effects of the East Greenland Current (EGC) and the Irminger Current (IC), which merge to form the West Greenland Current (WGC; Figure 1)
Summer sea-surface temperatures (SSTs) off West Greenland are largely determined by the relative flow of Polar and Atlantic water masses within the WGC

Summary

Introduction

The Disko Bugt area in central West Greenland has attracted considerable research attention in recent years, and there have been studies of both oceanic variability [1,2,3,4] and fluctuations in tidewater-based ice streams such as Jakobshavns Isbrae [5,6,7,8,9]. Special attention has been paid to the variation of the ice sheet and the deglaciation during the late Quaternary, and to the nearshore-to-offshore ocean circulation during the Holocene. The hydrography of the coastal waters of West Greenland is linked to the large-scale North Atlantic circulation system via the combined effects of the East Greenland Current (EGC) and the Irminger Current (IC), which merge to form the West Greenland Current (WGC; Figure 1). Summer sea-surface temperatures (SSTs) off West Greenland are largely determined by the relative flow of Polar and Atlantic water masses within the WGC. Multi-proxy reconstructions of SST along West Greenland have so far mainly been qualitative [2,4,10,11]. Quantitative SST reconstructions on a long timescale are necessary to help understand the dynamics of the ocean-climate system

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Conclusion