Arctic Sea Ice Discussion 2016: Melt Season

[BornFromTheVoid]

8 hours ago, Geordiesnow said:

Very interesting image, I think the uncertain nature of this storm and its impact that its going to be a cold storm in the most part whereas in general, the 2012 storm had more warmer air mixed in within it. 

I think if we had an ice pack looking like 2014 or even the ice pack of 2013, I don't think this storm will cause too many negative affects but this years pack just look so vulnable so you do fear what could happen, could the unusually cold uppers be a saviour?

I see a lot of people mentioning that GAC 2012 was a warm storm and this will be a cold one. To me, there are 2 factors that matter in this regard:

1. Are the air temperatures with this storm much cooler than in 2012?
2. Do the air temperatures matter that much with late season storms?

For 1, we can compare the ECM upper air temps and see if there's much difference.

First the storms themselves

............ ...................2012 ............... .................. ................2016

 

Both appear very similar, with 2012 being just a little more compact and closer to the Pacific than 2016.
Next, the 850hPa temps

............ ...................2012 ............... .................. ................2016
 

The distribution of cold is quite different on the 2 storms, with 2012 having slightly more widespread cold, but less deep. 2016 is certainly a bit colder over the central Arctic, however, I'm not sure if the difference is enough to call one a warm storm and one a cold storm.

As for the importance of this cold difference, I don't think it matters much. At this time of year the main destructive action from this storm will be through waves, swells and warm water upwelling. A little rain would have helped speed up melt a bit, but I don't think the additional snowfall will help the large areas of low concentration ice much. The air is still not cold enough to produce fresh sea ice, despite being cold enough for snow over some areas and refreezing of melt ponds (dependent on the wind too).

2012 did, and 2016 will, take a direct hit to the areas with the weakest most fragmented ice of the season so I think the effects of the storms overall will be quite similar. However, 2012 had more fragile ice leading up to GAC2012, so while I expect well above average melt rates for a few days this year, I don't think we'll come close to achieving a >1,000,000km2 in 7 days like we did in 2012.

..............Aug 3 2012 .....................Aug 12 2012

  

Edited August 13, 2016 by BornFromTheVoid

[Geordiesnow]

Too me this storm does look quite a bit colder and it pulls in less warm air ahead of it, as you say though the strength of the winds could play a significant role in all this and whilst the upper air temps are forecast to be cold, the strength of the wind could start mixing that cold air out at the surface. 

It will be really interesting how this will play out because there are some differences between this storm and the 2012 storm and it may therefore have a different affect on the ice than in 2012. 

[Nouska]

Mercator site projection for ice loss in the next six days.

Now   19th

http://bulletin.mercator-ocean.fr/

Nice animation of the forecast.

http://globalweatherlogistics.com/seaiceforecasting/gfs.850mb.height.vort.atlantic.html

 

Edited August 13, 2016 by Nouska

[Singularity]

The ECM 12z gives the storm a second wind in the 7-8 day range as its core pressure drops back down to 975-980 after a couple of days at 980-985. That's a manner of persistence that again brings back memories of 2012.

Seems we will seriously be in need of a year like 2013 to amend for this melting season... anyone know the odds?!

[Geordiesnow]

1 hour ago, Singularity said:

The ECM 12z gives the storm a second wind in the 7-8 day range as its core pressure drops back down to 975-980 after a couple of days at 980-985. That's a manner of persistence that again brings back memories of 2012.

Seems we will seriously be in need of a year like 2013 to amend for this melting season... anyone know the odds?!

Details like that are well beyond the reliable timeframe but obviously one too keep an eye on. The models are struggling with the details of where this storm will eventually settle once it forms over Laptev it seems to head more towards the pole rather than towards the arm of fragiled ice although of course there will still be effects from the storm with strong winds and waves. I think the main danger for that arm of fragile of ice will be as the storms leave laptev and more towards the pole, a surge of strong warm Southerly winds is heading right into that direction before things turn colder. 

Unlike in 2012, once this storm passes, the outlook seems to suggest it will be quite cold whereas in 2012 warm southerly winds headed into the Arctic from Alaska which no doubt meant the ice edge was pushed ever Northwards. 

