Arctic Sea Ice : Forum

Cryosphere => Antarctica => Topic started by: Paddy on January 02, 2017, 05:13:43 PM

Title: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: Paddy on January 02, 2017, 05:13:43 PM
Poll for the daily minimum as requested. I went for narrow 250000 square km) bands; any strong preference for future polls between these and 500000 square km bands? Voting ends in the middle of January, changing your vote is possible up to that point, and I'd be very grateful if someone could post a list of recent prior minimums.

EDIT: added in one more band at the top, apologies if your vote was reset.
Title: Re: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: Darvince on January 02, 2017, 08:32:11 PM
For reference:

2016: 2.66
2015: 3.59 (2nd highest)
2014: 3.54
2013: 3.69 (highest on record)
2012: 3.22
2011: 2.32 (2nd lowest)

2006: 2.41

1997: 2.25 (lowest on record)

1993: 2.37 (3rd lowest)

1986: 3.01
1985: 2.58
1984: 2.53
1983: 2.91
1982: 3.01
1981: 2.74
1980: 2.53
1979: 2.87

Based on these, I'm voting for the second lowest option.
Title: Re: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: kiwichick16 on January 02, 2017, 09:15:20 PM
2-2.25
Title: Re: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: Pmt111500 on January 03, 2017, 04:43:55 PM
Meh, counting on the disintegrating ice bergs to be counted as sea ice.
Title: Re: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: Gray-Wolf on January 03, 2017, 05:32:26 PM
Meh, counting on the disintegrating ice bergs to be counted as sea ice.

I imagine 'collapse and spread' of towering slabs of calved ice shelf will really mess with ice min figures over the years to come? These 'iceberg flotillas' could leave some areas looking like a well fragmented maximum ice extent pack? Sadly a cold surface keeps the warm waters low in the column and so add to the woes of grounding lines as the warmed bottom water chip away at them.
Title: Re: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: Paddy on January 05, 2017, 07:49:37 AM
From the polling so far, I feel I should have included another couple of buns at the bottom. It's too late to change now imo, but to those of you who voted for the "<2" bracket, roughly how low would you guess that it's going to go?
Title: Re: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: iamlsd on January 06, 2017, 04:48:49 AM
I voted <2 as I see anything below that as essentially zero sea ice and made up from glacier and shelf ice that has broken away.
Title: Re: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: budmantis on January 06, 2017, 05:23:18 AM
I voted 2 to 2.25 as it appears likely there will be a new record, but with my limited knowledge of the Antarctic, I'm not comfortable voting lower. A minimum of less than 2 million is at least somewhat likely.
Title: Re: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: Paddy on January 12, 2017, 01:05:18 PM
4 days until the poll closes, in case anyone was thinking of revising their estimate.
Title: Re: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: kiwichick16 on January 13, 2017, 06:05:37 AM
changed to less than 2 million sq kms
Title: Re: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: magnamentis on January 13, 2017, 06:42:31 PM
I voted 2 to 2.25 as it appears likely there will be a new record, but with my limited knowledge of the Antarctic, I'm not comfortable voting lower. A minimum of less than 2 million is at least somewhat likely.

i voted <2 but wasn't sure since you have a point. but then look at todays drops and we're getting closer to the possibility of <2 considering any of the previous trajectories.

https://sites.google.com/site/arctischepinguin/home/amsr2/grf

check all area and all extent to see what i mean, perhaps you saw that already :-)
Title: Re: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: budmantis on January 14, 2017, 06:49:12 AM
I voted 2 to 2.25 as it appears likely there will be a new record, but with my limited knowledge of the Antarctic, I'm not comfortable voting lower. A minimum of less than 2 million is at least somewhat likely.

i voted <2 but wasn't sure since you have a point. but then look at todays drops and we're getting closer to the possibility of <2 considering any of the previous trajectories.

https://sites.google.com/site/arctischepinguin/home/amsr2/grf

check all area and all extent to see what i mean, perhaps you saw that already :-)

I think there's a better than even chance it will fall below the 2 million threshold and looking over the poll results thus far, it seems most voters feel that way. I tend to be conservative when it comes to making prognostications unless I have a lot of background in observing previous results. When it comes to the Arctic, I do, but not the Antarctic. I'll stay with my original vote, even though I'm likely to be wrong. OTOH I might turn out to be right, and my head will swell to an incredible size, at least temporarily! LOL
Title: Re: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: Darvince on January 14, 2017, 08:45:44 AM
Well all 0 people who voted for the first bin are already wrong! :P It's at 3.95 and rapidly dropping still.
Title: Re: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: magnamentis on January 14, 2017, 11:54:13 AM
I voted 2 to 2.25 as it appears likely there will be a new record, but with my limited knowledge of the Antarctic, I'm not comfortable voting lower. A minimum of less than 2 million is at least somewhat likely.

