The AutoICE Challenge

Mapping sea ice in the Arctic is essential for maritime navigation, and growing vessel traffic highlights the necessity of the timeliness and accuracy of sea ice charts. In addition, with the increased availability of satellite imagery, automation is becoming more important. The AutoICE Challenge investigates the possibility of creating deep learning models capable of mapping multiple sea ice parameters automatically from spaceborne synthetic aperture radar (SAR) imagery and assesses the current state of the automatic-sea-ice-mapping scientific field. This was achieved by providing the tools and encouraging participants to adopt the paradigm of retrieving multiple sea ice parameters rather than the current focus on single sea ice parameters, such as concentration. The paper documents the efforts and analyses, compares, and discusses the performance of the top-five participants’ submissions. Participants were tasked with the development of machine learning algorithms mapping the total sea ice concentration, stage of development, and floe size using a state-of-the-art sea ice dataset with dual-polarised Sentinel-1 SAR images and 22 other relevant variables while using professionally labelled sea ice charts from multiple national ice services as reference data. The challenge had 129 teams representing a total of 179 participants, with 34 teams delivering 494 submissions, resulting in a participation rate of 26.4 %, and it was won by a team from the University of Waterloo. Participants were successful in training models capable of retrieving multiple sea ice parameters with convolutional neural networks and vision transformer models. The top participants scored best on the total sea ice concentration and stage of development, while the floe size was more difficult. Furthermore, participants offered intriguing approaches and ideas that could help propel future research within automatic sea ice mapping, such as applying high downsampling of SAR data to improve model efficiency and produce better results

Observations from C-Band SAR Fully Polarimetric Parameters of Mobile Sea Ice Based on Radar Scattering Mechanisms to Support Operational Sea Ice Monitoring

Fully polarimetric (FP) SAR systems offer parameters that describe and quantify the scattering mechanisms from the surface cover. These are usually derived from decomposition of matrices derived from the original scattering matrix from observations at each pixel. Power from scattering mechanisms have potential for retrieval of sea ice information, which cannot be derived using traditional backscatter (magnitude or phase) measured by single- or dual-polarization SAR systems. This study investigates the potential of selected FP parameters that represent the power of three scattering mechanisms, in addition to the total power, in identifying ice types and surface features for operational use. Parameters were obtained from a set of 62 RADARSAT-2 Quad-pol data over Resolute Passage, central Arctic, during the period September-December 2017. A scattering-based color-composite scheme was developed. Analysis of the examined color images was supported by information from regional ice charts and SAR image interpretations from the Canadian Ice Service. Case studies are presented to demonstrate the potential of the proposed color-composite tool. Open water, new ice, multi-year ice and a few surface features including rafted, ridged and smooth/rough surfaces can be identified better in the color images. Physical interpretation of the relative power from the given scattering mechanisms is explained for the relevant ice types and surfaces

Oil detection in RADARSAT-2 quad-polarization imagery: Implications for ScanSAR performance

Environment Canada's Integrated Satellite Tracking of Pollution (ISTOP) program uses RADARSAT-2 data to vector pollution surveillance assets to areas where oil discharges/spills are suspected in support of enforceme

On the Intermittent Formation of an Ice Bridge (Nunniq) across Roes Welcome Sound, Northwestern Hudson Bay and Its Use to Local Inuit Hunters

Ice bridges are unique features that form when sea ice consolidates and remains immobilized within channels. They form in many locations throughout the Arctic and are typically noted for the polynyas that form on their lee side. However, ice bridges also provide a temporary platform that may be used by both humans and wildlife to cross otherwise impassable channels. For generations, Inuit in Coral Harbour, Nunavut, have used an ice bridge to cross Roes Welcome Sound and expand their hunting territory, though they report that the bridge only forms approximately every four years. Of interest both to Inuit and the scientific community is why the bridge forms so intermittently, by what mechanisms, and whether the frequency will change with ongoing warming and sea ice loss. Using satellite imagery, we determined that the bridge formed during 14 of the past 50 years (1971 – 2020). Generally, the bridge forms between January and March during a cold period that coincides with neap tide and after surface winds have rotated from the prevailing northerly (along-channel) winds to west-northwesterly (across-channel) winds. This rotation compresses the existing ice pack against Southampton Island, where it remains stationary because of the calm along-channel winds and low tidal range and coalesces under cold air temperatures. Breakup occurs between mid-June and early July after the onset of melt. Overall, the bridge forms when a specific set of conditions occur simultaneously; however, a warming climate, specifically a reduction in very cold days and a shorter ice season may affect the frequency of bridge formation, thereby limiting Inuit travel.Les ponts de glace sont des caractéristiques uniques qui se forment lorsque la glace de mer se consolide et reste immobilisée dans les chenaux. Ils se forment en maint endroit de l’Arctique et se démarquent généralement par les polynies qui se créent de leur côté sous le vent. Cependant, les ponts de glace font aussi office de plateforme temporaire dont peuvent se servir tant les humains que la faune pour traverser des chenaux qui seraient autrement impraticables. Depuis des générations, les Inuits de Coral Harbour, au Nunavut, empruntent un pont de glace pour traverser le détroit de Roes Welcome et agrandir leur territoire de chasse, même si selon eux, ce pont ne se forme qu’aux quatre ans environ. Les Inuits et les scientifiques se demandent pourquoi le pont se forme de manière si intermittente, grâce à quels mécanismes ils apparaissent, et si la fréquence de formation des ponts va changer en raison du réchauffement continu et de la perte de glace de mer. À l’aide d’imagerie satellitaire, nous avons déterminé qu’un pont s’est formé durant 14 des 50 dernières années (1971–2020). De manière générale, le pont apparaît entre janvier et mars pendant une période froide qui coïncide avec la marée de morte-eau, après la rotation des vents de surface, qui passent des vents dominants du nord (longeant le chenal) aux vents de l’ouest-nord-ouest (traversant le chenal). Cette rotation a pour effet de comprimer la banquise actuelle contre l’île Southampton, où elle demeure stationnaire en raison des vents calmes longeant le chenal et de la faible amplitude de la marée, et où elle coalesce sous les froides températures de l’air. La dislocation se produit entre la mi-juin et le début de juillet, après le début de la fonte des glaces. Dans l’ensemble, le pont se forme lorsque certaines conditions se manifestent simultanément. Toutefois, le réchauffement climatique, plus précisément en ce qui a trait à la réduction du nombre de journées très froides et au raccourcissement de la saison des glaces, pourrait avoir un effet sur la fréquence de la formation du pont, ce qui limiterait les déplacements des Inuits