Sea ice extent on record low: In the Arctic it is too warm and too wet
„At the moment the situation in the Arctic is characterized by much warmer than usual temperatures (with more than 10°C above the mean value in the central Arctic) and by extremely low sea ice coverage, which has never been this low in February since the satellite measurements began“, emphasizes Prof. Christian Haas, head of the Sea Ice Physics section at AWI.
In February, the Arctic sea ice showed the lowest value ever observed for this month (see Figure 1), with a monthly average of 13.94 million km2. This value was even smaller compared to the sea ice coverage in February 2007 (14.51 million km2) and 2012 (14.25 million km2) – in both years the summer sea ice extent in September showed record lows. Besides, the observed value is also below the long-term two-fold standard deviation of the sea ice extent (Figure 2). The spatial distribution of sea ice cover shows a particularly low extent in the Bering Sea, on the East coast of Greenland, east of Spitsbergen and in the Barents Sea compared to the long-term mean (Figure 3). Especially dramatic was the loss of sea ice in the Bering Sea. There, the ice cover shrunk dramatically within a few days (Figure 3).

Figure 2: Daily sea ice extent until February 28, 2018 (red) in the Arctic. For comparison, the extent of 2016, 2012 and 2007 is shown, as well as the long-term average of 1981-2010 (gray) with the range of two standard deviations (light gray).

Figure 5: 925mb air temperature anomaly in January (left) and February (right) relative to the climatological mean: 1971 – 2000. (Source: www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html)

Figure 6: 850hPa geopotential height and wind vectors anomaly. Reference period: 1971-2000 (Source: www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html)

Figure 8: Time series of daily average air temperatures in January and February in Cape Morris Jesup (Greenland) and Berlin (Germany) (Source: Jesup data: www.dmi.dk; Berlin data: www.dwd.de)
Figure 9: Animation of the 30mb daily air temperature in February. (Source: www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html)
Figure 11: Animation of the daily 500mb geopotential height in February. (Source: www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html)
Figure 10: Animation of the daily integrated water vapor transport in February. (Source: www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html)
Graham, Robert M., Cohen, Lana, Petty, Alek A., Boisvert, Linette N., Rinke, Annette, Hudson, Stephen R., Nicolaus, Marcel, Granskog, Mats A.: Increasing frequency and duration of Arctic winter warming events, DOI: 10.1002/2017GL073395, Geophysical Research Letters, 2017. contact:
Prof. Dr. Christian Haas (Alfred-Wegener-Institut)
Dr. Monica Ionita-Scholz
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