Minimum bedekking zeeijs noordelijk halfrond dit jaar op 19 en 23 semptember 2018

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Martijn
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Lid geworden op: Ma 1 Nov 2010, 21:56
Locatie: Gaasterland, Friesland

Minimum bedekking zeeijs noordelijk halfrond dit jaar op 19 en 23 semptember 2018

Berichtdoor Martijn » Di 9 Okt 2018, 15:48

In januari en februari van dit jaar was de ijsbedekking op het noordpoolgebied recordlaag voor die maanden, en september 2018 eindigt met september 2008 op een gedeelte 6e plek van de laagste zeeijsbedekking in september. De minimum omvang werd bereikt op 19 en 23 september 2018. 23 september zit bij de laagste dagen van het jaar voor het seizoensminimum van bijna 40 jaar satellietmetingen. In het zuidpoolgebied lijkt de jaarlijkse maximum omvang van het zeeijs op 2 oktober 2018 te zijn bereikt.

Hieronder staan gedeelten van een artikel van het NSIDC wat hierover gaat, met enkele afbeeldingen. Zie bron voor volledig artikel met nog meer afbeeldingen.

Bron: https://nsidc.org/arcticseaicenews/2018 ... th-lowest/

Arctic summer 2018: September extent ties for sixth lowest

October 8, 2018

After starting the year with record lows in January and February, Arctic sea ice extent ended tied with 2008 for the sixth lowest average September extent in the satellite record. The 2018 minimum extent was reached on both September 19 and 23. September 23 is among the latest dates for the seasonal minimum in the nearly 40-year satellite record. In the Antarctic, the annual maximum extent appears to have been reached on October 2.

2018-10-09-1504_Figure1.png
Figure 1. Arctic sea ice extent for September 2018 was 4.71 million square kilometers (1.82 million square miles). The magenta line shows the 1981 to 2010 average extent for the month.

Credit: National Snow and Ice Data Center
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Overview of conditions

Arctic sea ice extent for September 2018 averaged 4.71 million square kilometers (1.82 million square miles), tying with 2008 for the sixth lowest September in the 1979 to 2018 satellite record. This was 1.70 million square kilometers (656,000 square miles) below the 1981 to 2010 average, and 1.14 million square kilometers (440,000 square miles) above the record low recorded for September 2012. Prior to September 19, sea ice extent declined at a relatively rapid 14,440 square kilometers (5,580 square miles) per day, significantly faster than in most years. The near-zero loss rate between September 19 and 23, and the very late onset of significant seasonal ice growth after September 23, were atypical of the satellite record.

Sea ice loss during the first half of September primarily occurred within the East Siberian, northern Laptev, and northern Chukchi Seas, in part because winds from the south brought warm air into the region and inhibited ice from drifting or growing southward. Retreat in these areas was partially offset by ice expansion in the eastern Beaufort Sea and the northern Kara and Barents Seas. The old ice that had been persisting in the Beaufort Sea near Prudhoe Bay mostly melted out by the end of September. While the Northern Sea Route opened again this year, as it has every year since 2008, ice lingered in the central section of the southern route of the Northwest Passage between Bellot Strait and Gjoa Haven.

Since the seasonal minimum extent, reached on September 19 and again on September 23 at 4.59 million square kilometers (1.77 million square miles), ice cover has expanded in the Canadian Archipelago, the northern Chukchi and Beaufort Seas, and the East Greenland Sea, while retreating slightly within the Kara Sea.

2018-10-09-1508_Figure2_10072018.png
Figure 2a. The graph above shows Arctic sea ice extent as of October 07, 2018, along with daily ice extent data for four previous years and the record low year. 2018 is shown in blue, 2017 in green, 2016 in orange, 2015 in brown, 2014 in purple, and 2012 in dotted brown. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data.

Credit: National Snow and Ice Data Center
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(...)

September 2018 compared to previous years

Sea ice extent for September 2018 fell just above the long-term linear trend line. The linear rate of sea ice decline for September is 82,300 square kilometers (32,000 square miles) per year, or 12.8 percent per decade relative to the 1981 to 2010 average.

2018-10-09-1508_Figure3.png
Figure 3. Monthly September ice extent for 1979 to 2018 shows a decline of 12.8 percent per decade.

Credit: National Snow and Ice Data Center
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