Short to Medium Term Arctic Sea Ice Conditions Discussion

[ktonine]

friv and werther thanks for the update.

Yes, there's definitely room for compaction.  As I wrote earlier regarding the possibility for a new record, a wind shift compacting the ice would have to be in the cards.  If the forecast holds we could see some large extent losses simply due to compaction.

Assuming this happens, I think the next question revolves around the strength of the ice in that region.  Is it solid enough to just wedge together, or will a significant fraction simply fall apart or ridge under mechanical pressure - reducing both extent and area?

Every time I'm ready to believe that 2013 has no chance of surpassing 2012 I look at the low concentrations north of 80 and think, there's no way *that* can exist in a 'cold' year

2013 has driven home a point that is often brought out by paleo-arctic proxies: there can be wide variations from one part of the arctic to another.

[ktonine]

Jim - my guess is that in the low concentration areas north of 80 what is likely happening is a lot of lateral melt and some bottom melt.

Right now the ice is mainly snow covered - the snow albedo would mean that most incoming radiation is being reflected - though due to cloud cover it's probably bouncing up and down until it hits a patch of open water where it can be absorbed. 

Due to all the open water there are countless kilometers of exposed floe perimeter to absorb incoming radiation and be lapped at by ocean water.  The incoming radiation being absorbed by the ocean waters in these low concentration areas should also induce bottom melt.

[Artful Dodger]

Right now the ice is mainly snow covered

Hi ktonine,

Do you have some evidence of that? It is unlikely since winds from PAC2013 would have caused sea water to lap over most floes.

Once snow gets wet, it loses it's crystalline structure permanently, and it's increased albedo.

So unless you can present some evidence like AMSR2 Snow-over-sea-ice data, I will assume you are wrong.

[ktonine]

Look at the low concentration ice floes in Modis - they appear to be snow covered - very white.  Contrast them to what we see in the marginal ice zones around the Beaufort. The north Pole webcams show it still snowing in one location - even though water can be seen in the background. The two north pole webcams aren't in the very low concentration areas, but I think they're probably representative of coloration (albedo) if nothing else.

The edges of floes will be splashed with water - hence the lateral melt, but even the smaller floes visible on Modis are hundreds of meters in diameter. 

With air temps below zero and generally cloudy skies would you expect top melt?  Have you any evidence of top melt in these areas? 

[jdallen]

Jim - my guess is that in the low concentration areas north of 80 what is likely happening is a lot of lateral melt and some bottom melt.

Right now the ice is mainly snow covered - the snow albedo would mean that most incoming radiation is being reflected - though due to cloud cover it's probably bouncing up and down until it hits a patch of open water where it can be absorbed. 

Due to all the open water there are countless kilometers of exposed floe perimeter to absorb incoming radiation and be lapped at by ocean water.  The incoming radiation being absorbed by the ocean waters in these low concentration areas should also induce bottom melt.

Most of the melt in this region is probably, disproportionately on the smaller floes. There is going to be some bottom melt on larger flows - > 100M diameter - but side melt on those will be negligible.

The serious melt above 80 is only just starting to rev up, if past years buoy data is any indication.

[ktonine]

jdallen - why would lateral melt be dependent on floe size? I can't think of any physical reason for lateral melt rates to be different on a 50 meter diameter floe as opposed to a 5 km diameter floe. 

Bottom melt may affect smaller floes more. The exposed surface water will slightly warm and then move under the floe. With large floes this water may lose its warmth before traveling very far under the floe.  Even saying this, I'm not sure the actual volume of ice melted is dependent on floe size.  It's just more apparent on smaller floes - i.e., they shrink and disappear quicker.  But that's a function of beginning volume, not melt volume.

[Bob Wallace]

But I don't think it's this year, and I disagree with Bob Wallace that it's almost certainly going to melt out in the next five years. I don't think anyone's made a water tight case that we're in for a fast crash rather than a tail (albeit not a long one like the models).

In order for there to be a tail we would need a very strong negative forcing and we have not identified any to date. 

It is possible that one might have appeared this year.  Massive fracturing of thinner ice may create a new weather pattern and the resulting cloud cover may change the melt rate. 

(I did hedge my 'five years' with 'almost'.  We're in brand new territory, there's room for strange to rear its head before we hit the end.)

