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Canadian Ice Service

Key Points and Details concerning the

2009 Arctic Minimum Summer Sea Ice Extent

October 1st, 2009

http://ice-glaces.ec.gc.ca

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Key Points of Interest

Arctic-wide

The Arctic-wide minimum sea ice extent at the end of August 2009 was similar to that of 2008(i.e. slightly greater than the record minimum set in 2007), but the spatial distribution of theice was different. There was more ice in the southern Beaufort Sea than in 2008, but therewas less ice in the Laptev Sea than in 2008.

Although still well below the 1979-2008 30-year normal extent of 6.6 million squarekilometers, the minimum Arctic sea ice extent at the end of the 2009 summer melt season(~5.1 million square kilometers achieved on September 12th) is slightly greater than that in2008 (4.7 million square kilometers). Since both the 2008 and 2009 ice coverages exceededthat of 2007 (4.3 million square kilometers), it is possible that the record minimum conditionsthat occurred in 2007 may have been more of an extreme variation about a smaller negativetrend as opposed to a significant acceleration in Arctic sea ice loss.

Canada

In the western Canadian Arctic, ice concentrations at the end of August were near to slightlybelow normal.

Greater than normal concentrations of ice occurred in the south-eastern Beaufort Sea due toperiods of northerly winds, which carried some of the multi-year pack ice southwards into thisarea during the melt season.

In the Northwest Passage, ice concentrations were near to greater than normal in westernsections, near normal in central sections, and less than normal in eastern sections.

Greater than normal concentrations of ice in the central and western parts of the NorthwestPassage in July and August led to a delay in navigability of the southern route, while thenorthern route did not become truly navigable at all this year. This situation is similar to 2006,a year in which the southern route was passable but the northern route remained clogged withice. By contrast, both routes were navigable in the summers of 2007 and 2008.

In the eastern Canadian Arctic, ice concentrations were for the most part well below normal(although they did not set a record). This was due to an early clearing of Nares Strait,northern Baffin Bay and Lancaster Sound.

In Hudson Bay, greater than normal concentrations of ice (due to colder than normal airtemperatures in June, July and August) lingered in the southern sections until the end ofAugust, when normally the area would have been clear of ice by mid-August.

In the farthest north of Canada, along the north coast of Ellesmere Island, there were nofurther losses to the ice shelves and no new ice islands. This is primarily because no openwater lead developed this year between the coast of Ellesmere Island and the pack ice in theArctic Ocean.

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Table of Contents

1. The Arctic Ocean ......................................................................................................... 4

Background: Summers of 2007 and 2008 .................................................................. 4

CIS Outlook for 2009.................................................................................................... 4

End-of-Melt-Season 2009 Arctic Sea Ice Conditions (Verification of CIS Outlook)......................................................................................................................................... 5

2. The Canadian Arctic: end-of-melt-season 2009 details ............................................. 8

Western Arctic: General ................................................................................................ 8

Western Arctic: Beaufort Sea ........................................................................................ 9

Northwest Passage ....................................................................................................... 11

Eastern Arctic: General ............................................................................................... 15

Eastern Arctic: Nares Strait ....................................................................................... 16

Eastern Arctic: Lancaster Sound and northern Baffin Bay ..................................... 21

Eastern Arctic: Davis Strait ........................................................................................ 22

Eastern Arctic: Petermann Ice Island........................................................................ 26

Northern Ellesmere Ice Shelves and Ice Islands ........................................................ 27

Hudson Bay .................................................................................................................. 29

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1. The Arctic Ocean

Background: Summers of 2007 and 2008

The Arctic summer minimum sea ice extent observed in September 2007 (4.3 millionsquare kilometers) broke all records (note that most records span only 30-40 years) andwas well below all model predictions. As a result, scientists speculated at the time thatthe observed negative trend in Arctic summer sea ice extent could be accelerating. Theminimum Arctic sea ice extent in September, 2008 (4.7 million square kilometers),however, was slightly greater than that of 2007, as a result of a large area of first-year icesituated over the North Pole that did not melt as anticipated (although overall summer seaice thicknesses were less in 2008 than in 2007).

