On Wednesday, 12 October 2016 12:41:53 UTC+1, N_Cook wrote:
Has there ever been an observable double minima in the ice area , if
there is sustained elevasted temps and sustained storminess over the Arctic?
All I can find is decadal average plots, for earlier records.
Presumably any second minimum would not be so deep as the initial one,
but what effect would any such double minimum have on ice recovery?

I was monitoring the ice extent every day during September of the years 2003 to 2009. All those years had at least a double minimums. The day of the first minimum in 2002 was 9th September, and it advanced each year by about 1 day until 2008 when the first minimum was the 9th again and the second minimum was 1 day later than the first minimum in 2007, ie on 17/8/2008 and 16/9/2007 repectively. The second minimums also advanced by roughly a day each year, and in 2008 there was a third minimum one day laterthan the 2nd min in 2007.

In 2009 the first min was on 13/9/2009 and the second on 16/09/2009 completely upsetting the pattern :-( I didn't monitor it after that.

This year seems to be an exception with only one minimum, but that may be because they are averaging over five days instead of recording each day.

If you want I can email the values displayed in an Excel spread sheet.

OTOH, here are the values if you want to play with them yourself

2009 2008 2007 2006 2005 2004 2003 2002
08/09/2009 5,330,469 4,715,469 4,413,438 5,935,781 5,642,656 5,839,219 6,103,750 5,649,688
09/09/2009 5,315,938 4,707,813 4,399,531 5,936,094 5,628,281 5,835,313 6,086,406 5,646,875
10/09/2009 5,295,313 4,729,688 4,367,188 5,926,094 5,599,844 5,825,000 6,060,469 5,655,156
11/09/2009 5,278,594 4,751,563 4,343,438 5,896,719 5,581,875 5,784,688 6,041,250 5,674,063
12/09/2009 5,259,375 4,745,156 4,327,969 5,864,219 5,545,000 5,806,719 6,105,625 n/a
13/09/2009 5,249,844 4,742,344 4,323,750 5,814,063 5,506,563 5,854,375 6,180,313 n/a
14/09/2009 5,276,563 4,747,188 4,291,250 5,781,719 5,522,344 5,901,094 6,146,563 n/a
15/09/2009 5,301,094 4,731,875 4,267,813 5,794,063 5,492,500 5,912,188 6,049,844 n/a
16/09/2009 5,291,094 4,726,250 4,267,656 5,806,094 5,447,656 5,882,813 6,041,875 n/a
17/09/2009 5,326,094 4,718,594 4,268,750 5,828,281 5,422,344 5,821,250 6,033,281 n/a
18/09/2009 5,348,438 4,736,406 4,281,406 5,874,063 5,385,156 5,809,688 6,032,031 n/a
19/09/2009 5,358,594 4,745,000 4,296,250 5,892,500 5,368,438 5,808,750 6,088,906 n/a
20/09/2009 5,383,594 4,752,500 4,310,313 5,846,875 5,345,156 5,818,906 6,122,656 n/a
21/09/2009 5,401,875 4,773,750 4,284,531 5,847,656 5,315,625 5,866,719 6,085,469 n/a
22/09/2009 5,432,813 4,809,219 4,276,719 5,851,406 5,315,156 5,925,625 6,047,031 5,985,781
23/09/2009 5,417,031 4,873,125 4,267,344 5,883,281 5,335,156 5,994,688 6,080,469 6,001,563
24/09/2009 5,408,281 4,878,750 4,254,531 5,972,188 5,377,969 6,107,188 6,101,719 6,047,969
25/09/2009 5,439,688 4,873,750 4,265,000 6,036,719 5,407,656 6,169,531 6,137,031 6,075,000
26/09/2009 5,480,781 4,945,313 4,297,813 6,039,844 5,460,781 6,204,375 6,152,813 6,148,281
27/09/2009 5,516,406 5,003,906 4,372,188 6,016,094 5,524,375 6,257,031 6,156,875 6,244,063


HTH, Alastair.