The attempts I've seen don't address the key issue of more vigorous autumn/winter growth.

Is this most likely to be early season vigorous freezing but not a large increase in the final thickness of FYI?  Just a quicker acceleration but not a larger overall freeze.

[ChrisReynolds]

Bob,

From gridded PIOMAS data.



When seasonal thinning equals April thickness you get no ice. The same sort of graph can be calculated using volume loss.

Ice grows to 2m thick (approx.) with thermodynamic growth during the winter. Much of the decline in thickness in April is due to loss of MYI, we are near the end of that process, possibly as close as is practically possible without a complete melt out most years. It is quite feasible that the levelling suggested for 2011 and 2012 in April thickness is the start of us reaching a lower thickness limit imposed by the thermodynamic growth of ice over winter. If that is the case the ice could linger into the 2020s until winter warming is enough to cause further thinning of the thermodynamic winter thickness.

As for summer increase in thinning; the mechanism behind this also seem linked to the transition to FYI from MYI pack. In PIOMAS it is worth noting that while the thinning curve (% open water as a function of April thickness) shows some changes, all the years since 1979 show the same general form.



So the increase in thinning is probably in response to loss of thick ice bringing more of the ice into the large slope on that graph. Thus it seems likely that as well as a possible lack of winter thinning, the increase of summer thinning may be about to taper off.

[werther]

Evening Lodger,
Saw you commenting on Ktonine about the snow cover on the sea ice. I was struck by some graphs posted by A-Team four days ago:

The hatched area is what the Shizuku 6MHz "horizontally polarized ascending" band coloured as yellow.
I’ve layered this yellow area of this graph over MODIS same day. I’ve been figuring what the features might represent. I have a hunch they show albedo and thus an indication of the quality of remaining snow cover. Of course, yellow was deepest near the CAA.
If true, it may well cover what you posted on wet snow over the splinter-zone and the beaufort-Chukchi region. Quoting A-Team "...is not too affected by clouds..."

[Peter Ellis]

jdallen - why would lateral melt be dependent on floe size? I can't think of any physical reason for lateral melt rates to be different on a 50 meter diameter floe as opposed to a 5 km diameter floe. 

The rate will be the same, yes.  Melting 1 metre off the side of a 50 meter floe (i.e. turning a 50m square into a 48m square) means melting almost 8% of the ice.  Melting 1 metre off the side of a 5km floe is negligible, less than 0.1% of the total.

[Bob Wallace]

Ice grows to 2m thick (approx.) with thermodynamic growth during the winter. Much of the decline in thickness in April is due to loss of MYI, we are near the end of that process, possibly as close as is practically possible without a complete melt out most years. It is quite feasible that the levelling suggested for 2011 and 2012 in April thickness is the start of us reaching a lower thickness limit imposed by the thermodynamic growth of ice over winter. If that is the case the ice could linger into the 2020s until winter warming is enough to cause further thinning of the thermodynamic winter thickness.

It's possible.  But if FYI melting was slowing then we would see an increase in MYI, which we are not.



What we are observing is that as the ice pack thins the volume transported out the Fram stays roughly constant due to faster outflow.

Less BOY volume means that incoming solar, atmospheric, surface water and ocean heat has less ice to melt.  Less MYI means a pack easier to churn.

After the MYI is gone, post the first summer meltout, April thickness will likely slow to a plateau with a slight downward slope.  Over years the extent of the winter pack will gradually decrease as the ice boundary pulls back.  At the beginning of the melt season there will be no more but slightly less ice along with somewhat stronger melting forces in the wait. 

[Frivolousz21]

The 12z models are even more vigorous.

[Frivolousz21]

New 00z GFS continues to show the HP sit and spin.

[jdallen]

jdallen - why would lateral melt be dependent on floe size? I can't think of any physical reason for lateral melt rates to be different on a 50 meter diameter floe as opposed to a 5 km diameter

It has to do with the ratio of exposed surface to accessible volume;  the rate may be the same, but the rate of decrease in flow size will not.  Four .025 sq km flows will melt out more quickly than a single .1 sq KM flow.  Larger than that, side melt is much less significant factor in the reduction of floe size.

Side melt occurs with larger sizes, bur in net contributes far less to the reduction of SIA and volume.