CIS Outlook for 2009

Due to the uncertainties introduced by the summers of 2007 and 2008 regarding anypossible acceleration in the trend, in June, 2009, the Canadian Ice Service forecast a 2009Arctic minimum sea ice extent of 5 million square kilometers (similar to but slightlygreater than that of 2008). This value was based on: 1) the amount of thick multi-year iceremaining in the Arctic Ocean at the end of May 2009, which was similar to, but slightlyless than, the amount remaining at the end of May 2008; 2) the fact that many areas of theCanadian Arctic experienced greater than normal ice concentrations and thicknessesduring the winter of 2008-2009; and 3) the fact that a large area of first-year ice did notmelt as predicted over the north pole in the 2008 melt season.

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End-of-Melt-Season 2009 Arctic Sea Ice Conditions (Verification of CIS Outlook)

The Arctic-wide minimum sea ice extent at mid-September 2009 was similar to that of2008 (i.e. slightly greater than the record minimum set in 2007), but the spatialdistribution of the ice was different. There was more ice in the southern Beaufort Seaand the East Greenland waters than in 2008, but there was less ice in the Laptev Sea thanin 2008.

Figure 1. Ice concentration chart produced at CIS using a combination of AMSR-E satellite imagery andice chart data. Periods of northerly winds drove the multi-year pack ice southwards into the southeasternBeaufort Sea during the melt season, leading to greater than normal concentrations in this area this summer(in 2009).

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Although still well below the 1979-2008 30-year normal extent of 6.6 million squarekilometers, the minimum Arctic sea ice extent at the end of the 2009 summer melt season(~5.1 million square kilometers) is slightly greater than that in 2008 (4.7 million squarekilometers). Since both the 2008 and 2009 ice coverages exceeded that of 2007 (4.3million square kilometers), it is possible that the record minimum conditions thatoccurred in 2007 may have been more of an extreme variation about a smaller negativetrend as opposed to a significant acceleration in Arctic sea ice loss.

Year / Month August September2000 7.21 6.322001 7.47 6.752002 6.53 5.962003 6.85 6.152004 6.83 6.052005 6.30 5.572006 6.52 5.922007 5.36 4.302008 6.06 4.672009 6.26 5.10

Table 1. Arctic sea ice extent based on monthly data from NSIDC. Ice extents are in millions of squarekilometers.

Figure 2. Trend in NSIDC September sea ice extent anomalies showing 2009 > 2008 > 2007 (Figure takenfrom the NSIDC web page – data derived from Nimbus-7 SSMR and DMSP SSM/I Passive MicrowaveData sets).

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Figure 3. NSIDC sea ice extent (as of 30 Sept. 2009) derived from Nimbus-7 SSMR and DMSP SSM/IPassive Microwave Data.

Figure 4. CIS sea ice extent derived using a combination of AMSR-E satellite imagery and ice chart data.

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2. The Canadian Arctic: end-of-melt-season 2009 details

Western Arctic: General

Ice concentrations in the western Canadian Arctic in the 3rd week of September, 2009,were near to slightly below the 1971-2000 normal.

Figure 5. Bar graph showing ice coverages for the date of September 24, for the years of 1968 to thepresent (2009), in the western Canadian Arctic.

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Western Arctic: Beaufort Sea

In 2009, the Beaufort Sea ice coverage for early-September was greater than thatobserved in 2007 and 2008. Periods of northerly winds drove the multi-year pack icesouthwards into the southeastern Beaufort Sea during the 2009 melt season, leading togreater than normal concentrations in parts of this area.

Note that while 2007 was a record minimum ice coverage year for the whole Arctic, itwas not a record year for the Canadian Arctic. For the Beaufort Sea, 2008 representedthe new record year, breaking the old record set in 1998.

