Global Sea Ice Coverage from Satellite Data: Annual Cycle and 35-Yr Trends

Well-established satellite-derived Arctic and Antarctic sea ice extents are combined to create the global picture of sea ice extents and their changes over the 35-yr period 1979-2013. Results yield a global annual sea ice cycle more in line with the high-amplitude Antarctic annual cycle than the lower-amplitude Arctic annual cycle but trends more in line with the high-magnitude negative Arctic trends than the lower-magnitude positive Antarctic trends. Globally, monthly sea ice extent reaches a minimum in February and a maximum generally in October or November. All 12 months show negative trends over the 35-yr period, with the largest magnitude monthly trend being the September trend, at -68 200 +/- 10 500 km(2) yr(-1) (-2.62% +/- 0.40% decade(-1)), and the yearly average trend being -35 000 +/- 5900km(2) yr(-1) (21.47% +/- 0.25% decade(-1)).