NOAA Showing 14 % More Ice Than The 2007 Minimum

[correction – I originally said 18% but had copied the number over incorrectly from my spreadsheet]

Turquoise represents ice present in 2012 which wasn’t present at the 2007 minimum. Red shows the opposite. There is 14% more ice than there was at the 2007 minimum.

http://www.natice.noaa.gov/pub/ims/ims_gif/DATA/cursnow_alaska.gif

ims2007262_alaska.gif (512×512)

Very little change has occurred north of 80N over the last few days.

About Tony Heller

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39 Responses to NOAA Showing 14 % More Ice Than The 2007 Minimum

  1. Thierry says:

    Hi Steve,
    It looks like ice has been increasing these past two days according to DMI, with new scattered ice filling up most if the open sea in the Arctic.
    http://ocean.dmi.dk/arctic/satellite/index.uk.php
    It may turn out that we will assist to a very fast sea freezing soon.

  2. squid2112 says:

    Oh come on Steve, this can’t be true. You just drove up there in the middle of the night and painted that on there. Fooling the satellites again… sheeesh…

  3. fishnski says:

    Watching the beginnings of the snowpack forming both in siberia and the canadien arctic islands…hoping for a dramatic re freeze up.

  4. pjie2 says:

    August 19th: 40% more
    August 25th: 36% more
    August 27th: 28% more
    August 28th: 22% more
    August 29th: 18% more

    … to be continued …

    P.S. Spotting a trend yet? I reckon you’ll be eating crow in about a week.

    P.P.S. I’m not quite sure why your numbers are different from the ones Julienne gives (4.26 million today, 3.99 for 2007 minimum, i.e. a difference of 6.8%). I’d hazard a guess that it’s due to you counting from a downsampled low-resolution picture and/or not accounting for any effects due to the stereographic projection.

  5. David Sanger says:

    How are you calculating your 18% figure Steve?

  6. David Sanger says:

    It would be helpful if you gave the link to the actual image for today; rather than the cursnow_alaska.gif it’s better to use the actual gif with the year and day of year eg. http://www.natice.noaa.gov/pub/ims/ims_gif/ARCHIVE/AK/2012/ims2012242_alaska.gif

    As for pixel counts, Here is what I get comparing the above image with the Sept 22, 2007 image

    http://www.natice.noaa.gov/pub/ims/ims_gif/ARCHIVE/AK/2007/ims2007265_alaska.gif

    First you have to mask out the yellow box in the legend. Then using Photoshop to get an exact count of the Yellow pixels (RGB=255,255,0) you get:

    ims2012242_alaska.gif = 20,172 pixels
    ims2007265_alaska.gif = 19,296 pixels

    difference = +4.54%

    PS to get the exact pixel count in Photoshop: 1) crop or mask the yellow ice legend box 2) use Select>Color Range with Fuzziness=0 to select the Yellow Pixels, 3) use Window>Histogram and select Expanded View to show the exact number of pixels selected

    • pjie2 says:

      Pretty sure Steve was looking at the previous day, but I’d be surprised to see that much of a difference between them. Can you check what the figures are like for http://www.natice.noaa.gov/pub/ims/ims_gif/ARCHIVE/AK/2012/ims2012241_alaska.gif ?

      • David Sanger says:

        Sure, no problem.

        ims2012241_alaska.gif = 20,763 pixels (Aug 28, 2012)
        ims2007265_alaska.gif = 19,296 pixels (Sep 22, 2007)

        difference = +7.60%

      • pjie2 says:

        Did it myself with ImageMagick:

        Sept 2007: 19,296 pixels

        Aug 27: 21,939 pixels (+13.7%)
        Aug 28: 20,763 pixels (+7.60%)
        Aug 29: 20,172 pixels (+4.54%)

        So, replicated with an independent piece of software, I think we can conclude Steve’s measurements are wrong. Steve, what’s your methodology?

      • pjie2 says:

        Also, Steve – care to let us know how much you charge professionally for image analysis?

      • Richard T. Fowler says:

        David, why have you not included turquoise and magenta pixels in your census? Isn’t that kind of, how shall I say, “important”? Thank you.

        RTF

      • pjie2 says:

        Richard: The original images only have yellow pixels, see the links David put in the post you replied to. He counted each year independently and divided the numbers. Steve’s done something different by recolouring them and overlaying them before counting – likely this step is where he introduced the error.

        If I had to guess, I’d say Steve is counting the turquoise pixels and then (mistakenly) dividing by the number of yellow pixels. That is, instead of using the Sept. 2007 area as the denominator, he’s using only the areas in common between 2012 and 2007. That’s just my guess though, it’s impossible to tell what he’s done. I tried to pixel-count the jpg he posted, but the conversion to jpg (and lossy compression) has dithered the edges and made all the colours fuzzy instead of pure. I can count them, but essentially you have a situation where almost every pixel’s a subtly different colour.

    • Steven Mosher says:

      That explains why I couldnt match his results either. He’s hiding the decline.

  7. David Sanger says:

    Not at all – the comparison is between the total amount of ice in the August 29 2012 NOAA image compared to the total amount of ice shown in the September 22, 2007 NOAA image. Both images show ice in Yellow. So you add up the Yellow in each image and calculate the difference.

    The NOAA images are GIFs which have precise color values.

    The Image posted above with Turquoise and Magenta ( which is a JPEG and not a GIF) simply shows that the ices is not all in the same place in 2012 as it was in 2007.

  8. pjie2 says:

    No, I’m not

  9. David Sanger says:

    Another minor point of detail Steve is that you have selected the Alaska images which as you can see on the right side of the image above cut off the Eastern side of Greenland and the Fram Strait.

    The entire set of images is here: http://www.natice.noaa.gov/ims/gif_archive.html

    The Northern Hemisphere images have the greatest coverage but cannot be used for pixelcounting since they have white latlong marks. However the Europe/Asia images do have complete coverage albeit at a lower resolution.

    here’s the images

    http://www.natice.noaa.gov/pub/ims/ims_gif/ARCHIVE/EuAsia/2012/ims2012241_asiaeurope.gif
    http://www.natice.noaa.gov/pub/ims/ims_gif/ARCHIVE/EuAsia/2012/ims2012242_asiaeurope.gif
    http://www.natice.noaa.gov/pub/ims/ims_gif/ARCHIVE/EuAsia/2007/ims2007262_asiaeurope.gif

    and the pixelcounts:

    aug 28 6105 pixels +14.7%
    aug 29. 5862 pixels +10.2%
    sep 19 5319 pixels minimum

    not a huge difference, but a bit

    • Ice that isn’t included in that picture is all walking dead anyway.

      I checked my spreadsheet and I copied the number over incorrectly. I actually calculated 15.8% difference, not 18%. I am checking now as to the source of the of the rest of the discrepancy

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