I am looking forward to this storm arriving and seeing the impacts it will have on the ice because as I mentioned in my previous posts, there are differences between this storm and 2012 and we are 7-10 days closer to the end of the melt season which as far as temps in the Arctic goes can be a bit of a difference. I stand by my comments that this is more of a cold storm than it was in 2012, yes there is some warmer air initially but the air over the Arctic before this storm arrives is colder than it was during 2012 and it will be colder during the storm and more than likely after the storm. Will the cold air help the sea ice more than what some are expecting or will it have little difference and winds and SST's overrides any cold air? It got to be said, the SST's in Laptev going by the maps on Nevan's blog don't look all that warm too me but someone may correct me on that one. 

Edit: Those charts BFTV showing the archives for the ECM looks like has quite a bit colder uppers than the GFS model achieves on Wetterzentrale shows, whilst you might see a bit of variation between models, it's still quite a difference although I probably would trust the ECM uppers than the GFS's in all fairness.

Edited August 13, 2016 by Geordiesnow

[BornFromTheVoid]

 

...Diff..... ....No of Years ......Percentage
Below........ ......26......... ......70.3%
0-100k..... ........1......... ........2.7%
100-250k..... .....0......... ........0.0%
250-500k..... .....1......... ........2.7%
500-1000k..... ...3......... ........8.1%
>1000k..... ...... 6......... ........16.2%

[Singularity]

The Nullschool tool now has the storm at 969 mb which is just three short of the lowest numbers I've seen with respect to the GAC of 2012.

Quite a swathe of winds running along the borders of the Arctic basin now, terminating at the point where warmth and moisture is being drawn in from NE Asia along a frontal boundary.

The highest sustained winds I can find are at 43 mph. That's on a par with strong winter storms in the UK (though not the strongest by any means; I've seen estimates from this tool exceeding 60 mph).

[Singularity]

http://www.theweatheroutlook.com/twodata/chart.aspx?chart=/charts/ecm/216_mslp500_arc.png?cb=497

The models are coming together now on a potential second intense cyclone in the 8-10 day range. The seed for this first becomes evident in 6 days as it moves along the N. Eurasian coast. It then meets the cold pool in the Arctic and... Bang.

Some ensemble members from various models are showing storms in the 950s mb which would be extreme to say the least. It's alarming that a storm similar to the current one is now at the more positive end of the range of more probable outcomes based on ensemble distributions.

[BornFromTheVoid]

Big drop on the NSIDC daily extent, -112k.

Single day extent is now less than 400k off the 2009, 2013 and 2014 minima.
5 day trailing average extent is less than 500k off the 2009 and 2013 minima, and just over 500k off the 2014 minimum.

[weirpig]

1 hour ago, BornFromTheVoid said:

Big drop on the NSIDC daily extent, -112k.

Single day extent is now less than 400k off the 2009, 2013 and 2014 minima.
5 day trailing average extent is less than 500k off the 2009 and 2013 minima, and just over 500k off the 2014 minimum.

Do we still think 2012 is out of reach? The conditions in the artic do seem quite bad also a second storm may be brewing 

[BornFromTheVoid]

4 minutes ago, weirpig said:

Do we still think 2012 is out of reach? The conditions in the artic do seem quite bad also a second storm may be brewing 

Yep, still out of reach I'd say. The later the storms are, the less effect they'll have. The Arctic is beginning to cool down now too, and that cooling will really accelerate once we hit September. On average, the minimum is reached on September 12th, and we're currently 2 million km2 off the 2012 minimum, so it doesn't leave much time.
The most ice that's ever been lost from now til minimum is 1.6 million in 1999, so we'd need to really smash that record to catch 2012

[Singularity]

ECM 12z Det. Run Predicts An Exceptionally Stormy Arctic

Having watched the model output for the Arctic closely in recent days, I can report that this latest ECM run - detailed step-by-step below - has increased the intensity of the Arctic Low on many of the next 10 days, including in the 7-10 day range when there is the potential for a storm even more intense than the one that we have witnessed peaking today.

I'm not so sure about 2012 being out of reach as BFTV is. This is because I am wary of the potential for the oceanic impacts to prove more important relative to the atmosphere than many might expect. I'm not saying that this will be the case, just that it might, and that this IMO puts 2012's record at risk, albeit still at a long stretch.

 

Now - the whole ECM run in 24 hour intervals, with charts courtesy of TWO (Netweather could really do with improving the resolution of the pressure fields displayed on their N. Hemisphere output).

