22 thoughts on “JAXA Has Updated: I’ve Already Lost!”

1. I distrust the nice round number 8.95 for Nov1st. It smacks of “we don’t have all the data so we’ll guessitmate”. Nice round numbers appear more often in the JAXA data than statistically reasonable (eg Aug 30th, 2008 July 12th, 2008, Jan 4th, 2008 just to name a few), assuming actual data is being used.

2. Fred–
   Good point. Round numbers do look like estimates. The fact that the reported values are delayed also suggests there is an issue.

   Still, these are the numbers we use for betting!

3. Starting to worry that I’m a little high with my bet. Does JAXA do any NASA-like adjustments of previous data? (asked with a hope that Nov 1-3 will be adjusted up)

4. Fred–
   I don’t think any of us know JAXA’s habits. That makes it a bit of a craps shoot for all of us!

5. Speaking of NASA-like adjustments, Licia this is why NASA GISS Temp data is crap:

   http://icecap.us/index.php/go/joes-blog

6. Bob– We all know GISS seems to change it’s mind about past temperatures with some frequency. But crap is a bit harsh.

   It’s unfortunate, but the world just didn’t make measuring GMST a high priority the moment man invented fire. As it took us a while to invent thermometers, deploy them, and figure out all the mistakes we made doing it, there is uncertainty in the historic record. But, like everyone, I have to use temperature products that exist.

   The alternative is to examine nothing.

7. Fred Nieuwenhuis (Comment#6280) November 4th, 2008 at 10:38 am

   “Starting to worry that I’m a little high with my bet. Does JAXA do any NASA-like adjustments of previous data?”

   Yes they do and the true average won’t be known for approx. 3 days after the seventh. As explained in the graph page.

   “Usually, sea ice extent is defined as an average of several days in order to eliminate calculation errors by data deficiency. However, we adopt the average of two days in this site for the purpose of rapid release.”

8. Yes– I’ll be waiting for the JAXA numbers to be stable before reporting the winner. But, the current numbers are also shown in the graph. Unless the wind picks up and compacts a lot of ice, my bet is clearly out of the brownies.

9. Lucia, a ~20-30% change in the data is sure crap to me.

10. After a hard fought campaign, and valuable debate with my esteemed fellow ice guessers, I have fallen to a week of weak ice generating conditions. I held out hope that a massive expanse of calm, radiational cooling would glass over a huge expanse of the Bering Sea. Alas, we simply couldn’t get over the hump. I blame myself. And the AO taking a huge hit and letting the pent-up cold escape.

    I am known as gracious in defeat and cordial in victory, and my only regret is that I will not be eating brownies and singing the victory song. And taunting all the losers.

    http://www.youtube.com/watch?v=dwnqqj5Q1BU

11. The JAXA/IARC website puts out values twice a day. The “late” value is usually different from the “early” value. I’m not absolutely certain, but I think that I once saw the previous day’s value change. I recommend waiting until the “early” value for the 9th is posted, before declaring the results for the 7th official.

12. Agree with Walter, some of their updates are quite large as well so we wouldn’t want to call it to soon 🙂

    Regards

    Andy

13. Fred Nieuwenhuis (Comment#6276) November 4th, 2008 at 10:03 am
    I distrust the nice round number 8.95 for Nov1st. It smacks of “we don’t have all the data so we’ll guessitmate”. Nice round numbers appear more often in the JAXA data than statistically reasonable (eg Aug 30th, 2008 July 12th, 2008, Jan 4th, 2008 just to name a few), assuming actual data is being used.

    Not if you realize that the data is the sum of a number of pixels, depending on the size of the pixels the occurrence of will be more frequent than you think.

14. Apparently JAXA was not on daylight savings time. The morning update appears to be coming in at 9 AM Eastern time now. Speaking of which:

    11/04/2008 9106719 km2

    Running average 8998906.5 km2

    Since that was a big jump from the previous day, the projected average is up to 9.06 Mm2. I haven’t lost yet, but I probably will.

15. “Nice round numbers appear more often in the JAXA data than statistically reasonable”

    The last three digits only come in increments of either 156 or 157.
    The low order digits are:
    000
    156
    313
    469
    625
    781
    938
    1094
    1250
    1406
    1563
    …
    9844
    10000

    9844 occurs 38 times, once more than 00000.

    Also note JAXA updated 11/04 to a gain of 117,656 km^2

    Even if those higher rates continue, due to the anemic start in Nov., it looks like my 9,226 bet will be at least 100k too high.

    Sigh,

    Now I’ll have to break out my own JOC.

    Arthur

16. adoucette (Comment#6312) November 5th, 2008 at 8:40 am
    “Nice round numbers appear more often in the JAXA data than statistically reasonable”
    The last three digits only come in increments of either 156 or 157.

    Yes because the pixel size used in the algorithm is 12.5×12.5 km therefore the area increment is 156.25 km^2 so on average the ending ‘000’ should occur 1 time in 64.

17. Tonight’s preliminary 11/05 extent is 9222969 km2. That’s over 100,000 km2 more than 11/04 and when the initial value is that large, the final value is even larger. That puts the running average at 9043719, so as I expected, I’m out of the running. The projection increased to about 9.11 Mm2 and the 11/1-7 average could again exceed every previous year since data collection by the Aqua satellite started in 2002.

18. As noted earlier, I am surprised by the speed of SST loss in some areas. With just a couple of days(of the bet) to go, I assume the eventual change in ice extent will depend on the wind and wave conditions in the particular areas now being below 0 and -1 deg. C ,SST (Baffin area and Kara Sea). If wind conditions are relatively calm, you might surpass the 2002 ice area, if windy conditions, we may see some leveling off. Any way, my bet was of course way off. 🙂

    Cassanders
    In Cod we trust

19. DeWitt Payne (Comment#6332) “Tonight’s preliminary 11/05 extent is 9222969 km2. That’s over 100,000 km2 more than 11/04 and when the initial value is that large, the final value is even larger. ”

    As DeWitt predicted, the JAXA 9:00 am EST estimate came in at 9,255,625 km^2. A whopping 148,906 more than the 4th (it was all the way back to the 21st of Oct since this rate of change was exceeded)

    Still, I’d need 50% more than that each day to win, so like DeWitt, (who needs a huge unseasonal melt off to win) I’m probably out of the running as well.

    Now I’m rooting for AndyW’s bet of 9,125,000 to hold up.

    On a slightly different note, does anyone know why there is switch to a positive anomaly on June 1st/2nd for almost every year of the Aqua record?

    This is easily seen in the graphs.

    Arthur

20. The morning update for 11/05 has raised the running average to 9050250.2 km2. The projected average is about 9.14 Mm2, but that’s a huge increase over the previous day. Today’s extent is also higher than any previous year for the same day of the year (310) as opposed to calendar date.

21. Dewitt… Yep! I better make a graph!

22. @adoucette,

    It’s the twice annual melt pond adjustment switch. This year the October switch was smoothed.

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