Landfast ice properties over the Beaufort Sea region in 2000-2019 from MODIS and Canadian Ice Service data

Two decades (2000-2019) of the landfast ice properties in the Beaufort Sea region in the Canadian Arctic were analyzed at 250 m spatial resolution from two sources: (1) monthly maps derived at the Canada Centre for Remote Sensing from the Moderate Resolution Imaging Spectroradiometer clear-sky satellite image composites; and (2) Canadian Ice Service charts. Detailed comparisons have been conducted for the landfast ice spatial extent, the water depth at, and the distance to the outer seaward edge from the coast in four sub-regions: (1) Alaska coast; (2) Barter Island to Herschel Island; (3) Mackenzie Bay; and (4) Richards Island to Cape Bathurst. The results from both sources demonstrate good agreement. The average spatial extent for the entire region over the April-June period is 48.5 (+ or -5.0) X 10 (super 3) km (super 2) from Canadian Ice Service data versus 45.1 (+ or -6.1) X 10 (super 3) km (super 2) from satellite data used in this study (7.0% difference). The correlation coefficient for April-June is 0.73 (p = 2.91 X 10 (super -4) ). The long-term linear trends of the April-June spatial extent since 2000 demonstrated statistically significant decline: -4.45 (+ or -1.69) X 10 (super 3) km (super 2) /decade and -4.73 (+ or -2.17) X 10 (super 3) km (super 2) /decade from Canadian Ice Service and satellite data, respectively. The landfast ice in the Beaufort Sea region showed the general tendency for an earlier break-up, later onset, and longer ice-free period. The break-up date has decreased by 7.6 days/decade in the Mackenzie Bay region. The western part of the study area did not demonstrate statistically significant changes since 2000.