Global Snow and Ice - September 2016
Beginning in November 2017, NCEI will use version 3 of the National Snow and Ice Data Center's (NSIDC) monthly sea ice extent index. All historical monthly sea ice extent values will be updated to version 3, but historical reports will not be updated. For additional information on the methodology changes and comparisons to version 2, please visit the National Snow and Ice Data Center.
Sea Ice Extent
|September 2016||Sea Ice Extent||
(out of 38 years)
|million km2||million mi2||Year(s)||million km2||million mi2|
Data Source: National Snow and Ice Data Center (NSIDC). Period of record: 1979–2016 (38 years)
According to the National Snow and Ice Data Center (NSIDC), the Northern Hemisphere (Arctic) sea ice extent — which is measured from passive microwave instruments onboard NOAA satellites — averaged for September 2016 was 4.72 million square km (1.82 million square miles), 1.82 million square km (710,000 square miles), or 27.83 percent, below the 1981-2010 average. This was the fifth smallest September Arctic sea ice extent on record, and was 1.09 million square km (420,000 square miles) larger than the smallest September Arctic sea ice extent that occurred in 2012. September was marked by sea ice retreat early in the month and sea ice expansion after the 10th when the annual minimum extent occurred. Sea ice expanded rapidly during the second half of September, especially in the Central Arctic and the East Siberian Sea. Regionally, below-average sea ice was observed for most of the Arctic with near-average sea ice in part of the Laptev Sea. September Arctic sea ice extent is decreasing at an average rate of 13.0 percent per decade.
On September 10th, Artic sea ice reached its annual minimum extent, five days earlier than average. The 2016 minimum was 4.14 million square km (1.60 million square miles), 2.08 million square km (800,000 square miles) below the 1981-2010 average, statistically tying the second smallest minimum Arctic sea ice extent that occurred in 2007. The 2016 minimum sea ice extent was 750,000 million square km (290,000 square miles) larger than the record smallest annual minimum extent that occurred in 2012. Large areas of open ocean that are typically ice covered in mid-September were observed on the 10th, including large areas of the Beaufort and Chukchi Seas on the Pacific side of the Arctic, and in the Laptev and East Siberian Seas on the Atlantic side.
The September Southern Hemisphere (Antarctic) sea ice extent was 18.45 million square km (7.12 million square miles), which was 380,000 square km (150,000 square miles), or 2.02 percent, below the 1981-2010 average. This was the fifth smallest September Southern Hemisphere sea ice extent on record and smallest since 2002. Southern Hemisphere September sea ice extent is increasing at an average rate of 0.90 percent per decade, with substantial inter-annual variability.
On August 31st, the Antarctic sea ice reached its maximum extent at 18.44 million square km (7.12 million square miles). This was the earliest occurrence of the maximum extent since satellite records began in 1979. This was the 10th smallest maximum extent for the Antarctic with sea ice 240,000 square km (93,000 square miles) larger than the average extent for the date. After the maximum extent occurred in late August, sea ice shrank early in September with the extent remaining nearly constant throughout the rest of the month.
For further information on the Northern and Southern Hemisphere snow and ice conditions, please visit the NSIDC News page.