I fiddled with my spreadsheet and added the most recent 7 day lagging average. As you can see, so far no one has lost. With luck, I won’t have lost before Nov 1 arrives tomorrow!
Because the squiggly line plots are difficult to read, I computed the 2002-2008 average and then found the NH sea ice anomaly for 2008 by subtracting the average. As you can see, defined this way, the anomaly flipped from negative to positive:
Of course, we all knew the ice was freezing fast. Also, the anomaly using 30 year data would differ.
As usual, here’s a live version of the JAXA figure:
Future bets: I like to close bets before data specifically involved in determining the winner are in. So, that means no betting on the Nov-Dec-Jan because there is no way for anyone to place bets before Nov 1. But, we could bet on the December average. In which case, I’d close bets on …. hmmm… Nov 25? To minimize the “rebetting” syndrome, I’d only permit people to place bets during the seven day period before bets close, and tell people they can’t change their bets (unless they make obvious blunders, like missing “millions” or something like that. ) 🙂
The rate of extent growth tends to fall off about now, at least in this century and I think there were a lot of optimistic bets. Today’s extent is 8.817. My projection based the average over the 2003-2007 time frame has it is going to be about 8.955. Not a bet just a projection(or is that a prediction?).
lucia,
Are you correcting for the leap days in 2004 and 2008? It makes a difference.
DeWitt–
I just calculate the average for the stated calendar days.
Is there a correct way to adjust for leap days? Jan1 doesn’t have any particular physical significance, and measurements are only given for calendar days. So…. how would we adjust in a meaningful way?
lucia,
I think that neglecting the leap year correction made my bet too low by about 100,000 km2. That’s how much the 2002 to 2006 11/1 to 11/7 average changed by using 11/2 to 11/8 average for every year except 2004. I guess I could fine tune it further by interpolating between the values for 11/1 to 11/7 and 11/2 to 11/8 . That would mean add 1/4 of the difference to the 11/1 to 11/7 average for 2005, 1/2 for 2002 and 2006 and 3/4 for 2003 and 2007. JAXA is late updating tonight so I’ll try that and see how much difference it makes. My guess is that it will about split the difference.
It lowered the projected extent by 25,000 km2 to about 9.08 Mm2. It also put 2005 seriously in play at 9.136 Mm2 so 2008 could reach a new record for the 2002 to 2008 period. Not that that means all that much compared to the longer term average. Here’s the corrected averages using linear interpolated values for any missing data.
2002 9114743
2003 9046644
2004 9101072
2005 9136194
2006 8903047
2007 8618594
The horses are in the starting gate. 2008 seems to be tracking 2005 at the moment so here are the starting figures, correcting 2005 by adding 1/4 of the difference between 10/31 and 11/1/2005:
date 2005 2008 average
10/31 8.886 8.892 NA
I haven’t lost yet. All I need is a gain of about 401,913 sq km per day for the next 7 days.
OK… I’ve lost…
After crunching some numbers I think:-
Philip Mulholland(#5960) October 24th, 4:13 am 9,258,000
Bob B (#5751) October 9th, 4:18 pm 9,300,000
Are the best bets.
Sorry MIke B, once we were in the running and then the witt of de beat us, and now SteveM and EarleW beat deWitt, but Mark R says “It is not over until it is over.”
Lucia, perhaps in the last and only last week, month, whatever, the losers?? could vote and select the ones they think will win. Of course if they do they give up their original bet. As per MartinGAtkins bet on Phillip and Bob.
John F. Pittman (Comment#6191) November 1st, 2008 at 6:58 pm
“Lucia, perhaps in the last and only last week, month, whatever, the losers?? could vote and select the ones they think will win. Of course if they do they give up their original bet. As per MartinGAtkins bet on Phillip and Bob.”
G’Day John.
I haven’t bet on Phillip or Bob or abandoned my original bet. I just think I’m out of the running. I was only making commentary on the race progression.
The recovery to near-2005 levels is actually a pretty fierce year-over-year growth. Estimating from De Witt’s numbers, the largest prior increase was 55k from 2003 to 2004.
We’re looking at something closer to a 500k increase over 2007.
I really wouldn’t be shocked if it was the largest increase in the entire record instead of just 2002-current. (Mostly because 2007 was the lowest ever, and the ice appears essentially entirely dominated by topography during this period.) But still interesting.
MartinGAtkins (Comment#6189) November 1st, 2008 at 6:29 pm
“After crunching some numbers I think:-
Philip Mulholland(#5960) October 24th, 4:13 am 9,258,000
Bob B (#5751) October 9th, 4:18 pm 9,300,000
Are the best bets.”
Ooops! I made a mistake.
I think Philip Mulholland and Bob B are closest to the _total_ extent on Nov 7, but we are betting on the average over the seven days. My projection is 9,153,715. What do you know…after tinkering with my model I’m still in the running. 😉
As of 10:26 AM EST, JAXA hasn’t posted a number for 11/1. I checked the csv file as well as occasionally they post the number to the archive file before they update the page. If we get a -9999 for 11/1, some of the higher estimates start looking a lot better.
6:35 PM EST, Still no JAXA update for 11/1.
If you back up one level on the JAXA site, there is an image of the Arctic dated 11/1/2008, so it’s not as if the satellite wasn’t working. Is 11/1 some sort of national holiday in Japan? I guess we’ll see when(if) data is posted for 11/2 whether the data for 11/1 will be in the CSV archive file.
I think JAXA know about this competion and are having a bit of fun with us. I think a 9.250-9.30 is going to take the biscuit. literally.
Regards
Andy
Spring in the air or which way the wind blows
10,31,2008,8892344
11,01,2008,8950000
11,02,2008,8924688
Current projected average based on data through 11/3/2008:
2002 to 2006 only 9.037 Mm2
2002 to 2007 9.023 Mm2
That would be higher than just 2006 and 2007.
The projection is dropping though. It was 9.058 and 9.051 Mm2 based on data through 11/2/2008.