Cryosphere Today 2014 Arctic SIA daily minimum: July poll

[Neven]

ATTENTION: There are two polls on the ASIF. One is for NSIDC sea ice extent monthly/September average minimum, the other is for Cryosphere Today sea ice area daily minimum. Make sure you are aware of the difference before voting. You can discuss various extent/area data sets in this dedicated thread.

-----

This CT SIA poll will run for 10 days (until July 11th). Until then you can change your vote. There will be a new poll next month.

Here's how things are currently looking based on data up to June 29th:



These are the daily minimums for the last 7 years (in millions km2):

    2005: 4.092
    2006: 4.030
    2007: 2.919
    2008: 3.004
    2009: 3.425
    2010: 3.072
    2011: 2.905
    2012: 2.234
    2013: 3.554

The average for the June poll was 2.75 million km2.

You can use the comment thread below to motivate your choice, but discuss various SIE/SIA data sets in this dedicated thread.

[Neven]

Although I decided to vote one bin lower on the NSIDC poll, SIA has been a lot less responsive to the recent sunny weather. There seems to be little melt ponding so far, but more importantly, very little divergence of the ice pack as well. So I'm sticking with last month's vote: Between 3.0 and 3.25 million km2.

I might go lower if this weather keeps up (votes can be changed until July 11th), and I probably will.

[TerryM]

2.75-3.00


Lower if we get a little cyclonic action for Ekman pumping.
Terry

[johnm33]

July poll  average?   June poll surely.  [x2]

[jdallen]

3.25 to 3.5

My full range, 95%, 2.45 - 3.75

[jdallen]

2.75-3.00


Lower if we get a little cyclonic action for Ekman pumping.
Terry

If we get a cyclone in August, all bets are off.

[Siffy]

Although I decided to vote one bin lower on the NSIDC poll, SIA has been a lot less responsive to the recent sunny weather. There seems to be little melt ponding so far, but more importantly, very little divergence of the ice pack as well. So I'm sticking with last month's vote: Between 3.0 and 3.25 million km2.

I might go lower if this weather keeps up (votes can be changed until July 11th), and I probably will.

I have a feeling that cloud cover has been hiding melt ponding from being visible on concentration graphs.

there seems to be fair amount of melt ponding visible in this webcam for instance.

[johnm33]

I'm fairly convinced, [balance of probabilties] that the ice now is like a layer cake and that we have snow and ice layers, also I'm not confident that Piomas volume means what it used to. Snow can be 15-40% the mass of ice, it's easy to imagine, given last years conditions, that each snowfall was followed by freezing fog or 'ice storms' which in turn was followed by snow. Any melt ponds appearing on such fragile formations is unlikely, either finding a weak  spot it melts through, or the icing layer  has tilted and the  melt flows off. So any prediction based on melt ponds my wag would discount by 50% . I no longer think that anything over 4.5 is possible and if my view on the 'mass' of the ice, as per Piomas, is correct a max of 3.2 and a min of 1+ : so a conservative 2.1

[Neven]

July poll  average?   June poll surely.  [x2]

While I was writing, I was thinking to myself: Where am I going to screw up?

Thanks for finding it, johnm33. Fixed now.

[Tor Bejnar]

As last month, I vote for a functional tie with 2012 because I'm pessimistic about the quality of most of the ice. Every effort of mine to calculate 2013 minimum ice area/extent fell extremely flat, so I am old fashioned guessing based on my (political) worldview for all to see!   I don't have time to learn much (although I read/skim most of the Arctic Ice threads) or experiment, but I'm sure glad for those of you that do.

[Michael Hauber]

2.75-3.00

The weather seems a bit coolish, and lack of surface melt.  But how we could fail to beat a year like 2008 with 6 years of warming and the large areas of open water in Chukchi/Beaufort/Laptev?

[Yuha]

I have raised my prediction by one tick from the June poll to 3.0-3.25.

The main reasons for the uptick are the continued lowish DMI 80N temperatures and the lack of export through Fram Strait. I have looked at other and more detailed evidence too but haven't seen any other strong signals either way.

[cats]

I am staying with 2.75-3.00, same as last month. 

[Neven]

I might go lower if this weather keeps up (votes can be changed until July 11th), and I probably will.

Now I'm thinking about going one bin up after the latest PIOMAS update.

[Tor Bejnar]

I've just removed my (~2012 value) vote, and now I abstain.

The Healy scientists, apparently, claim a late dusting of snow seriously increased the albedo where they hoped to study algal blooms.  (See links in Healy thread).  I wonder if a late snow across the CAB put a serious damper on heat retention, and therefore melt.  Or was it all that fog.  Or was it the minimal wind?

[icefisher]

Lack of a prominent dipole centered on Greenland is forcing the Sun to melt ice all by itself.  Area falls fastest when both Sun and wind combine forces to destroy ice.  I am going with 3.39 area at minimum.

[ChrisReynolds]

Using my 1980 to 1999 baseline, I've calculated CT Area anomalies for a 7 day average centred on 1 July, and a 7 day average centred on 15 September. That gives a measure of how anomalies can drop over the late summer, from 1979 to 2013 the maximum drop is about 0.65, 2008, 2009 and 2012 have drops similar to that  - so large drops are not something unique to extreme years. Anyway, in 2014 during the July centred period anomalies have been -1.32, lets say they drop by the maximum seen in the post 2007 period. That lets anomalies drop to -1.97 by around 15 September, approx time of the minimum. For my baseline period the average seasonal cycle around 15 September (7day avg centred on that date) is 5.025M km^2 CT Area.

5.025 - 1.97 = 3.06M km^2 approx - the lowest 2014 can get to this year without more massive drops in anomaly than have been seen since 1979.

So 3.0M km^2 is the lowest I think we might see, but I estimate it will be higher than that.

If there is no anomaly loss this year - anomalies stay the same all summer - it's a re-run of 2013. I don't expect that.

So I'm going back to my 3.0 to 3.3 originally calculated in late June based on 20 June CT Area. Voted 3.0 to 3.25, but I reserve and extra 0.1 on that, so call my prediction 3.0 to 3.4M km^2.