Bottom melt OTOH,  given similar temperatures, will affect both large and small floes of the same thickness, to the same degree.

[jdallen]

jdallen - why would lateral melt be dependent on floe size? I can't think of any physical reason for lateral melt rates to be different on a 50 meter diameter floe as opposed to a 5 km diameter floe. 

The rate will be the same, yes.  Melting 1 metre off the side of a 50 meter floe (i.e. turning a 50m square into a 48m square) means melting almost 8% of the ice.  Melting 1 metre off the side of a 5km floe is negligible, less than 0.1% of the total.

I should read all the way through posts before responding. What Peter said

[jdallen]

The 12z models are even ....

The 850PA temp numbers are very depressing.  Add to that the heat and insolation blasting the weakened Beaufort, and I think we are in for a very bad week.

[Frivolousz21]

ITP 57 is showing bottom melt picking up from solar heating.

It's hard to see.  But the little squiggly line on the temperature graph means the water directly below the surface has warmed above -1.5C.  Looking at the composite profiles it look's like it's running about -1.35C or so.  The profile starts at about 8 meters.  So it may be slightly warmer right near the ice.

Since the warmth goes into melting ice.  It will quickly cool if it is not maintained.  So far it has maintained enough to stay in a melting phase.

Salinity slightly dropped below 33PSU.  This is inline with the warmer waters.  So fresher water appears to be mixed in a bit from melting. 

Considering how far North and close to the pole this is.  Given the current weather pattern we can assume ice further South towards the Laptev and Kara are experiencing stronger bottom melt.

[Frivolousz21]

ITP 58 also show's warming as well.

Both ITP 57 and 58 have only updated through 23z July 5th.  Currently this area is pretty warm.

[ChrisReynolds]

Bob,

No we would not see an increase in MYI, the amount of MYI is now primarily determined by the amount of ice left at the end of the season. Fram export is a sideline, it plays a role in the long term decline of MYI, but does not explain why the MYI has not been replenished, Fram export has always been a factor in sea ice dynamics, but hasn't led to the decline of the pack in past centuries.



That's a plot of <2m thick ice which is roughly equivalent to thermodynamic growth of FYI, and >2m thick ice which is roughly equivalent to mechanically deformed MYI.

What is going on here is that through most of the years FYI remains the same, while MYI declines. This shows that MYI is causing the volume loss, and FYI is not, which is because FYI can grow back in one season, whereas MYI having a longer lifetime (by definition) is subjected to loss of volume due to warming of atmosphere and ocean for many years.

Then in 2007 there is a massive melt of MYI, which opens Beaufort and Chukchi in following years, meaning that the Beaufort Flywheel no longer ages ice, ice transported into that region now melts out. What the above graphic doesn't show is that ice over 2m thick is reducing in thickness from 2007 onwards, despite volume over 2m seeming to decrease in two steps (2007 and 2009).

Then in 2010 there is another massive volume loss, which is only apparent in the April 2011 figure because most of the loss happened during 2010 after April.

What we have seen post 2007 and post 2011 is a levelling of >2m volume, this is in contrast to the clear trend of volume loss from the 1990s to 2006.

Looking at the percentage contributions to overall volume of >2m and <2m thick ice suggests that the previous trend of transition ceases in 2011 to 2013.

[Espen]

Svalbard is now being released from the ice pack.

[Frivolousz21]

The deadline for Arcus: Search SIO is Monday July 8th. 

So far Watt's hasn't posted a July poll on his blog.  I went to read the July forecast comment's and after about 10 minutes of searching and scrolling through June.  Which is not easy with the insane amount of posts.  I eventually found the June post and blog poll.

So far there isn't for one July. 

[Jim Hunt]

From a slightly different perspective Friv, here's a few thermistor profiles from IMB buoy 2013B, which is colocated with ITP 61, amongst other instruments. Not a lot of bottom melt visible as yet, but the floe does look to be warming through nicely.

Thermistor 1 is in the air above the ice. Thermistors  24-31 appear to be in the water underneath it. Current water temperature just under the ice reads -1.7 or thereabouts.

[Frivolousz21]

From a slightly different perspective Friv, here's a few thermistor profiles from IMB buoy 2013B, which is colocated with ITP 61, amonst other instruments. Not a lot of bottom melt visible as yet, but the floe does look to be warming through nicely.

