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In the Arctic, multi-year sea ice is being rapidly replaced by seasonal sea ice. Baffin Bay, situated between Greenland and Canada, is part of the seasonal ice zone. In this study, we present a long-term multi-mission assessment (2003–2020) of spring sea ice thickness in Baffin Bay from satellite altimetry and sea ice charts. Sea ice thickness within Baffin Bay is calculated from Envisat, ICESat, CryoSat-2, and ICESat-2 freeboard estimates, alongside a proxy from the ice chart stage of development that closely matches the altimetry data. We study the sensitivity of sea ice thickness results estimated from an array of different snow depth and snow density products and methods for redistributing low-resolution snow data onto along-track altimetry freeboards. The snow depth products that are applied include a reference estimated from the Warren climatology, a passive microwave snow depth product, and the dynamic snow scheme SnowModel-LG. We find that applying snow depth redistribution to represent small-scale snow variability has a considerable impact on ice thickness calculations from laser freeboards but was unnecessary for radar freeboards. Decisions on which snow loading product to use and whether to apply snow redistribution can lead to different conclusions on trends and physical mechanisms. For instance, we find an uncertainty envelope around the March mean sea ice thickness of 13 % for different snow depth/density products and redistribution methods. Consequently, trends in March sea ice thickness from 2003–2020 range from −23 to 17 cm per decade, depending on which snow depth/density product and redistribution method is applied. Over a longer timescale, since 1996, the proxy ice chart thickness product has demonstrated statistically significant thinning within Baffin Bay of 7 cm per decade. Our study provides further evidence for long-term asymmetrical trends in Baffin Bay sea ice thickness (with −17.6 cm per decade thinning in the west and 10.8 cm per decade thickening in the east of the bay) since 2003. This asymmetrical thinning is consistent for all combinations of snow product and processing method, but it is unclear what may have driven these changes.
Bibliographical noteFunding Information:
Acknowledgements. This work was funded primarily by an internal University of Bristol PGR Scholarship of IAG. Jack C. Landy acknowledges support from the Natural Environment Research Council Project PRE-MELT under grant NE/T000546/1 and the Diatom-ARCTIC project (NE/R012849/1) part of the Changing Arctic Ocean programme, jointly funded by the UKRI NERC and the German Federal Ministry of Education and Research (BMBF). Jack C. Landy received support from the European Space Agency tender EXPRO+ Snow under grant ESA AO/1-10061/19/I-EF. Jack C. Landy acknowledges support from the Centre for Integrated Remote Sensing and Forecasting for Arctic Operations (CIRFA) project through the Research Council of Norway (RCN) under grant no. 237906. Alek A. Petty and Nathan T. Kurtz were supported by NASA’s ICESat-2 Project Science Office. Julienne C. Stroeve acknowledges her Canada 150 Research Chair fund- ing and funding from NASA under grant NASA 15-CRYO2015-0019/NNX16AK85G15.
Financial support. This research has been supported by the Uni-
Ice Data Center (NSIDC). Envisat and CryoSat-2 freeboard data are available from the ESA Climate Change Initiative (https://doi.org/10.5285/54e2ee0803764b4e84c906da3f16d81b, Hendricks et al., 2018b; https://doi.org/10.5285/5b6033bfb7f241e, Hendricks et al., 2018a). Ice charts are available from the Canadian Ice Service (https://iceweb1.cis.ec.gc.ca/Archive/page1.xhtml? lang=en, Canadian Ice Service, Environment and Climate Change Canada, 2021). ULS draught observations in Davis Strait from the Applied Physics Laboratory, University of Washington, are available at http://psc.apl.uw.edu/sea_ice_cdr/Sources/Davis_Strait.html (Moritz et al., 2019). The merging of CryoSat-2 and SMOS data was funded by the ESA project SMOS & CryoSat-2 Sea Ice Data Product Processing and Dissemination Service, and data from March 2011 to March 2020 were obtained from https://spaces.awi.de/pages/viewpage.action?pageId=291898639 (Ricker et al., 2021b) (grant no. REKLIM-2013-04). The sea ice thickness dataset generated in this study is available on https://doi.org/10.5523/bris.2peywz756l8182cpwlanm4ratz (Glissenaar, 2021).
© Authors 2021
- sea ice
- satellite altimetry
- Baffin Bay