Satellite data provide insight into melting Arctic ice

In September 2012, the smallest ice spread to date in the Arctic was recorded. With data from satellites, scientists at SMHI have analysed changes in the atmosphere, and then compared the conditions for the ice melt in 2012 with 2007, the previous record low for ice spread.

“Satellite-based monitoring of the atmosphere can be an important source of knowledge in predicting extreme ice melts in the Arctic region,” says Abhay Devasthale, a scientist in atmospheric remote sensing at SMHI.

Meteorological conditions

Three changes in the meteorological conditions were likely important factors in the low ice spread:

  • Ice did not build up as much as normal during the winter and early spring of 2012, as the ice zones in the Euro-Asiatic and North Atlantic areas were warmer than normal.
  • Ocean circulation patterns meant that more ice than normal was carried from the Arctic to the Atlantic Ocean during the spring and early summer of 2012.
  • Warming over the Canadian archipelago and the south-east Beaufort Sea north of Alaska from May and over summer 2012 was probably also a factor.

“These factors jointly could have led to the already thin, decreasing ice in the Arctic falling below its previous minimum,” says Devasthale.

On analysing satellite data, the scientists also observed negative temperature deviations at the surface and increased cloudiness over parts of the Arctic Ocean north of Russia (the East Siberian Sea and the Chukchi Sea) during summer 2012, something that could not be seen in 2007.

Arctic iceconcentration 2007 and 2012
Observed ice concentration in the Arctic, 31 July 2007 and 2012 respectively. Regions in the Arctic with accelerated ice melt are marked red (2007) and yellow (2012). © Atmospheric Chemistry and Physics. Enlarge Image

Downward trend

The ice in the Arctic region is growing younger and younger, as more ice melts during the warm season and less is built up during the cold season. For the period 1979-2010 there is a clear downward trend when it comes to the ice spread. However, as the ice spread has reached new record lows, these years have so far been followed by years of recovery and ice growth. The general trend for the overall ice volume has, however, been a decline.

The study is funded by the Swedish National Space Board and conducted by scientists at SMHI with the help of data from Atmospheric Infrared Sounder (AIRS) instruments aboard the satellite Aqua, which can make full-scale 3D information for thermodynamics available, as well as data from the ECMWF data portal for winds.