Reconstructing High Arctic growing season intensity from shoot length growth of a dwarf shrub

Annual shoot length of the circumarctic dwarf shrub Cassiope tetragona has proved to be a reliable proxy for past and ongoing climate change in the Arctic. This is based on its strong linear relationship with monthly climate parameters. Monthly means are, however, coarse units for prediction of grow...

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Bibliographic Details
Published in:The Holocene
Main Authors: Weijers, S., Wagner-Cremer, F., Sass, U.G.W., Broekman, R., Rozema, J.
Format: Article in Journal/Newspaper
Language:English
Published: 2013
Subjects:
baffin-island
cassiope-tetragona
climate signals
core delta-o-18 records
ice variability
retrospective analysis
salix-arctica
summer temperature
surface air-temperature
svalbard
Arctic
Svalbard
Baffin Island
Baffin
Cassiope tetragona
Climate change
Online Access:https://research.wur.nl/en/publications/reconstructing-high-arctic-growing-season-intensity-from-shoot-le
https://doi.org/10.1177/0959683612470178
Description
Summary:Annual shoot length of the circumarctic dwarf shrub Cassiope tetragona has proved to be a reliable proxy for past and ongoing climate change in the Arctic. This is based on its strong linear relationship with monthly climate parameters. Monthly means are, however, coarse units for prediction of growth in marginal regions with short growing seasons. An alternative to monthly averages are parameters that quantify the growing season length (GSL) and its intensity (growing degree-days; GDD5). GDD5 is defined as the cumulative daily mean temperature above 5°C. GSL is defined as the number of days on which the average temperature exceeds 5°C. The aims of this study were to test whether these parameters are a better predictor of growth than monthly means and to reconstruct past High Arctic growing season climate. Correlative analysis shows that GDD5 is a better predictor of annual shoot length growth than mean monthly temperatures and GSL, both at C. tetragona’s European northern and southern distribution limit, as well as at its assumed climatic optimum. Svalbard Airport GDD5 was reconstructed back to 1857. The reconstruction shares 61% of variance with the instrumental record. This opens the possibility to obtain an Arctic network of climate reconstructions with high temporal and spatial resolution through construction of C. tetragona shoot length chronologies.

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