Press release from the National Snow and Ice Data Center
Arctic sea ice extent for November 2019 ended up at second lowest in the 41-year satellite record. Regionally, extent remains well below average in the Chukchi Sea, Hudson Bay, and Davis Strait.
Overview of conditions
At the end of November and through the first week of December, daily extent was tracking third lowest in the satellite record, behind 2006 and 2016. Average ice extent for the month, however, finished second lowest in the passive microwave satellite record at 9.33 million square kilometers (3.60 million square miles). This was 670,000 square kilometers (259,000 square miles) above the 2016 record low for the month and 1.37 million square kilometers (529,000 square miles) below the 1981 to 2010 average. Regionally, extent remains well below average in the Chukchi Sea, as well as in Hudson Bay and Davis Strait. Extent is also below average in the Barents Sea, but not as pronounced as has been observed in recent years. Ice now extends to the shore along most of the Russian Arctic and along the coast of the Beaufort Sea. Extent is near average in the East Greenland Sea.
Conditions in context
The daily growth rate for November was generally steady, averaging 98,600 square kilometers (38,100 square miles) per day, compared to the 1981 to 2010 average of 69,600 square kilometers (26,900 square miles). Overall, ice extent increased by 2.75 million square kilometers (1.06 million square miles) through the month, somewhat larger than the 1981 to 2010 average for the month of 2.07 million square kilometers (799,000 square miles).
Average November air temperatures at the 925 hPa level (about 2,500 feet above the surface) were 2 to 4 degrees Celsius (4 to 7 degrees Fahrenheit) above average over the East Siberian, Beaufort, and Chukchi Seas, but near average or only slightly above average over the remainder of the Arctic Ocean. It was unusually warm, up to 6 degrees Celsius (11 degrees Fahrenheit) above average, over Greenland (Figure 2b). The warmth over the East Siberian, Chukchi, and Beaufort Seas is consistent with mean low pressure at sea level for the month centered north of East Siberian Sea, drawing in warmth from the south. Above average temperatures over the Chukchi Sea also reflect remaining areas of open water; indeed, at the surface, November temperatures in the Chukchi Sea were 10 to 12 degrees Celsius (18 to 22 degrees Fahrenheit) above average. Such high surface temperatures in this area will remain until the upper ocean losses its remaining heat and ice begins to form.
November 2019 compared to previous years
As assessed over the period of satellite observations, Arctic sea ice extent for November 2019 was 9.33 million square kilometers (3.60 million square miles), the second lowest in the satellite record. The linear rate of sea ice decline for November is 53,800 square kilometers (20,800 square miles) per year, or 5.02 percent per decade relative to the 1981 to 2010 average.
Ocean heat transport through Bering Strait
Recent work has shown that the transport of ocean heat into the Chukchi Sea through the Bering Strait strongly influences sea ice conditions in the region (Figure 4). This ocean heat transport, which is monitored by a buoy in the strait, depends on both the volume and temperature of this transported water. Recent work by C. Peralta‐Ferriz and R. Woodgate at the University of Washington in Seattle shows that variability in the volume inflow relates in considerable part to the strength of winds in the East Siberian Sea that act to raise or drop sea level in this area. A follow on paper by NSIDC scientists M. Serreze and A. P. Barrett, along with A. Crawford from Wooster College and R. Woodgate reveals that the winds in the East Siberian Sea that affect the Bering Strait inflow also relate to a broader atmospheric pattern of high versus low pressure over the central Arctic Ocean that influences September sea ice extent for the Arctic as a whole. Some recent large ocean heat transports through the Bering Strait are associated with high water temperatures, consistent with the persistence of open water in the Chukchi Sea into winter and early ice retreat in spring. The stubbornly slow freeze up in the Chukchi Sea this autumn may well reflect the effects of ocean heat transport.
Antarctic sea ice extent tracks the record minimum year
In the Antarctic, sea ice is in the midst of its sharp seasonal decline. It is currently tracking near 2017 levels, the record low year for minimum extent. November extent was 14.89 million square kilometers (5.75 million square miles), which is 1.01 million square kilometers (390,000 square miles) below the 1981 to 2010 average. It is the second lowest November extent in the satellite record, about 670,000 square kilometers (259,000 square miles) above November 2016.
Serreze, M. C., A. P. Barrett, A. D. Crawford and R. A. Woodgate. 2019. Monthly variability in Bering Strait oceanic volume and heat transports, links to atmospheric circulation and ocean temperature, and implications for sea ice conditions. Journal of Geophysical Research Oceans, November 11, 2019, doi:10.1029/2019JC015422.
Date of publication: 5 Dec 2019
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