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- Sundqvist, Hanna S., et al.
(författare)
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Arctic Holocene proxy climate database - new approaches to assessing geochronological accuracy and encoding climate variables
- 2014
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Ingår i: Climate of the Past. - : Copernicus GmbH. - 1814-9324 .- 1814-9332. ; 10:4, s. 1605-1631
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Tidskriftsartikel (refereegranskat)abstract
- We present a systematic compilation of previously published Holocene proxy climate records from the Arctic. We identified 170 sites from north of 58 degrees N latitude where proxy time series extend back at least to 6 cal ka (all ages in this article are in calendar years before present - BP), are resolved at submillennial scale (at least one value every 400 +/- 200 years) and have age models constrained by at least one age every 3000 years. In addition to conventional meta-data for each proxy record (location, proxy type, reference), we include two novel parameters that add functionality to the database. First, climate interpretation is a series of fields that logically describe the specific climate variable(s) represented by the proxy record. It encodes the proxy-climate relation reported by authors of the original studies into a structured format to facilitate comparison with climate model outputs. Second, geochronology accuracy score (chron score) is a numerical rating that reflects the overall accuracy of C-14-based age models from lake and marine sediments. Chron scores were calculated using the original author-reported C-14 ages, which are included in this database. The database contains 320 records (some sites include multiple records) from six regions covering the circumpolar Arctic: Fennoscandia is the most densely sampled region (31% of the records), whereas only five records from the Russian Arctic met the criteria for inclusion. The database contains proxy records from lake sediment (60 %), marine sediment (32 %), glacier ice (5 %), and other sources. Most (61 %) reflect temperature (mainly summer warmth) and are primarily based on pollen, chironomid, or diatom assemblages. Many (15 %) reflect some aspect of hydroclimate as inferred from changes in stable isotopes, pollen and diatom assemblages, humification index in peat, and changes in equilibrium-line altitude of glaciers. This comprehensive database can be used in future studies to investigate the spatio-temporal pattern of Arctic Holocene climate changes and their causes. The Arctic Holocene data set is available from NOAA Paleoclimatology.
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| 2. |
- Gjerde, M., et al.
(författare)
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Holocene multi-proxy environmental reconstruction from lake Hakluytvatnet, Amsterdamoya Island, Svalbard (79.5 degrees N)
- 2018
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Ingår i: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791. ; 183, s. 164-176
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Tidskriftsartikel (refereegranskat)abstract
- High resolution proxy records of past climate are sparse in the Arctic due to low organic production that restricts the use of radiocarbon dating and challenging logistics that make data collection difficult. Here, we present a new lake record from lake Hakluytvatnet at Amsterdamoya island (79.5 degrees N), the north-westernmost island on Svalbard. Multi-proxy analyses of lake sediments in combination with geomorphological mapping reveal large environmental shifts that have taken place at Amsterdamoya during the Holocene. A robust chronology has been established for the lake sediment core through 28 AMS radiocarbon ages, and this gives an exceptionally well-constrained age control for a lake at this latitude. The Holocene was a period with large changes in the Hakluytvatnet catchment, and the onset of the Neoglacial (ca. 5 ka) marks the start of modern-day conditions in the catchment. The Neoglacial is characterized by fluctuations in the minerogenic input to the lake as well as internal productivity, and we suggest that these fluctuations are driven by atmospherically forced precipitation changes as well as sea ice extent modulating the amount of moisture that can reach Hakluytvatnet. (C) 2017 Elsevier Ltd. All rights reserved.
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