Atmospheric forcing of sea ice anomalies in the Ross Sea pol
Details of Research
TitleAtmospheric forcing of sea ice anomalies in the Ross Sea polynya regionAbstractWe investigate the impacts of strong wind events on the sea ice concentration within the Ross Sea polynya (RSP), which may have consequences on sea ice formation. Bootstrap sea ice concentration (SIC) measurements derived from satellite SSM/I brightness temperatures are correlated with surface winds and temperatures from Ross Ice Shelf automatic weather stations (AWSs) and weather models (ERA-Interim). Daily data in the austral winter period were used to classify characteristic weather regimes based on the percentiles of wind speed. For each regime a composite of a SIC anomaly was formed for the entire Ross Sea region and we found that persistent weak winds near the edge of the Ross Ice Shelf are generally associated with positive SIC anomalies in the Ross Sea polynya and vice versa. By analyzing sea ice motion vectors derived from the SSM/I brightness temperatures we find significant sea ice motion anomalies throughout the Ross Sea during strong wind events, which persist for several days after a strong wind event has ended. Strong, negative correlations are found between SIC and AWS wind speed within the RSP indicating that strong winds cause significant advection of sea ice in the region. We were able to partially recreate these correlations using colocated, modeled ERA-Interim wind speeds. However, large AWS and model differences are observed in the vicinity of Ross Island, where ERA-Interim underestimates wind speeds by a factor of 1.7 resulting in a significant misrepresentation of RSP processes in this area based on model data. Thus, the cross-correlation functions produced by compositing based on ERA-Interim wind speeds differed significantly from those produced with AWS wind speeds. In general the rapid decrease in SIC during a strong wind event is followed by a more gradual recovery in SIC. The SIC recovery continues over a time period greater than the average persistence of strong wind events and sea ice motion anomalies. This suggests that sea ice recovery occurs through thermodynamic rather than dynamic processes. Copyright Author(s) 2017.AcknowledgementsWe would like to thank the support of the University of Wisconsin-Madison Automatic Weather Station Program for the AWS observational data set (NSF grant numbers ANT-0944018, ANT-1245663, ANT-0943952 and ANT-1245737). We would also like to acknowledge the NSIDC for the provision of the SSM/I data set. This work was partially funded by a grant from the New Zealand Antarctic Research Institute, scholarships from both the Department of Physics and Astronomy at the University of Canterbury and NZ Post (administered by Antarctica New Zealand).Funding DetailsANT-0943952, NSF, National Science Foundation; ANT-0944018, NSF, National Science Foundation; ANT-1245663, NSF, National Science Foundation; ANT-1245737, NSF, National Science Foundation; UC, University of Canterbury; UW, University of Wisconsin-Madison
Details
1st AuthorDale, E.AuthorDale, E.McDonald, A.Coggins, J.Rack, W.Year2017JournalCryosphereVolume11Number1Pages267-280DOI10.5194/tc-11-267-2017URLhttps://www.scopus.com/inward/recor.....9209b2a4e4a0932b69ef7a18aKeywordsrank5ProgrammeK055 - Dynamics in the Antarctic Middle Atmosphere - MF calibration
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TypeArticleCitationDale, E., McDonald, A., Coggins, J. and Rack, W. (2017). Atmospheric forcing of sea ice anomalies in the Ross Sea polynya region. Cryosphere, 11(1): 267-280 IdentifierDale2017Relevancerank5Antarctica NZ supported?YesNZARI?Yes
Linked To
Rack, W., Atmospheric forcing of sea ice anomalies in the Ross Sea pol , [Dale2017]. Antarctica NZ, accessed 25/08/2026, https://adam.antarcticanz.govt.nz/nodes/view/63462, 10.5194/tc-11-267-2017