4
In addition, the ice pack has become more mobile (Spreen et al. 2011) which will
result in more frequent pressure ridge formation (Wadhams and Toberg 2012). The
thinning of the Arctic ice pack has also increased the amount of sunlight reaching
the ocean (Nicolaus et al. 2012), with consequences for increased primary production beneath sea ice (Arrigo et al. 2012). Changes in snow depth, have been documented in the western Arctic, assumed to be caused by less snow fall on first-year
sea ice forming later in the season (Webster et al. 2014). However, on the other hand
precipitation in the Arctic could increase partly due to sea-ice retreat (Bintanja and
Selten 2014).
Here we document some recent observations from the Norwegian young sea ICE
expedition (N-ICE2015) on the characteristics of the Arctic ice pack in the Atlantic
sector of the Arctic (Granskog et al. 2018). These rare observations show some
emerging new features that are likely a response to the changes in sea ice, which is
now more sensitive to both atmospheric and oceanic forcing.
2 Emerging Properties of the (Now Seasonal) Arctic Ice Pack
Like elsewhere in the Arctic, the ice thickness has decreased in the Atlantic sector
(the Transpolar Drift), and this is quite well documented with one of the longest ice
thickness time-series in the Arctic (Hansen et al. 2013). More recent work supports
this trend (Rösel et al. 2018). In the 1990s the ice was about 3 m thick, while now it
is closer to 2 m thick (Fig. 1). This has been attributed both to atmospheric warming
Fig. 1 Monthly mean and modal sea ice thickness in the Fram Strait. Gaps in the time-series
indicate missing data. (Updated from data in Hansen et al. 2013. Data available at http://www.
mosj.no/)
M. A. Granskog et al.
In addition, the ice pack has become more mobile (Spreen et al. 2011) which will
result in more frequent pressure ridge formation (Wadhams and Toberg 2012). The
thinning of the Arctic ice pack has also increased the amount of sunlight reaching
the ocean (Nicolaus et al. 2012), with consequences for increased primary production beneath sea ice (Arrigo et al. 2012). Changes in snow depth, have been documented in the western Arctic, assumed to be caused by less snow fall on first-year
sea ice forming later in the season (Webster et al. 2014). However, on the other hand
precipitation in the Arctic could increase partly due to sea-ice retreat (Bintanja and
Selten 2014).
Here we document some recent observations from the Norwegian young sea ICE
expedition (N-ICE2015) on the characteristics of the Arctic ice pack in the Atlantic
sector of the Arctic (Granskog et al. 2018). These rare observations show some
emerging new features that are likely a response to the changes in sea ice, which is
now more sensitive to both atmospheric and oceanic forcing.
2 Emerging Properties of the (Now Seasonal) Arctic Ice Pack
Like elsewhere in the Arctic, the ice thickness has decreased in the Atlantic sector
(the Transpolar Drift), and this is quite well documented with one of the longest ice
thickness time-series in the Arctic (Hansen et al. 2013). More recent work supports
this trend (Rösel et al. 2018). In the 1990s the ice was about 3 m thick, while now it
is closer to 2 m thick (Fig. 1). This has been attributed both to atmospheric warming
Fig. 1 Monthly mean and modal sea ice thickness in the Fram Strait. Gaps in the time-series
indicate missing data. (Updated from data in Hansen et al. 2013. Data available at http://www.
mosj.no/)
M. A. Granskog et al.