Thermistor 1 is in the air above the ice. Thermistors  24-31 appear to be in the water underneath it. Current water temperature just under the ice reads -1.7 or thereabouts.

Yeah.  That one is nestled pretty far into the ice pack closer to GIS.  Looking at the upcoming pattern change it might be sent a bit closer to it's ultimate destination in the Fram.

[wanderer]

Two big area drops in a row:
http://arctic.atmos.uiuc.edu/cryosphere/arctic.sea.ice.interactive.html

If it would go on like this for the next 5 days 2013 would come very close to 2012

[Neven]

Yes, four century breaks in a row for CT SIA: 193K, 125K, 166K and 160K. 2013 now has as many century breaks as last year (32), but 2012 has another nice streak coming up next week.

[BornFromTheVoid]

Here's where we stand with regard to previous years minima.




EDIT: Oops, perhaps this should by the the Cryosphere Today thread!?

[werther]

Just as a ‘sidekick’ from what I’ve been doing on MODIS Beaufort Sea this morning, I thought to compare the shot I made 14 June of part of tile r04c04:
This was 14 June:


Now it is like this:



An image speaks for itself…

As for the Beaufort Sea:
Took a part of about 7200 km2 in what was open sea day 184 last year. Centered about 130 km W of the SW tip of Banks Island. I fished up 185 MYI floes (at least, they stand out from the lower albedo mélange). Their average area was less than 11 km2.
I think a big difference with last year in the Beaufort Sea is, that the February fragmentation/rotation events pushed this MYI in from the CAB while dispersing them.

Mind that the arbitrary boundary BS – CAB lies in front of the Mc Clure Strait, 300 km N of my count area.

Another aspect is, that all these MYI floes (same process spanning a zonal band from Banks to N of Barrow) belonged to the 1,8 Mkm2 remaining structural unity of the mesh-pack against the CAA. This dispersal means loss for that area.

Continuing the count; underlining the structural weakness of the Beaufort Sea ice cover are more than 150 open water polynia’s worth digitizing. Together, they don’t seem like much (less than 1% of the count area). But they represent the parts showing the most albedo loss. And while even the MYI floes are covered with wet snow/melt ponds (they show up as gray shades), it shows something…

What then, please?

See, the Beaufort Sea area is about 580K km2. Last year, about 300 K was open, this year about 100K.
The difference isn’t good, solid, countable area and extent ice. It is a mélange heading for melt out. The MYI floes, about 30% from 480K when I extrapolate the count zone, will last, maybe even until refreeze, that makes 174K.
The rest, rubble/floes smaller than 1,5 km2 isn’t a solid plate. It is broken up, forming pressure ridges (visible even on MODIS) and sloshing through winds and tide. It covers 72% of the count area. That goes for  345,6K (extra above the present 100K) melting out in the Beaufort Sea before the end of this season.

Thanks for remaining with me, I’ll try to fit this in an image later.

[Artful Dodger]

Thanks for remaining with me, I’ll try to fit this in an image later.

Thanks to you, werther! 

I think the melt trajectory in the Beaufort sea this year will determine if 2013 sets a new record minimum SIE. I believe it's already clear that the Eastern Arctic will have a gaping hole in the sea ice by the end of Summer, as your comparison above clearly shows the melt progression.

The question remains, what will happen in the Beaufort sea? At least one recent study cautions us to be watchful of this region:

Haas, C. (2012, December). Airborne Observations of the Distribution, Thickness, and Drift of Different Sea Ice Types and Extreme Ice Features in the Canadian Beaufort Sea. In OTC Arctic Technology Conference.

You may recall the "EM Bird" the Alfred Wegener Institute uses to measure sea ice thickness from the Polarstern research icebreaker? Well, this is the scientist that ran that program. For example, they participated in the ESA / CryoSat2 Validation program. In the paper above, Christian Haas says "Our results suggest a melt rate of ice islands of 10 m per year in the Southern Beaufort Sea." That's a graveyard!



