Arctic Sea Ice September 2011

As of 4 Oct. 2011 the data coming from IJIS shows that the 2011 September Arctic sea ice was the second lowest on record, slightly above the record low for 2007.

Figure 5 shows the daily extent, figure 6 shows the daily change in extent (averaged over the prior week) and figure 7 compares the recent extents as a percentage of the 2003 – 2010 extent for the same day of the year. The data for this analysis were downloaded from “IJIS” (the IARC-JAXA Information System) reporting the AMSR-E sea ice extent on a daily basis since 2002.

Ice Fig. 5. Measured Extent

Ice Fig. 5. Measured Extent

Ice Fig. 6. Average Daily Change

Ice Fig. 6. Average Daily Change

Ice Fig. 7. Extent as a Percent of the Average Since 2003

Ice Fig. 7. Extent as a Percent of the Average Since 2003

From the National Snow and Ice Data Center (NSIDC) – September 2011 compared to past years

Figure 3. Monthly September ice extent for 1979 to 2011 shows a decline of 12.0% per decade.

Figure 3. Monthly September ice extent for 1979 to 2011 shows a decline of 12.0% per decade.

Ice extent for September 2011 was the second lowest in the satellite record for the month. The last five years (2007 to 2011) have had the five lowest September extents in the satellite record. The linear rate of decline is now -84,700 square kilometers (-32,700 square miles) per year, or -12% per decade relative to the 1979 to 2000 average. In contrast to 2007, when a “perfect storm” of atmospheric and ocean conditions contributed to summer ice loss, this year’s conditions were less extreme. From the beginning of the melt season in March, to the minimum extent on September 9, the Arctic Ocean lost 10.3 million square kilometers (4.0 million square miles) of sea ice. It was the fifth year in a row with more than 10 million square kilometers of ice extent change from maximum to minimum. In comparison, the average seasonal ice loss during the 1980s was 9.0 million square kilometers (3.5 million square miles)

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2 Responses to Arctic Sea Ice September 2011

  1. Alan Burke says:

    Unfortunately it looks like I’ll have to find another source for my Arctic Sea Ice Extent analysis. Reported by Nature News:

    Long-serving Earth observation sensor conks out – October 07, 2011

    The Advanced Microwave Scanning Radiometer-EOS (AMSR-E), a Japanese sensor on board NASA’s Aqua satellite, stopped transmitting data on 4 October following problems with antenna rotation.

    Scientists with the Japan Aerospace Exploration Agency (JAXA) and NASA are currently investigating the problem, but fear that the device might be permanently broken.

    Originally designed for a lifetime of just three years, AMSR-E has since 2002 continuously provided Earth scientists with valuable observational data on precipitation, oceanic water vapour, sea ice extent, sea surface temperatures, and soil moisture.

    More (Click here)


    Observation Halted by Advanced Microwave Scanning Radiometer-EOS (AMSR-E)

    The Japan Aerospace Exploration Agency (JAXA) has been operating the Advanced Microwave Scanning Radiometer-EOS (AMSR-E) for over nine years (despite a design life of three years) as an onboard device installed in the American earth observation satellite Aqua, after its launch on May 4, 2002. Since the end of August, 2011, however, the continuous increase of relatively large antenna rotation friction was detected twice, thus JAXA has been monitoring the condition. At 3:58 p.m. on October 4, 2011 (Japan Standard Time,) the AMSR-E reached its limit(*1) to maintain the rotation speed necessary for regular observations (40 rotations per minute), and the radiometer automatically halted its observations and rotation.

    JAXA will continue to analyze this problem, and take necessary measures to correct the situation. We will also launch the successor to the AMSR-E, the Global Change Observation Mission 1st- Water “SHIZUKU” (GCOM-W1.)

    *1) When rotation friction occurs, it is necessary to produce a turning force (torque) to offset the friction in order to maintain the rotation speed. The limit in this context means the maximum value of the torque (4.5 Nm,) which the AMSR-E’s motor can produce.

    More (Click here)

  2. Alan Burke says:

    See also: “Young and thin instead of old and bulky: researchers report on changes in Arctic sea ice after return of research vessel Polarstern

    In the central Arctic the proportion of old, thick sea ice has declined significantly. Instead, the ice cover now largely consists of thin, one-year-old floes. This is one of the results that scientists of the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association brought back from the 26th Arctic expedition of the research vessel Polarstern.

    The ship arrived at its home port of Bremerhaven at about 7 o’clock this morning. Prior to that it had covered more than 11,800 nautical miles on its 16-week research voyage and accommodated around 130 scientists from six countries on the three legs. The last stage took them through the central Arctic Ocean and the Polarstern also reached the North Pole. One of the most important research questions was: Did sea ice melt to a greater extent this summer, making it thinner than in past years?

    To answer it, the sea ice physicists headed by Dr Marcel Nicolaus and Dr Stefan Hendricks employed a measuring instrument called “EM Bird”. This nearly four-metre-long, torpedo-shaped probe is flown over the ice with a helicopter and measures the ice thickness by means of an electromagnetic induction method. In this way the sea ice physicists created an ice thickness profile of the central Arctic over a total distance of more than 2,500 flown kilometres. Their conclusion is: at sites where the sea ice was mainly composed of old, thicker ice floes in the past decades there is now primarily one-year-old ice with an average thickness of 90 centimetres. Only in the Canadian Basin and near the Severnaya Zemlya island group in northern Siberia did the sea ice physicists encounter significant amounts of several-year-old ice. As a rule, this old ice is between two and five metres thick.

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