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

Abstract

ell-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 km2 yr?1 (?2.62% ± 0.40% decade?1), and the yearly average trend being ?35 000 ± 5900 km2 yr?1 (?1.47% ± 0.25% decade?1).