Abstract:

Extensive airborne electromagnetic (EM) ice thickness surveys have been performed in April 2009, 2011, and 2012 over the Canadian Beaufort Sea with a long-range airplane. These are contributing to the Beaufort Regional Environmental Assessment (BREA) project which gathers ice information in preparation of a regulatory framework for safe and environmental responsible oil and gas production. Results show that the location of the multiyear ice edge can be very variable from year to year. Multiyear ice modal thicknesses ranged between 3.0 and 3.7 m. The seasonal ice zone had very variable ice thicknesses depending on the amount and age of ice formed in coastal polynyas and leads throughout the winter. However, we gathered enough data to show that modal first-year ice thicknesses of 2.0 to 2.2 m emerge if profiles are long enough, which can be considered the most representative first-year ice thickness estimate in the Canadian Beaufort Sea in April. However, in the seasonal ice zone also regions with heavily deformed ice thicker than 10 m, and occasional multiyear hummock fields of similar thicknesses occur. Results suggest that multiyear hummock fields may not comprise the thickest ice as they are affected by melt during the summer. Two ice islands had thicknesses between 20 and 30 m. Our results suggest a melt rate of ice islands of 10 m per year in the Southern Beaufort Sea. Ice thickness surveys were complemented by the analysis of satellite radar data and tracking of ice features by means of GPS beacons. We demonstrate that all these activities combined comprise a powerful tool for a future Arctic sea ice environmental observatory.

So indeed, enhanced sea melt in the Beaufort sea may allow for a new record low SIE in 2013.

[werther]

You're wellcome, Lodger.

Here is an illustration.

First, the Beaufort and my count area in context:



A detail of the count area with the MYI floes in the ugliest pink I could find:



The polynia’s don’t look like much, eh… but you see I may have missed a few…

And for now... off into the sun with a fine pint of beer!

[Jim Pettit]

Yes, four century breaks in a row for CT SIA: 193K, 125K, 166K and 160K. 2013 now has as many century breaks as last year (32), but 2012 has another nice streak coming up next week.

It's true that, after falling by 249k over the next four days, 2012 CT SIA dropped by a very healthy 869k over the next six days. But then it really stated leveling off, decreasing by just 811k over the next two weeks, for a 24-day (188-211) total decrease of 1.93 million. Given this year's slow start and resulting late catch-up, I'm of the opinion that 2013 will see a substantially greater loss during that span (maybe even enough to beat out 2002's record of 2.39 million). Perhaps not enough to catch 2012, but certainly enough to gain a whole lot of ground. Er, open water.

[roman_01]

Meanwhile in denier´s paralel universe:

http://stevengoddard.wordpress.com/2013/07/06/large-increase-in-arctic-ice-this-summer/

[Neven]

Thanks for some great images, Werther. I think I will use them for an ASI update I'm preparing, with the title 'Bye bye, Beaufort'.

For people who don't want to increase traffic to Steven Goddard's '10 words per blog post' blog, here's what he writes:

Green shows areas of ice present in 2013, but not present in 2012. Red shows the opposite.

The Beaufort Sea is the big problem for alarmists. In June 2012, wind opened it up early causing lots of solar energy to be absorbed and warming of the water. That didn’t happen this year, and with the sun starting its decline the opportunities for a big melt are getting slim.

If the Beaufort Sea is a big problem for alarmists, then how much of a problem is all of the Arctic sea ice pack for fake skeptics like Steven Goddard? I think it's a HUGE problem.

I'm expecting a lot of melting in the Beaufort in the coming two weeks. Hence the title of the next ASI update.

[ktonine]

There are a couple of interesting oddities/tidbits/milestones in the CT SIA data.  If we take 2007, 2010, 2011 & 2012 and consider them as a group - the melt out years - and compare them to 2013 we find that 2013 is about 8 days behind 2010 and 6 days behind 2012 as far as the day of year to reach 2013's area on day 186 (6.87 Mkm^2).

All of the melt out years crossed the 6 Mkm^2 mark on day 191 +/- a day.  They diverged over the next 20 days, but converged again so that they all passed the 4.5 Mkm^2 mark within a couple days of day 211.  It was only after day 211 that 2012 really separated itself from the  others. 



In a normal year I would find these numbers compelling enough to guess that 2013 is unlikely to exceed *any* of the melt out years.  But this year has such a different pattern to the melt I'm not willing to go there yet.

The CT SIA graph shows that even on August 1st it's difficult to predict the final result.  Has 2013 seen the ice preconditioned for a blow out over the final 6 weeks - or is it just a different melt pattern with no really discernible effect on the final result?

