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Jim Hunt

Thanks Neven - An unusual and most interesting setup for July and August, when bottom melt really sets in across the Arctic. More from me on that in a bit, but first of all here's the view this morning from the camera that used to be keeping a close eye on IMB Buoy 2015B:

Click the image for a larger version.

The buoy itself is nowhere to be seen, but currently reports its position as 76.45 N, 161.90 W, which I reckon counts as the Central Arctic.

It was even suggested on the forum that smoke from Alaskan wildfires is visible in the distance, and you can certainly see some ripples on the surface of all that open water. More to come from me on that topic too!

Neven

Lovely view, barbecue smells, some waves...

Thanks, Jim. :-)

Paddy

So an atypical year, with lots of ice melting in situ but very little export.

@Jim Hunt,
Those wildfires may not be Alaskan. Millions of hectares have been ablaze in Canada too.

http://www.ciffc.ca/index.php?option=com_content&task=view&id=25&Itemid=27

Jim Hunt

Click through to the forum Neven.

Those "waves" are much bigger now, and the barbecue was a washout!

Chris Reynolds

This high over the Arctic Ocean and Greenland, with what looks like low tendency over the Siberian coast looks more like the typical summer set up of 2007 to 2012. In line with that the UK forecast is for low pressure dominance.

If this develops, it would have the potential to put us in 2007/2011 territory. Maybe lower? Maybe but just to get back down to 2007 would be enough after the last two years.

Kevin McKinney

Fascinating. Been wondering when/if the very warm global temps we've been seeing over the last year or more would translate into specifically Arctic effects.

The twists and turns of Arctic melt seasons may be kind of slo mo, but they don't stop coming.

Chris Reynolds

Kevin,

GISTEMP had 2014 as the warmest year on record. Yet it was cold even compared to 1970 to 2000 in the Arctic.
http://4.bp.blogspot.com/-4CI_FUFZ2r0/VZa-BBU96dI/AAAAAAAACOg/QeT_MBYbz2w/s400/Temp%2BN%2Bof%2B80%2Bsfc.png

Chase Stoudt

I just talked to someone who came back from Kotzebue yesterday. They did some CTD casts in the sound and the thermocline temp was 17C! This is only 2.5 weeks after the ice left!

Andy Lee Robinson

Piomas for June has just been published.

           May      Jun      Jul
2007  23.078  19.110  12.038
2008  24.102  20.498  14.061
2009  23.851  19.649  12.733
2010  22.181  17.044  10.153
2011  21.108  16.403  9.457
2012  21.677  15.896  9.177
2013  21.839  17.447  10.446
2014  21.878  17.600  11.880
2015  22.991  18.448

June average now 18,448 km³ and catching up with the trend.

http://haveland.com/share/arctic-death-spiral.jpg

Neven

I'll have a PIOMAS update up tomorrow evening or the day after.

Colorado Bob

Yesterday's Aqua/MODIS pass over Alaska -
Note wind direction

Fires and smoke in northern Alaska

http://rapidfire.sci.gsfc.nasa.gov/cgi-bin/imagery/single.cgi?image=Alaska.A2015187.2300.2km.jpgToday's passes :

North of the Bering Strait

http://rapidfire.sci.gsfc.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl1_143.A2015188082500-2015188083000.2km.jpg

North of the Arctic Wild Life Refuge –

http://rapidfire.sci.gsfc.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl2_143.A2015188153500-2015188154000.2km.jpg


Colorado Bob

I wonder what Jason Box is doing tonight ?

Colorado Bob

From Climate Central:

Two Maps Show Greenland’s Sudden Melt Season Onset

It appears that Greenland’s melt season is making up for lost time.

After a cool spring kept Greenland’s massive ice sheet mostly solid, a (comparatively) warm late June and early July have turned half the ice sheet’s surface into liquid, well outside the range of normal for this time of year.

http://www.climatecentral.org/news/maps-greenlands-melt-season-19196

Paddy

@Colorado Bob,

Indeed. With 1.5 million hectares burnt in the USA (mainly Alaska) so far this year and 2.4 million hectares burnt in Canada (principally Saskatchewan but generally all over the north and west of the country), and no end in sight on either side of the border, this looks like a big year for wildfires.

Paddy

Link to numbers here: http://www.ciffc.ca/rss/report_en

Pete Williamson

Neven if what you say is true and in general continues thru the melt season it might make for an interesting test year.

I've wondered to what extent dynamical and thermodynamical processes have contributed to ice loss post-2007 (maybe even post-2000). Can heat minus export produce the extreme lows? Is lack of export alone enough to allow for another 'recovery' year? Its not that I dont think a warmer world melts Arctic ice, just that the heat in conjunction with 15years of weather patterns have given us a (substantial?) overshoot on ice loss that warming alone would have done.