Figure 6. Bar graph showing ice coverages for the date of September 24, for the years of 1968 to thepresent (2009), in the Beaufort Sea.

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Figure 7. Ice concentrations at mid-September, 2009, were greater than normal in southeastern parts of theBeaufort Sea, due to periods of northerly winds, which carried some of the remaining multi-year pack icesouthwards into this area during the melt season.

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Northwest Passage

In the Northwest Passage, ice concentrations were near to greater than normal in westernsections, near normal in central sections, and less than normal in eastern sections.Greater than normal concentrations of ice in the central and western parts of theNorthwest Passage in July and August led to a delay in navigability of the southern route,while the northern route did not become navigable at all in 2009. This situation is similarto 2006, a year in which the southern route was passable but the northern route remainedclogged with ice. By contrast, both routes were navigable in the summers of 2007 and2008.

Figure 8. Average total accumulated ice coverage along the entire length of the Northwest Passage(southern route) for the period of May 14 to September 24, for the years 1968 to 2009.

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The consolidation of the ice in Amundsen Gulf over the past winter, along with colderthan normal air temperatures in June and July, led to a delay in ice melt in the westernpart of the southern route of the Northwest Passage.

Figure 9. Colder than normal air temperatures in June and July contributed to a delay in ice melt in thesouthern route of the Northwest Passage this year (2009). In the Beaufort Sea, northerly winds pushed themulti-year ice pack southwards during the melt season, creating areas of greater than normal iceconcentrations (where blue denotes greater than normal concentrations on CIS charts and red denotes less).

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The influx of Arctic multi-year ice into the passages between the Canadian ArcticArchipelago last summer (2008) led to the blockage of Viscount Melville Sound andM’Clintock Channel this summer (2009). As a result, the northern route of the NorthwestPassage was not navigable and the central part of the southern route (Larsen Sound) hadlimited navigability due to the presence of multi-year ice and an associated delay in themelt of the first-year ice in the area.

Figure 10. Left: CIS ice charts for the first week of December, 2008 (top: coloured for concentration,where red indicates mobile ice and grey indicates consolidated or fast ice; bottom: coloured for ice type,where red-brown indicates multi-year ice and green indicates first-year ice). Right: Ice chart showing thedeparture-from-median concentration of old ice in August, 2009 (where blue indicates greater than normalconcentrations and red indicates less).

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Figure 11. Ice concentration chart produced at CIS using a combination of AMSR-E satellite imagery andice chart data, showing ice conditions in the Northwest Passage at the end of August. The northern andsouthern routes of the Northwest Passage are indicated in pink.

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Eastern Arctic: General

In the eastern Canadian Arctic, ice concentrations in early September were for the mostpart well below the 1971-2000 normal (although they did not set a record). This was dueto an early clearing of Nares Strait, northern Baffin Bay and Lancaster Sound.

Figure 12. Bar graph showing yearly ice coverage for the date of September 24, from 1968 to the present(2009), in the eastern Canadian Arctic.

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Eastern Arctic: Nares Strait

An anomalous, persistent ice arch at the north end of Nares Strait developed in February(as a result of high ice pressures / shoreward ice convergence in the Lincoln Sea) andbroke in July. Along with persistent northerly winds, this created polynya-like conditionsalong the entire length of the Strait throughout the winter months. That is, the Strait didnot consolidate as per normal. As a result, ice clearing in this area was much earlier thannormal. Nares Strait became ice free in May, except for areas of shore-fast ice inadjoining bays and fiords, and remained so until mid-July when the ice arch finally broke,allowing multi-year ice from the Arctic to invade the strait once again. Once the ice archbroke in July, the influx of Arctic multi-year ice led to greater than normal iceconcentrations in the Strait during the rest of the summer.