As many others have noted, regardless of where 2013 ends up in relation to other years it has provided a very interesting melt season. 

[seawolf]

With all due respect Werther, that image comparison of small area of Central Arctic might be misleading, since the ice is drifting, and where there was more compacted ice two weeks ago, a hole may appear now (and vice versa). Zooming out, not much difference in overall open-water area can be observed by naked eye (though typical floe size might be getting smaller, floes breaking up?). The CT SIA numbers for Central Arctic didn't change very much over the past 2-3 weeks in fact.

Sun heat and open water in the periphery will melt these floes faster. End July - August?

[Frivolousz21]

Thanks for some great images, Werther. I think I will use them for an ASI update I'm preparing, with the title 'Bye bye, Beaufort'.

For people who don't want to increase traffic to Steven Goddard's '10 words per blog post' blog, here's what he writes:

Green shows areas of ice present in 2013, but not present in 2012. Red shows the opposite.

The Beaufort Sea is the big problem for alarmists. In June 2012, wind opened it up early causing lots of solar energy to be absorbed and warming of the water. That didn’t happen this year, and with the sun starting its decline the opportunities for a big melt are getting slim.

If the Beaufort Sea is a big problem for alarmists, then how much of a problem is all of the Arctic sea ice pack for fake skeptics like Steven Goddard? I think it's a HUGE problem.

I'm expecting a lot of melting in the Beaufort in the coming two weeks. Hence the title of the next ASI update.

The models keep the High Pressure in a position where ice in the Canadian Arctic Basin will be sent towards the Beaufort.  While it will be pretty warm and sunny.  I doubt in this set up the Beaufort will be very large reductions.  The trade off is the extra room for compaction around the other side of the HP.  The central arctic basin, laptev, ESS will see the most noticible differences.

There is almost no chance with ice being blown towards the Beaufort in this set-up(Which is also a lot of MYI) to boot.  That the Beaufort will see very much open water over the next two weeks.

[ktonine]

There is almost no chance with ice being blown towards the Beaufort in this set-up(Which is also a lot of MYI) to boot.  That the Beaufort will see very much open water over the next two weeks.

friv - remember that sea ice does not move very fast.  As an example, it has taken buoy 2012H ten months to move five degrees of latitude.  http://imb.crrel.usace.army.mil/2012H.htm For short term predictions we can assume the ice is stationary except for local compaction/divergence.

The prospect for open water in the Beaufort over the coming weeks should be due to in situ melting.

[Jim Hunt]

Meanwhile in denier's parallel universe:

Having a little fun at the expense of the second dumbest man on the internet:

"How to upset a global warming sceptic"

[roman_01]

"Having a little fun at the expense of the second dumbest man on the internet:"

So there is someone even dumber? I don´t think so 

[jdallen]

Bob,

No we would not see an increase in MYI, the amount of MYI is now primarily determined by the amount of ice left at the end of the season. Fram export is a sideline, it plays a role in the long term decline of MYI, but does not explain why the MYI has not been replenished, Fram export has always been a factor in sea ice dynamics, but hasn't led to the decline of the pack in past centuries.

Thank you Chris.  Nicely illustrated.

[jdallen]

... Not a lot of bottom melt visible as yet, but the floe does look to be warming through nicely.

Thermistor 1 is in the air above the ice. Thermistors  24-31 appear to be in the water underneath it. Current water temperature just under the ice reads -1.7 or thereabouts.

In fact, the first *4* thermistors appear to be above the ice, with the 5th close to being as well.  That implies some fairly significant top melt (~50CM); perhaps snow disappearing, but probably some ice as well.

[wili]

Ktonine, nice observations on CT SIA graph. My WAG is that this year's line will join the others somewhere in the area of your blue circle, then break below (or tie for that positions) somewhere in or near your green circle.

(Egg, prepare to meet face.)

[werther]

Sea Wolf, hi,
Of course it is misleading. I know it represents a temporary state in an ever changing theatre. But, as my casual eyeballing gave me the impression the overall scene is worse than 14 June, I thought it appropriate to post.
Whatever, I found a 440 km2 floe not far from its original position 2% smaller than 20 days ago. I suppose boundary melt to be fairly illustrated by that. And while the boundary of that floe melted about a hundred meters, one can imagine a 1,5 km2 rubble floe  to have suffered a 35% loss in area. Exactly what the pic supposes to illustrate.
And that excludes bottom melt which is not possibly assessed through MODIS. But I’m sure the volume loss is more than the 2% area loss…

On the Beaufort... you're right Friv, the forecasted high won't immediately waste the Beaufort. It is insolation that might make a difference.