i voted <2 but wasn't sure since you have a point. but then look at todays drops and we're getting closer to the possibility of <2 considering any of the previous trajectories.

https://sites.google.com/site/arctischepinguin/home/amsr2/grf

check all area and all extent to see what i mean, perhaps you saw that already :-)

I think there's a better than even chance it will fall below the 2 million threshold and looking over the poll results thus far, it seems most voters feel that way. I tend to be conservative when it comes to making prognostications unless I have a lot of background in observing previous results. When it comes to the Arctic, I do, but not the Antarctic. I'll stay with my original vote, even though I'm likely to be wrong. OTOH I might turn out to be right, and my head will swell to an incredible size, at least temporarily! LOL

as i see the majority voted 2-2.25 while i agree with your above statement that there is more than a good chance to see something around 2 or <2M.

i still vote for overlapping values for polls. in this case, if available i would have voted 1.9-2.1M but had to choose and went for <2M
Title: Re: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: Paddy on January 14, 2017, 01:35:33 PM
I'm going for 2 to 2.25; a new record, but not a dramatically different one. A good chunk of the ice that's left is solid stuff, and we're getting near to the end of the melting season now.
Title: Re: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: frankendoodle on January 15, 2017, 04:57:48 PM
If we use 1997 as a template by date we see an average of ~55K km2 per day drop in SIE and a minimum date of 2/19. Those are JAXA numbers.
So if we use this drop rate to fill in the next 36 days of melt we would arrive at minimum of ~1.8M km2.

My post yesterday in Antarctic SIE was based on equivalent area as a starting point and not the date, thus that estimate is higher.
Title: Re: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: Paddy on January 16, 2017, 01:42:52 AM
Voting closes in 17 hours. Last chance to change / post your votes while you can.
Title: Re: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: magnamentis on January 16, 2017, 11:01:28 AM
Voting closes in 17 hours. Last chance to change / post your votes while you can.

will stick to <2M chances are increasing and next time we do it overlapping like 1.9-2.1M because that's where we shall end up and whether it will be 1.999 or 2.001 is prone to measurement inaccuracy and luck/bad luck :-) LOL

thanks for having made this interesting place for nice exchange of thoughts.
Title: Re: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: Lord M Vader on January 16, 2017, 05:55:22 PM
Damn!!! Should have posted, but was apparently 40 min too late.. My vote would have been 2-2,25 Mn km2 if I had managed to post my vote before the voting was closed.
Title: Re: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: frankendoodle on January 18, 2017, 07:51:41 AM
At this point I am guessing that the minimum will be between 1.8M and 1.7M km2.
Title: Re: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: Paddy on March 08, 2017, 01:07:25 PM
It's looking quite a lot like we have a winner (2 to 2.25), though I'd like to wait another week or so before calling it, just in case.
Title: Re: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: crandles on March 08, 2017, 03:33:26 PM
It's looking quite a lot like we have a winner (2 to 2.25), though I'd like to wait another week or so before calling it, just in case.

Largest falls after now in March that I could find 2004 26.5k from 26th to 27th 2006 3.5k for 13th to 14th and 1k for 2011 9th to 10th.

I guess I could believe four time the size of the previous largest fall after this date to create a later minimum could occur even if that seems very unlikely after 6 consecutive rises. Also there are 38 years with 12 or 24 data days where a fall could have occurred and I only found 3 falls.

10 times larger to get into a lower bin seems stretching it a bit.

I called it after 4 consecutive rises even though it was only 40k above the minimum on the other thread. If you want to be really safe, another day or two seems likely to be plenty. A week seems overly cautious.
Title: Re: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: Paddy on March 08, 2017, 06:15:45 PM
I'm away over the weekend.  Let's compromise and call it on Monday :-)
Title: Re: Poll for 2017 IJIS daily minimum Antarctic sea ice extent
Post by: Paddy on March 13, 2017, 04:16:37 PM
Yeah, even with only the NSIDC figures to go on in the other thread recently, I think we can call this for the 2 to 2.25 bin. Good guesswork, everyone!