      

The first image is today's analysis chart, showing the currently active powerful storm as a point of reference. The innermost isobar is still 970 hPA, which is the same as was being shown for 24 hours ago. So the storm has spent at least 24 hours at sub-970 hPa core pressure. No wonder the SIE took such a big hit yesterday - and it probably has today as well.

The second image has the storm's core pressure still below 980 hPa at 12z tomorrow, which means we're looking at a storm persistent enough to realise much of the potential ice motion beneath it. As far as I know only the GAC of 2012 has been recorded as having greater persistence than this.

The image for 12z Thursday continues to gradually weaken the storm, but notice the secondary feature on the Pacific side. I can't recall seeing such a feature on previous ECM det. runs. 

The fourth image shows that secondary low at a little below 985 hPa at 12z on Friday, but at this time it's positioned over the relatively solid ice that borders Canada, so I imagine the direct impacts of this particular feature would be minimal.

   

12z Saturday is predicted to see this new storm making it to below 980 hPa, but staying close to Canada. It needs to be watched on future runs, in case it's position is adjusted to be further from Canada/Greenland, where it could prove more damaging to the ice. It is, after all, travelling in that direction - as the chart for 12z Sunday makes clear. Amazingly, the storm is still sub-980 hPa despite it's small size - it seems the enormous horizontal thermal gradients are enough to fuel such compact yet strong systems this season. Not only is that storm still going, but there's a secondary low as well, which threatens to merge with the mature one.

Chart number 7, for 12z Monday, shows that mercifully, the two systems have not merged and as a result are weakening - but there's already a seed on the scene for the next system. This time it's on the Asian side of the Arctic - which is where the seed for our current sub-970 hPa system originated.

The next chart depicts a complex situation, as the two mature lows continue stubbornly onward, while the new 'seed' has deepened rapidly - dropping 25 mb in the space of 24 hours (a ' meteorological bomb'). You can probably imagine the consequences of this storm interacting with the other two... brace yourselves!

  

That for 12z Wednesday is a sub-960 hPa low with an outlandishly steep pressure gradient around it. The presence of a ridge Canada-Greenland is an unwelcome sight in this regard.  If this storm continues to be modeled and of course verifies at an intensity similar to this, I will be impressed at the capability of current NWP models; GFS toyed with a sub-960 hPa low  yesterday, and CMC had a go as well. ECM is just a little late to the party (so to speak... this storm is not something to celebrate).

24 hours later, and the storm is still at sub-970 hPa core pressure. I struggle to comprehend what level of turbulence and mechanical hammering the ice would be going through beneath such a system. Meanwhile, the seed for yet another intense storm has arrived on the scene... this time passing over the +8*C SST anomalies in Barents/Kara.

Finally, the run finishes with the mature storm still at sub-975 hPa, and the new 'seed' heading below 985 hPa before it's even started to combine with the mature storm. Meanwhile, another wave disturbance is making an entrance from the Atlantic side. Going forward this could feasibly generate an even more intense low than already seen in this run.

 

Of course, the usual caveats apply - particularly that model uncertainty seems to have a tendency to escalate rapidly beyond around +5 days range when it comes to Arctic weather patterns - but what we're seeing being explored in runs such as this are the probable consequences of having a well established pool of cold air in the high Arctic that's interacting with a combination of surplus heat and moisture fluxes from extra expanses of open water and - perhaps more importantly - a mid-high latitude atmosphere that seems very keen on directing wave-trains right up into the Arctic Basin.

All this leaves me wondering what it was that stopped 2012 from such rinse-and-repeat behaviour - if anyone has an answer to that, I will greatly appreciate your input 

 

[stewfox]

3 hours ago, BornFromTheVoid said:

Yep, still out of reach I'd say. The later the storms are, the less effect they'll have. The Arctic is beginning to cool down now too, and that cooling will really accelerate once we hit September. On average, the minimum is reached on September 12th, and we're currently 2 million km2 off the 2012 minimum, so it doesn't leave much time.
The most ice that's ever been lost from now til minimum is 1.6 million in 1999, so we'd need to really smash that record to catch 2012

Yes we can see it here. A earlier drop of.

http://ocean.dmi.dk/arctic/meant80n.uk.php

Not sure why folks think late August storms will have such a major impact in or out of the basin. We will see , will end up 3rd or 4th lowest my guess. cant see where a  2 million loss is coming from

[BornFromTheVoid]

The storm is certainly having it's impact now, a drop of 109k on the ADS (IJIS) extent. That's the 4th largest drop for the 2nd half of August, largest for the date, and takes the current extent below every minima before 2007, and just 120k off the 2009 minimum.