Figure 13. Modis image for June 26, 2009, showing an ice-free Nares Strait. A well-defined ice arch canbe seen indenting into to Arctic multi-year ice pack in the Lincoln Sea at its northern end. A large piece offreshly broken-off shore-fast sea ice, originally attached to the front of the Petermann Glacier, is circled inpink.

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Figure 14. Modis image for July 17, 2009, showing the initial influx of Arctic multi-yearice into Nares Strait, after the fracture of the ice arch at its northern end. Fracturing ofthe arch began July 6, and ice began to enter the strait on July 14.

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Figure 15. Meris image (copyright ESA, 2009) for August 04, 2009, showing extensive Arctic multi-yearice amounts in Nares Strait.

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Figure 16. Departure from normal concentration ice charts showing: a) less than normal total iceconcentrations in June in Nares Strait; and b) greater than normal old ice concentrations in August.

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Additional facts:

o Normally, the ice in Nares Strait consolidates between February and July (basedon 1971-2000) CIS ice chart data), blocking the flow of Arctic Multi-year ice(MYI) into Baffin Bay and the North Atlantic for half the year. This allows forthe formation of the North Open Water polynya at the southern end of the Strait,an area of thin ice and/or open water that is biologically important to manyspecies.

o 2009 is only the second year in the CIS ice chart record in which Nares Strait didnot consolidate (the other year being 2007).

o In 2007, however, no permanent ice arch formed at the north end of the Strait andthis led to anomalously greater-than-normal amounts of thick, multi-year iceflowing from the Arctic Ocean into Baffin Bay throughout the winter months(some of which eventually reached Newfoundland waters in April of that year).

o In 2009, a permanent ice arch formed at the north end of the Strait in the LincolnSea, blocking the flow of multi-year ice from the Arctic Ocean into Baffin Bayand allowing for the formation of a latent-heat type polynya along the wholelength of the strait in the winter, leading to the early clearing of all ice in May.

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Eastern Arctic: Lancaster Sound and northern Baffin Bay

This year (2009), the ice in Lancaster Sound and northern Baffin Bay broke up andcleared at around the end of May / beginning of June. Normal break-up dates (accordingto the CIS 1971-2000 Climatological Sea Ice Atlas for Northern Waters) are betweenJune 18 and July 16 for the eastern and western parts of Lancaster Sound, respectively.Normal break-up / clearing dates for northern Baffin Bay are near July 02.

The early clearing of these areas was related to the fact that neither Lancaster Sound norNares Strait ice consolidated this past winter. While this was very unusual for NaresStrait, it is not particularly unusual for the ice in Lancaster Sound to remain mobilethroughout some winters. Persistent northerly winds over Nares Strait throughout thewinter/spring period and a period of strong northwesterly winds over western parts ofLancaster Sound in May then helped to clear these areas of ice 3-6 weeks earlier thannormal.

Figure 17. Left: Departure from normal ice concentration chart for June, 2009, showing the early clearingof ice for Lancaster Sound and northern Baffin Bay (areas in blue circles). Right: NCEP/NCAR vectorwind anomaly plot for May, 2009, showing stronger than normal northwesterly winds in eastern BarrowStrait and western Lancaster Sound.

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Eastern Arctic: Davis Strait

Greater than normal concentrations of ice lingered in Davis Strait well into August, thisyear.

Air temperatures were near to greater than normal in this area in June and July andprobably did not play a role in maintaining the anomalous ice conditions in this area.

Sea surface salinities, on the other hand, were below normal, as were sea surfacetemperatures. Fresher (and therefore less dense) surface waters restrict the mixing ofcolder surface waters with warmer waters beneath. Restricted vertical mixing of seawater, due to fresher surface waters, therefore likely: 1) promoted some additional icegrowth during the March to May period in this area, when air temperatures were stillbelow freezing; and 2) helped maintain colder sea surface temperatures into thebeginning of the melt season, slowing the ice melt in the area.

Figure 18. Bar graph of ice coverage for the Davis Strait region for the date of August 13, over the periodof 1971 to 2009. Ice coverage on August 13, 2009, was greater than it was for that same date over theprevious 13 years.

