My July 20 Arctic Forecasts

From July 20 :

My Arctic Forecasts | Real Science

That was exactly what happened. According to JAXA, from July 6 to July 20 the slope was -95,600 km^2 per day and from July 20 to August 2 the slope was -73,900 km^2 per day.

Then an early winter storm hit and the ice broke up.

About stevengoddard

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14 Responses to My July 20 Arctic Forecasts

  1. Richard T. Fowler says:

    Appreciate the reality check.


  2. Don Sutherland says:

    The Arctic storm likely acted as a catalyst for the decline in sea ice extent, but it is not clear that absent the storm, 2012 would not have received a record minimum. Prior to the storm, the rate of melt through July 31 from the spring maximum implied a record minimum.

    Following the storm, there was a dramatic increase in the rate of decline. The 8/6-8/2012 period saw a decline that was > 140% of the average for 2007-11 on each of those three days. The 15-day moving average also wound up more than 40% above the 2007-11 figure by 8/8. Afterward, there was a slowdown in the rate of decline relative to the 2007-11 average.

    However, after 8/15 another period of elevated decline relative to the 2007-11 timeframe took hold. For the most part, that elevated rate of decline has been sustained through 9/2. The average rate of decline for 8/16-9/2 was more than 63% above the average for 2007-11.

    Had the ice declined from its 7/31 figure at the average rate for 2007-11 through 8/15 and then at the rate that has held after 8/16, JAXA would still be at a record minimum today.

    • What is clear is that the most accurate measurements don’t show a “record minimum”

      • Warm says:

        “What is clear is that the most accurate measurements don’t show a “record minimum””

        new reality check for you:

        31-Aug-2012 2012244 4122141,18
        1-Sep-2012 2012245 4027497,41
        2-Sep-2012 2012246 3935061,38

      • pjie2 says:

        Hi Steve. That’s the same source that does MASIE, with the same methods, the only difference is that the operational charts (a) use a 10% cutoff for minimum extent, and (b) show where ice is expected, not just observed (i.e.they’re more cautious around the edge where wind changes may move ice into previously open water). We can thus presume that the differences with MASIE are largely down to very low concentration drift ice at ~10%-20% coverage.

        On Sept. 3rd 2012, this product shows 2,969,333 km^2 of consolidated pack ice (80%+) and 2,337,712 in the marginal ice zone (10-80%). On Sept 3rd 2007, it showed 3,750,485 km^2 of consolidated pack ice and 1,082,154 in the marginal zone. So, this year is still a little above 2007 for overall coverage of drift ice + pack ice combined, but very substantially below 2007 when you look at the thick pack ice.

        MASIE’s just dropped below 2007 record, so this one is the last shoe to drop. I’ll grant you that it’s a crap-shoot as to whether it actually does set a new record – however if the only way you can avoid a record is by conflating drift ice at 10-20% with pack ice at 80%+, I think that’s still a moral loss >.<

      • Julienne Stroeve says:

        Steve, check the MASIE value. It is now a record minimum too.

  3. Hugh K says:

    Just listen to yourself Don – “.likely..not clear…would not have…implied…for the most part….had the…would still be.”

    Now compare the above to Steven – “There will be…will flatten….that was exactly what happened.”

    Should be versus is….And that is a perfect example of the stark difference between alarmists and non-alarmists.

    • Julienne Stroeve says:

      Hugh, the rate of decline didn’t flatten however and August had the fastest rate of decline in the last 60 years of observations.

      • Julienne,

        You posted an excellent explanation for the rapid August decline. Thanks for that.

        About last weeks storm -Storm area 1 million square kilometers -Wave height of 2 to 3 meters broke apart ice into smaller chunks, increasing surface area and thus melting -Storm mixed fresh water at surface (from melted ice) with deeper warmer saltier water from below increasing melting rate -Storm agitated water to depths of 500 meters (where water is much warmer) bringing it to surface increasing melt rate -Low pressure of storm center sucked up water level by 0.3 meters, causing warm water to flow into Arctic Ocean from Pacific Ocean via Bering Strait and from Atlantic Ocean, increasing melting -Storm rotation (counterclockwise) spread out ice over larger area and pushed ice towards open ocean (on Atlantic Ocean side)

  4. Julienne Stroeve says:

    Steve, I would say there has not been a recovery in the summer sea ice since 2007. As for no change since 2007, the minimum is now falling outside the uncertainty of the estimate, so I would say that a new record low has occurred this year, reinforcing the overall negative trend in summer extent and volume.

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