[Frivolousz21]

THE 00Z EURO SAYS KING KONG AIN'T GOT SHIT ON ME!


This is setting up to be a potentially epic about face.  The losses may not come big until day 4-5 when the winds crush, compact, compress the ice from the Chuchki to ESS and ESS to Central arctic basin and Eastern Laptev, Eastern Laptev to Central arctic basin and Western Laptev towards atlantic side central arctic basin around the weaker SLP.

Did I mention scorching warmth will be pulled off each continent while the HP clears out a gigantic region receiving 475W/M2 to 500W/m2 at the pole.  Which is about to drop.  But on August first 70-90N is still getting 425W/M2.  Land heating is reaching the yearly max.  This HP is huge.  The sun doesn't set.  It does get weaker indeed in the 70-80N  range.  But that is not weak enough when on top of essentially upwards of 5+ million sq/km2 of ice area getting near clear skies for days on end as well as huge warm air advection from the land.  The melt after 3-4 of this will take form as incredible near basin wide bottom melt.  This is a rare bird.   

[Neven]

One would expect the AO ensemble forecast to go down somewhat, but nope:

[Jim Hunt]

In fact, the first *4* thermistors appear to be above the ice, with the 5th close to being as well.  That implies some fairly significant top melt (~50CM); perhaps snow disappearing, but probably some ice as well.

Unfortunately we have to speculate about this somewhat. The 2013C page states that:

Thermistor #7 at air-snow interface (7 cm above ice-snow interface)

but that doesn't mean all the buoys are set up that way, and no such information is available for most of them. BTW 2013C is near Alert, and is showing some surface melt.

The other sensors on 2013B are all working and showed no snow on June 1st which has since increased, no surface melt currently, but 2 cm of bottom melt over the last couple of days.

[werther]

CT is in day 167 / 16 June; another century...minus 127 K. first of a 20-day range?

Well... the range didn't get to -150 a day... but this was an impressive ride!
One more SIA/CT number to go, passing 2 million km2 of losses.
For SIE, the range is in; losing 97K a day reminds of first week July '07. Worse, '13 beats that week!
The numbers are getting in line with what MODIS is showing.

So, you'll say... that was Hudson, Baffin, Kara.

OK, but ECMWF/GFS are calling for THE HIGH!

[werther]

OK, I just saw CT coming in with a remarkably low 25K loss yesterday.
As far as the number-crunching is amusing, that takes my supposed 20-day range over 2Mkm2.
A mean loss of 101K/day.

[wanderer]

Lots of cracks, some new, some older, difficult to spot between the clouds: http://earthdata.nasa.gov/labs/worldview/?map=-1166080,-353280,-343296,248320&products=baselayers,MODIS_Terra_CorrectedReflectance_TrueColor~overlays,arctic_coastlines_3413&time=2013-07-08&switch=arctic

[Phil.]

Look at the low concentration ice floes in Modis - they appear to be snow covered - very white.  Contrast them to what we see in the marginal ice zones around the Beaufort. The north Pole webcams show it still snowing in one location - even though water can be seen in the background. The two north pole webcams aren't in the very low concentration areas, but I think they're probably representative of coloration (albedo) if nothing else.

The edges of floes will be splashed with water - hence the lateral melt, but even the smaller floes visible on Modis are hundreds of meters in diameter. 

With air temps below zero and generally cloudy skies would you expect top melt?  Have you any evidence of top melt in these areas?

If you look at the 6 black and white objects emerging from the ice in the foreground of webcam#1 in today's image and compare them with a couple of weeks ago they're obviously protruding more now.  I would think that is evidence of surface melt/sublimation?  Also the open water beyond the buoy in webcam#2 appears to be growing.

http://psc.apl.washington.edu/northpole/NPEO2013/8.jpg

[ktonine]

Phil - yes I've been monitoring the stakes.  I think if you look back through the archives you'll find almost no change until the last bout of precipitation.  The temperatures also just in the past few days went above zero.