There was some recent research that suggested that weather patterns in the Arctic had been unusual since around 2000 (I think compared with 100+ years previous) and that 2013 (and 2014?) represented a reversal of that persistent pattern. And also that those weather patterns (teleconnections?) have had a sizable impact on ice loss.

Colin Maycock

Seems like 2015 has decided to play catch-up. Jaxa has report two centaury breaks over the last two days (112 and 163).

Colin Maycock

Sorry – I meant to type “century” (as in one hundred) rather than "centaury" - the plant

Neven

Rutgers reports that this year's NH snow cover in June is second lowest on record:

Bill Fothergill

"centaury"

Colin, thanks for my continuing education: I had no idea that was the name of a plant.

By any chance, would its aroma be known as "scentaury"? (groan)

Jim Hunt

Since Pete has touched on thermodynamics, here's a closer look at what's been happening to the ice underneath ice mass balance buoy 2014F, currently located north of the Beaufort Sea at 75.63 N, 145.75 W. Here's a graph showing the position of the top and bottom of the ice floe, measured using acoustic sounders:

and here's the thermistor profiles showing the temperature within the ice:


Click the images for a closer look.

In approximate terms, half of the ice floe has melted away over the last month.

navegante

And the other half will within 2 weeks.

navegante

Beaufort ice melting apparently stalled during last half of June due to divergent drift of MYI toward the warm coast.
I wonder if those MYI blocks seemingly resistant to melting will just go poof within the next two weeks too.
Bottom melt is unstoppable given the SST's observed on the Beaufort sea.

Bill Fothergill

On the June SIPN thread, Robert S reiterated what many people have been saying for a long time: taken by itself, extent is a pretty ropey metric when it comes to really getting a handle of the loss of sea ice.

Let's face it, extent was basically a warning to navigators, roughly akin to "here be dragons".

There has also been considerable speculation regarding the way area and extent numbers seem to have been behaving of late.

It can be quite educational to look at the way extent and area have varied since the days of the Scanning Multichannel Microwave Radiometer (SMMR). The first SMMR device was on the Nimbus 7 payload, and came into service at the end of October 1978. Along with its various successor devices, such as SSM/I and AMSR, this has provided the basis for most sea ice datasets. (Bremen is the obvious exception, as they also splice in the earlier ESMR data stretching back to 1972.)

Anyway, looking at the entire NSIDC dataset (for both extent and area) from 1979-2014, we can extract the following long-term averages...

Mean difference between March average and September average...
Extent 9.1 million sq kms versus Area 8.86 million sq kms

However, for the most recent decade, 2005-2014 these become...
Extent 9.93 million sq kms versus Area 9.59 million sq kms

The Max <> Min range for extent and area therefore grew by, respectively, 9% and 8%. This is, of course, simply explained by the fact that the autumnal Minimum is dropping faster than the spring Maximum. (A mind-numbingly obvious corollary to this is that the annual winter regrowth between September to March is actually getting bigger. To the arithmetically challenged, this is often used as "evidence" that Arctic sea ice is recovering.)

Irrespective of whether one uses 1979-2014, or 2005-2014, the mean March-September loss in extent exceeded the corresponding loss in area by just 3%.

However, if one focusses on the losses between the June averages and the July averages for the same periods, things could hardly be more different. For the 1979-2014 period, these were...
Extent 2.28 million sq kms versus Area 2.80 million sq kms

In other words, the loss in area actually averages out as 28% HIGHER than the corresponding loss in extent over the June - July period.

Things change again when we look at the last 10 years. Over the 2005-2014 period, these became...
Extent 2.79 million sq kms versus Area 2.90 million sq kms

Although the June - July area loss still exceeds the corresponding extent loss, it now only does so by around 6%, as opposed to the "normal" 28% when the entire dataset is examined.

The reason? The huge extent losses that we have seen during the last 10 years.

The June - July area loss for 2005-2014 exceeded the 1979-2014 value by 5% - a figure roughly comparable to the 8% increase when the corresponding Max - Min (Mar - Sept) figures are considered. However, when we look at June - July extent, rather than area, the 2005-2014 figures exceed the 1979-2014 numbers by a staggering 22%.

I know this is not exactly comparing like with like, but the drop in the NSIDC daily extent figures from 6th June - 6th July 2015 is currently languishing at a mere 1.7 million sq kms. I don't know how to access NSIDC daily area numbers, but the latest 30 day drop in CT area comes to 2.78 million sq kms. (Latest CT date stamp 2015.5123, i.e. Day 187. This therefore includes at least part of the uptick "predicted" by Wipneus in the OP.)

The glaring mismatch between these 30-day figures does tend to suggest that there could just be interesting times ahead.

cheers billf

Pjie2

Heya - is that your own graph for 2014F? The one on the web has no bottom pinger, and moreover the record stops in mid March.

http://imb.erdc.dren.mil/irid_data/2014F_Plot.png

Jim Hunt

Pjie - No, it's fresh from the ERDC web site, but hidden from view there. The pingers started reporting again after a brief hiatus, but the web site didn't get updated to reflect that fact.

