The extremely low Antarctic sea ice extent for most of the year was the most noteworthy characteristic of either polar region for 2023. Below average conditions prevailed over Wilkes Land, at 1 to 2 degrees Celsius (2 to 4 degrees Fahrenheit) below the 1991 to 2020 reference period. Dronning Maud Land was above average by up to 2.5 degrees Celsius (4.5 degrees Fahrenheit). Air temperatures were above average over West Antarctica and the Ross Sea by 1 to 3 degrees Celsius (2 to 5 degrees Fahrenheit) for the month, and over the Bellingshausen Sea by 1 to 2 degrees Celsius (2 to 4 degrees Celsius) (Figure 5c). Low sea ice concentrations in the Ross Sea and western Amundsen Sea portend upcoming ice extent declines in these areas. Typical for this time of year, a large polynya has opened up in front of the Ross and Sulzberger Ice Shelves. Despite the slow ice loss, few areas of the Southern Ocean have above average sea ice extent, and extent is still well below the average for 1981 to 2010 in the Weddell Sea, along the coast of Dronning Maud Land, and in the western Ross Sea (Figure 5b). As a result, by the beginning of the new year, extent was only sixth lowest (Figure 5a). However, the seasonal decline in Antarctic ice extent subsequently slowed. Yellows and reds indicate above average temperatures blues and purples indicate below average temperatures.Īt the beginning of December, ice extents were at record low levels. This plot shows the departure from average air temperature in the Arctic at the 925 hPa level, in degrees Celsius, for December 2023. December 2023 compared to previous yearsįigure 5c. This pattern led to cold Arctic air flowing across the Chukchi Sea and into the Bering Sea as well as advection of relatively warm air across Canada into the Beaufort Sea. The atmospheric circulation pattern for December was marked by low sea level pressure over the Gulf of Alaska and northern Europe and high sea level pressure over central Russia (Figure 2b). By contrast, the warm conditions over Hudson Bay, continuing since November, explain its delayed start of ice formation there. Cool conditions in the Bering and southern Chukchi Seas explain the rapid ice growth there. Elsewhere, relatively cool conditions prevailed, with air temperatures 2 to 4 degrees Celsius (4 to 7 degrees Fahrenheit) below average in southwestern Alaska, easternmost Russia, Scandinavia, and southeast Greenland. Warm conditions prevailed over the central Arctic Ocean and Beaufort Sea regions, as well as over Hudson Bay and much of northern Canada, with air temperatures at the 925 millibar level (around 2,500 feet above sea level) 8 to 9 degrees Celsius (14 to 16 degrees Fahrenheit) above the 1991 to 2020 average (Figure 2a). Yellows and reds indicate above average air pressures blues and purples indicate below average air pressures.Ĭredit: NSIDC courtesy NOAA Earth System Research Laboratory Physical Sciences Laboratory This plot shows average sea level pressure in the Arctic in millibars for December 2023. After a delayed start to the freeze-up in Hudson Bay, sea ice formed quickly from west to east across the bay, leaving only a small area of open ocean near the Belcher Islands at month’s end. In the northern Atlantic, sea ice extent remained below average extent, as has been typical for the past decade.įor December overall, 2023 had the third highest monthly gain in the 45-year record at 2.71 million square kilometers (1.05 square miles), behind 2006 at 2.85 million square kilometers (1.10 million square miles) and 2016 at 2.78 million square kilometers (1.07 million square miles). Sea ice extent increased by an average of 87,400 square kilometers (33,700 thousand square miles) per day, markedly faster than the 1981 to 2010 average of 64,100 square kilometers (24,700 square miles) per day (Figure 1b). Sea Ice Index data.Ĭredit: National Snow and Ice Data CenterĪverage Arctic sea ice extent for December 2023 was 12.00 million square kilometers (4.63 million square miles), ninth lowest in the 45-year satellite record (Figure 1a). The gray areas around the median line show the interquartile and interdecile ranges of the data. The graph above shows Arctic sea ice extent as of January 3, 2024, along with daily ice extent data for four previous years and the record low year.
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