Sea Ice Melt Onset Dynamics in the Northern Canadian Arctic Archipelago from RADARSAT, 1997-2014

• Main Author: Mahmud, Mallik Sezan
• Other Authors: Yackel, John, Beauchamp, Benoit, Howell, Stephen, Hall-Beyer, Mryka
• Format: Master Thesis
• Language: English
• Published: Graduate Studies 2016
• Subjects: Physical Geography; Physical Oceanography; Remote Sensing; Environmental Sciences; Sea Ice; Synthetic Aperture Radar; Melt onset; Canadian Arctic; RADARSAT; Arctic; Canadian Arctic Archipelago; Arctic Archipelago; Sea ice
• Online Access: http://hdl.handle.net/11023/2736; https://doi.org/10.11575/PRISM/27719

An algorithm was developed to detect melt onset over Arctic sea ice using high-resolution SAR images from RADARSAT. The algorithm is based on the temporal evolution of the SAR backscatter coefficient (σ⁰), using an ice type specific threshold approach that also corrects for backscatter incidence angle variation. Using 4457 RADARSAT images, the algorithm was applied over sea ice in the northern CAA, thus generating a new time series of melt onset from 1997-2014. The mean annual melt onset date was on YD 164±4 (mid–June). No significant trend was found over the 18-year period, however, variability increased in post-2007 years. An earlier (later) melt onset was associated with increased (decreased) solar energy absorption and subsequently associated in lighter (heavier) September sea ice coverage in the northern CAA. RADARSAT estimates of melt onset were found to be in good agreement but more robust compared to passive microwave and scatterometer estimates.