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 trendsmore in line with the high-magnitude negativeArctic trends than the lower-magnitude positive Antarctic trends.Globally, monthly sea ice extent reaches aminimum in February and amaximumgenerally 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 268 200 6 10 500 km yr (22.62% 6 0.40%decade), and the yearly average trend being 235000 6 5900km yr (21.47% 6 0.25%decade).