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Figure 19. Departure from normal concentration sea ice charts for various weeks spanning March toAugust, 2009, showing greater than normal ice concentrations in the Davis Strait area (red-circled areas).

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Figure 20. NCEP/NCAR reanalysis surface air temperature anomaly for June/July/August 2009.

Figure 21. Air temperature reported at Iqaluit for the period of June 01 to August 31, 2009.

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Figure 22. A vertical salinity profile for southern Davis Strait area recorded by an ARGO buoy for August19, 2009 (green line) plotted against a climatological salinity profile for the area (blue line). Surfacesalinities in 2009 (32.65 PSU) are currently less than the climatological normal for this area (~33.00 PSU).

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Eastern Arctic: Petermann Ice Island

The Petermann Ice Island, a large tabular iceberg that broke off the Petermann Glacier innorthern Greenland in July, 2008, drifted southwards to reach the mouth of Frobisher Bayby June, 2009. It then disintegrated into numerous small fragments.

Figure 23. Left: The track of the Petermann Ice Island (determined from satellite imagery and via atracking beacon deployed on the ice island). Right: Observed positions and a picture of some of thenumerous ice island fragments seen at the mouth of Frobisher Bay following the break-up of the Ice Island.

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Northern Ellesmere Ice Shelves and Ice Islands

No further losses to the northern Ellesmere Island ice shelves occurred in 2009, and nonew ice islands were created. This is probably related to the fact that no period ofpersistent offshore winds developed in 2009 and, as a result, no open water leaddeveloped between the Ellesmere Island coast and the Arctic pack ice this year. June toAugust surface air temperatures were 1ºC to 2.5 ºC above normal (similar to 2008).

The leading edge of the Beaufort Sea ice island pack, created during July and August,2008, from the break-up of the northern Ellesmere Ice Shelves, now reaches south of80ºN to Borden Island. Some of the ice islands have also entered the Canadian ArcticArchipelago via the Sverdrup and Peary Channels.

The remains of the 2005 Ayles Ice Island, now in at least 4 fragments if not more, aremostly located in Penny Strait and Queens Channel, although one remains to the east orsoutheast of Amund Ringnes Island.

Figure 24. Pink circle: location of the Ellesmere Island ice shelves. White circle: current distribution ofthe 2005 and 2008 ice islands.

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Figure 25. June to August, 2009, surface air temperature anomalies over Ellesmere Island (fromNCEP/NCAR reanalysis data). The Eureka weather station established record-breaking temperatureanomalies in July and August of 2009.

Figure 26. Bar chart showing the number of weeks an open water lead existed between the northernEllesmere Island coast and the Arctic pack ice, for the summers of 1997 to 2008.

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Hudson Bay

In Hudson Bay, greater than normal concentrations of ice lingered in the southernsections until the end of August (3-4 weeks later than normal). Normally the area wouldhave been clear of ice by mid-August. The persistence of the ice was related to colderthan normal air temperatures and cloudier-than-normal skies (less sun means less melt) inJune, July and August. The frequency of presence of sea ice in this area at the end ofAugust is normally less than 15%.

Figure 27. Bar graph showing the total accumulated ice coverage for central and southwestern HudsonBay, for the period May 14 to September 03, for the years 1971 to 2009.

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Figure 28. Departure from normal ice concentrations in Hudson Bay on August 10, 2009.

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Figure 29. Top: A series of CIS weekly regional ice charts showing anomalous ice patches in southernHudson Bay throughout August, 2009. Bottom: A median ice concentration chart for the week of August13 (taken from the CIS 1971-2000 Climatological Sea Ice Atlas for northern waters) showing no ice in thisarea in the middle of August.

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Figure 30. NCEP/NCAR reanalysis data showing colder than normal air temperatures and cloudier thannormal skies over southern Hudson Bay for the period June-August, 2009.