Arctic Holocene proxy climate database - new approaches to assessing geochronological accuracy and encoding climate variables

• Published in: Climate of the Past
• Main Authors: Sundqvist, H. S., Kaufman, D. S., Mckay, N. P., Balascio, N. L., Briner, J. P., Cwynar, L. C., Sejrup, H. P., Seppa, H., Subetto, D. A., Andrews, J. T., Axford, Y., Bakke, J., Birks, H. J. B., Brooks, S. J., De Vernal, A., Jennings, A. E., Ljungqvist, F. C., Ruehland, K. M., Saenger, C., Smol, J. P., Viau, A. E.
• Format: Text
• Language: English
• Published: Copernicus Gesellschaft Mbh 2014
• Subjects: anthro-bio; geo; Arctic; Fennoscandia
• Online Access: https://doi.org/10.5194/cp-10-1605-2014; https://archimer.ifremer.fr/doc/00291/40216/38682.pdf; https://archimer.ifremer.fr/doc/00291/40216/38683.zip

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 ...