The Atlantic multidecadal variability and its impact on Svalbard climate: insights from Linnevatnet varve record
Abstract
Svalbard is at the forefront of sea-ice changes in the Arctic making it an ideal place to study past hydrological variability associated with changes in sea surface temperatures and sea-ice cover. Here, we provide physical and geochemical data from an annually laminated record from Linnevatnet. Comparison between instrumental temperature from the Airport spanning the last 120 years and the physical parameter (grain-size and varve thickness) reveal a strong link (r = 0.52, p < 0.001). This is also the case with instrumental rainfall, although there are many gaps in these datasets. This suggests that the Linnevatnet varve record is sensitive to both temperature and rainfall. A strong positive correlation is also found between the long-term instrumental temperature data and the Atlantic Multidecadal Variability (AMV) suggesting that AMV plays a great role on Svalbard climate. Grain-size and varve thickness variability over the past ~900 years highlight periodicities at 76 and 65 year that are closely related to those observed in the instrumental AMV. Wavelet analysis of this annual record captures a significant and persistent power band located around 60-70 years for the past 900 years. Comparison of the new reconstructed AMV (Wang et al., 2017) and the physical parameters at Linnevatnet supports that the AMV has been modulating Svalbard climate for the past 9 decades. Among the noticeable features in the sedimentary record, a remarkable decrease in values is observed in early 18thcentury. However, the 20thcentury and more specifically the two recent decades have seen radical changes in the Linnevatnet record, including in year 2016 when coarse-grain-size and varve thickness (and Calcium) reached unprecedented values that coincide with both highest summer temperatures and largest rainstorm event recorded in observational record. Finally, this varve record will be potentially extended to the past 6000 years with new cores recovered this Spring, which could substantially help us to better understand the AMV evolution in the past.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMPP34A..05L
- Keywords:
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- 0424 Biosignatures and proxies;
- BIOGEOSCIENCES;
- 0473 Paleoclimatology and paleoceanography;
- BIOGEOSCIENCES