Pan-Arctic wintertime lead frequency and distribution from thermal infrared satellite imagery, 2003-2015

Abstract:

Polynyas and leads are key elements of the wintertime Arctic sea-ice cover. They play a crucial role in surface heat loss, potential ice formation and consequently in the seasonal sea-ice budget. We apply and evaluate lead segmentation techniques based on sea-ice surface temperatures as measured by the Moderate Resolution Imaging Spectroradiometer (MODIS). A fuzzy cloud artifact filter is implemented to mitigate cloud artifacts and the associated potential misclassification of leads. We present quasi-daily pan-Arctic lead maps and monthly lead frequencies for the months of January to April from 2003 to 2015 at a spatial resolution of less than 2 km². An investigation of the inter-annual regional lead dynamics reveals pronounced patterns with significant variability mainly in the marginal ice zone and in the Beaufort Sea and with an obvious impact of bathymetry in proximity to shelf breaks (Fig. 1). The quasi-daily lead product can be used to deduct the occurrence, structure and dynamics of wintertime sea-ice leads and to assess seasonal divergence patterns of the Arctic Ocean.