Don't forget to check the thermistor profiles too. More on that shortly, but see the ASIF for some hints!

Jim Hunt

The IMB processing pipeline has burst back into life after a brief hiatus, and reveals that the floe (or floe + melt pond?) under 2014F is currently 89 cm thick.

navegante

It is wrong to assume that open ocean with high SST will induce bottom melting directly

OTOH, it is correct to assume that open ocean with high SSTs will indirectly induce bottom melt by: air absorbing heat by evaporation, South wind transporting that air mass to the top of the ice, and air transferring that heat to the top of the ice.

(right ...?) :-)

Bill Fothergill

" ... and air transferring that heat to the top of the ice."

Wouldn't that just be top melting then? ;-)

(Of course, it could just be me being my normal thick self, and misinterpreting what you said.)

navegante

Yes but upon top melting, the surface is sweet water, temp goes up to 0C and a heat flux is established by which the ice starts to acquire a temperature above -1.5C, required for bottom melting. Because there is stratification of salt, the ice being "sweeter' at the top and saltier at the bottom.

Sort of what Jim Hunt plot above shows for most recent date.

It looks to me that it is difficult for the open ocean warm water to reach the bottom except for a limited distance within the ice floe. I think I understood this from a commenter over the forum

Excusr my English

navegante

I scratch my previous comment. Whatever is what I described, it is "melting from the top", aka top melting.

Still I am not sure whether warm waters such as in Beaufort sea will generate more top melting over the ice floes (by the wind heat transport mechanism I described) or more bottom melting (by direct intrusion or mixing or warm water under the ice)

Jim Hunt

Bottom melt usually starts to overtake surface melt in July. This year 2014F (and other buoys too) reveal an earlier onset than "normal". Compare this year with last for example:

http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/summer-2014-imbs/

Robert S

A really interesting "tour de data", Bill. I have to find time to dig in more myself.

Bill Fothergill

Cheers Robert.

Your choice of words was seriously spooky, as I am heading off across the Channel tomorrow morning to watch a few stages of le Tour de France.

A bientot

Kate

There are paw prints at the north pole. I know the image will change but they were there when I last looked :)

http://psc.apl.washington.edu/northpole/NPEO2015/2015cam2_1.jpg

Jim Hunt

Thanks Kate. Here's the archived version:

ftp://northpoleftp.apl.washington.edu/NPEO_2015_Accumulating_Webcam_Images/NPEO_2015_WebCam%232/npeo_camera2_20150709175613.jpg

Of course the camera is not actually at the North Pole. Current cam position is 86.65 N, 3.86 W, where the air temperature is currently 2.24 C.

Once upon a time a buoycam actually snapped a bear!

http://GreatWhiteCon.info/resources/arctic-sea-ice-images/summer-2013-images/#OBuoy7

Neven

Are those paw prints, or foot prints that were snowed over and are now revealed again as the snow melts?

Jim Hunt

Neven - If you go the archive and look at the previous picture those prints were nowhere to be seen.

Given that they're recent do you suppose they are animal, human or alien?

Neven

They must be alien, Jim, because an animal would just walk around and not only in paths between the various devices. :-P

Lennartvdl

Can you tell what kind of alien?

Neven

An alien wearing human shoes.

Lennartvdl

o-oh...

Kate

@Jim, it sounds better when you say 'north pole' hehehe

and it's not an alien, it's SANTA!

Jenny E. Ross

Sorry to disappoint the alien advocates and Santa devotees, but my guess is definitely polar bear. At this distance, and with low resolution, polar bear footprints would look similar to a human's (or an alien wearing human shoes, or Santa for that matter), especially in slush that doesn't retain details. And a polar bear would not just wander around aimlessly. It would walk in an efficient path to the objects that looked and smelled most interesting. Like a human, it would carefully walk between objects. As soon as it determined there was nothing of importance (most importantly, something to eat), it would continue on its way.

Neven

I just remembered an instance in the past couple of years where we also thought it were paw prints and then it turned out that they were human footprints revealed by the melting snow. This current image looked similar to me like that, but it might be ice bear prints.

Edit: Polar bear prints. Dutch word for polar bear is 'ijsbeer'.

Neven

Everyone, there's still a couple of hours left to vote or change your vote on the NSIDC 2015 Arctic SIE September minimum: July poll. Let's make it 100 voters again!

Jim Hunt

I don't think there can be any argument about these prints from earlier in the year:

http://GreatWhiteCon.info/resources/arctic-sea-ice-images/winter-201415-images/#IMB2015A

Click the image for a closer look

NeilT

Well either that or someone was wearing extremely interesting shoes.... ;-)

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