Now that the melting season is underway and we have had the opportunity to study the prelude, this is a good moment to start guessing the minimum. But there are different kinds of minimum: area, extent, daily minimum, average September minimum. Of course, the difference between extent and area is well-known and area tends to be lower than extent. There's also a difference between the day in September with the lowest extent/area, and an average of all September days.
Personally I'm a big fan of minimum daily extent/area polls, because that makes it more exciting around the time of the minimum (not having to wait until October for the final result to come in). On the other hand, the monthly SEARCH Sea Ice Outlook reports, where science pros and knowledgeable amateurs submit their guesses, garner more interest every year. And these are for the NSIDC September (monthly average) minimum extent. Okay, so let's do two polls then. But which datasets?
Last year the polls were focused on IJIS minimum daily sea ice extent, but because of the switch to WindSat it's not sure yet how 'trustworthy' or consistent it is. That means there's only one option left and that's the Cryosphere Today sea ice area numbers (to be found here).
These are the daily minimums in the 2005-2011 period:
- 2005: 4.09 million square km
- 2006: 4.03 million square km
- 2007: 2.92 million square km
- 2008: 3.00 million square km
- 2009: 3.42 million square km
- 2010: 3.07 million square km
- 2011: 2.90 million square km
The other poll will then obviously be focused on the NSIDC September minimum sea ice extent numbers (to be found here), so that we can compare the blog community's estimate with the estimates submitted to SEARCH.
These are the September monthly average minimums in the 2005-2011 period:
- 2005: 5.57 million square km
- 2006: 5.92 million square km
- 2007: 4.30 million square km
- 2008: 4.73 million square km
- 2009: 5.39 million square km
- 2010: 4.93 million square km
- 2011: 4.61 million square km
Both polls are in the right hand bar and will be replaced every month by new ones. These first polls run until June 30th.
Edit: I've made a mistake in the question of the NSIDC poll. It says "The NSIDC minimum monthly/September sea ice area for 2012 will be", but of course 'area' should be 'extent'. Sorry for the confusion. I've changed the poll, but it could take some time to show up.