A quasi-daily pan-Arctic lead product derived from MODIS thermal infrared imagery

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 different lead segmentation techniques based on sea-ice surface temperatures as measured by the Moderate Resolution Imaging Spectroradiometer (MODIS). Daily lead composite maps indicate the presence of cloud artifacts that arise from ambiguities in the segmentation process and short comings in the MOIS cloud mask. A fuzzy cloud artifact filter is implemented to mitigate these effects and the associated potential misclassification of leads. The filteris adjusted with reference data from thermal infrared image sequences, and applied to daily MODIS data from January to April 2008. The daily lead product can be used to deduct the occurrence, structure and dynamics of winter time sea-iceleads and to assessseasonal diver gence patterns of the Arctic Ocean