Quantifying sea ice trends in the Southern Ocean: is extent or area the better measure? (2019)
This report presents an assessment of the relationship between sea ice area and extent measurements in the Southern Ocean, in order to scrutinise the significance of the reported trend of increasing Antarctic sea ice over the past 40 years. Two key research questions are addressed: How are Antarctic sea ice extent and area values calculated and what information (and to what accuracy) are they actually telling us about sea ice mass balance? How do measurements of sea ice extent and area compare between that derived from low resolution and high-resolution data? The methods undertaken include a close examination of the NSIDC sea ice concentration, area and extent data trends from 1978-2016, and a case study analysis in the Weddell Sea that compares sea ice concentration, extent and area data derived from low resolution passive microwave radiometers (SSM/IS and AMS2) and higher resolution SAR. The findings reveal that the average trend conceals a large amount of spatial and seasonal variability and that there are several extreme months throughout the record where extent anomalies significantly exceed area anomalies. It is suggested that this could be a reflection of either physical processes (e.g. wind behaviour) that may vary between regions, or instrumental errors. However, the fact that measures of sea ice thickness are not incorporated into record of sea ice cover, points to the conclusion that the reported rising trend in Antarctic sea ice cover in the past few decades is highly incomplete and cannot be used to interpret sea ice mass balance changes.
RightsAll Rights Reserved
Showing items related by title, author, creator and subject.
Route, Gail (University of Canterbury, 2015)Ocean acidification is regarded as one of the most recent threats to the global environment resulting from unprecedented absorption of elevated anthropogenic carbon dioxide emissions. The emerging research on the effect ...
Southern Ocean cloud and aerosol data: a compilation of measurements from the 2018 Southern Ocean Ross Sea Marine Ecosystems and Environment voyage Kremser S; Harvey M; Kuma P; Hartery S; Saint-Macary A; McGregor J; Schuddeboom A; von Hobe M; Lennartz ST; Geddes A; Querel R; Peltola M; Sellegri K; Silber I; Law CS; Flynn CJ; Marriner A; Hill TCJ; DeMott PJ; Hume CC; Plank G; Graham G; Parsons S; McDonald, Adrian (Copernicus GmbH, 2021)Due to its remote location and extreme weather conditions, atmospheric in situ measurements are rare in the Southern Ocean. As a result, aerosol–cloud interactions in this region are poorly understood and remain a major ...
Quantifying the area of the small-scale owners’ forest estate in the East Coast, Hawke’s Bay and Southern North Island Manley B; Morgenroth J; Xu C (2020)The National Exotic Forest Description (NEFD) estimated that, as at 1 April 2016, the small-scale forest estate area in the East Coast, Hawke’s Bay and Southern North Island (SNI-West and SNI-East) wood supply regions ...