Statistical predictability of the Arctic sea ice volume anomaly: identifying predictors and optimal sampling locations

• Published in: The Cryosphere
• Main Authors: L. Ponsoni, F. Massonnet, D. Docquier, G. Van Achter, T. Fichefet
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2020
• Subjects: Environmental sciences; GE1-350; Geology; QE1-996.5; Arctic; Laptev Sea; Chukchi Sea; North Pole; Beaufort Sea; Canadian Archipelago; Chukchi; laptev; Sea ice; The Cryosphere
• Online Access: https://doi.org/10.5194/tc-14-2409-2020; https://doaj.org/article/48ea35016ce84bb39d5ca2171c098859

This work evaluates the statistical predictability of the Arctic sea ice volume (SIV) anomaly – here defined as the detrended and deseasonalized SIV – on the interannual timescale. To do so, we made use of six datasets, from three different atmosphere–ocean general circulation models, with two different horizontal grid resolutions each. Based on these datasets, we have developed a statistical empirical model which in turn was used to test the performance of different predictor variables, as well as to identify optimal locations from where the SIV anomaly could be better reconstructed and/or predicted. We tested the hypothesis that an ideal sampling strategy characterized by only a few optimal sampling locations can provide in situ data for statistically reproducing and/or predicting the SIV interannual variability. The results showed that, apart from the SIV itself, the sea ice thickness is the best predictor variable, although total sea ice area, sea ice concentration, sea surface temperature, and sea ice drift can also contribute to improving the prediction skill. The prediction skill can be enhanced further by combining several predictors into the statistical model. Applying the statistical model with predictor data from four well-placed locations is sufficient for reconstructing about 70 % of the SIV anomaly variance. As suggested by the results, the four first best locations are placed at the transition Chukchi Sea–central Arctic–Beaufort Sea (79.5 ∘ N, 158.0 ∘ W), near the North Pole (88.5 ∘ N, 40.0 ∘ E), at the transition central Arctic–Laptev Sea (81.5 ∘ N, 107.0 ∘ E), and offshore the Canadian Archipelago (82.5 ∘ N, 109.0 ∘ W), in this respective order. Adding further to six well-placed locations, which explain about 80 % of the SIV anomaly variance, the statistical predictability does not substantially improve taking into account that 10 locations explain about 84 % of that variance. An improved model horizontal resolution allows a better trained statistical model so that the reconstructed values ...