@stewfox I think these days people have come to expect the unprecedented in the Arctic. In normal circumstances, expecting to see the late season ice loss record smashed by a large margin would be foolish, but we know that all kinds of records are being broken in the Arctic these days so expecting more isn't really all that odd.

@Singularity I certainly wouldn't rule out a new record, I just think it unlikely at this stage. If the current storm and the forecast for more storms was 10-14 days earlier, I'd see things a bit differently. The forecasts over the Arctic are often less reliable than our tricky location as you mentioned, so I will be taking those storms at 6 days + with a pinch of salt.
From about tomorrow onward, within the reliable timeframe, the forecast ain't too bad for the Arctic. A moderate depression, cloud and cold vs warmth brought to the surface through Ekman pumping from the current storm - it will be interesting to see which wins out.

Edited August 17, 2016 by BornFromTheVoid

[Singularity]

Yes it does look like a relative breather over the next few days, so we could attain some idea as to what manner of intertia the bottom-melt has post-churning of the waters.

ECM has a couple of 975 hPa storms instead of one sub-960 storm so the uncertainty is very much in evidence. All we can really go with is a theme of persistent deep cyclonicity, perhaps focused on the Pacific side again once past the next 4-5 days.

Cold air might help preserve the scattered ice... but could snow cover insulate that ice from the air while it continues to melt at the bottom? This is so complex... We stand to learn a great deal this month.

[BornFromTheVoid]

Some incredible flash melting visible on Obuoy 14

................August 12th ..................................... ..............August 15th.........................................August 16th
  

 

And this morning!

[Gray-Wolf]

Due to lots of ice being FY ice we must have huge stretches just like the ice around obuoy14? Extent/area just show us we have ice there but does not tell us if it's 1m or 10cm thick? 

Could there be a large portion of the 2 million required to overtake 2012 just readying itself for blink out?

The biggest worry must be overwash? With so much ice now very low in the water ( freeboard less than 10cm) then any sustained 40mph winds will raise quite a chop exposing all surfaces to high melt forcings.

[BornFromTheVoid]

With a drop of 136k, the daily NSIDC extent has dropped back to 2nd lowest for the first time since July 7th.
Just 263k required for the daily extent to drop below the minima of 2009, 2013 and 2014.

[stewfox]

11 hours ago, Gray-Wolf said:

Due to lots of ice being FY ice we must have huge stretches just like the ice around obuoy14? Extent/area just show us we have ice there but does not tell us if it's 1m or 10cm thick? 

Could there be a large portion of the 2 million required to overtake 2012 just readying itself for blink out?

The biggest worry must be overwash? With so much ice now very low in the water ( freeboard less than 10cm) then any sustained 40mph winds will raise quite a chop exposing all surfaces to high melt forcings.

Cant seem to find the thickness charts ?

[BornFromTheVoid]

Just an animation of before and after the storm. The rotation in the pack is really noticeable for just 3 days.

[weirpig]

13 minutes ago, BornFromTheVoid said:

Just an animation of before and after the storm. The rotation in the pack is really noticeable for just 3 days.

Interesting  taking a bit of a battering   does the darker the colour indicate the thickness of the ice?

[BornFromTheVoid]

16 minutes ago, weirpig said:

Interesting  taking a bit of a battering   does the darker the colour indicate the thickness of the ice?

It's the concentration, which is the percentage of ocean surface in each pixel covered by sea ice. The legend is along the bottom. So the areas that are purple are almost entirely covered in ice, and the the greenish areas are only half to 3/4s covered.
We don't get daily thickness observations from satellites, so any of the daily thickness products show big differences due to how the ice is modeled and aren't considered very reliable.

Edited August 18, 2016 by BornFromTheVoid

[Gray-Wolf]

Well I hope the dark purple doesn't continue on its current trajectory or we'll lose it to fram by monday!!! 

[BornFromTheVoid]

ADS extent had already dropped below every previous minimum up to and including 2006 and, after yesterdays drop, is now below 2009 too.

[weirpig]

this is taken from another site  but does seem to show a part of the ice could detatched itself over the next few weeks   if so  how much impact would that have on the overall ice loss?