2016 melting momentum, part 2

Happy Solstice, everyone!

Credit: NASA/Kathryn Hansen

The previous post on melting momentum was running long, so here's an addition dealing with compactness, the final piece of information we have to assess the amount of melting momentum. Just before the start of July, the month of big melt. First, a couple of paragraphs to explain what compactness is and what it can tell us.

Not only melt ponds, but also open water between ice floes can absorb solar radiation, heating up the water, and then speeding up the melt process. We can get an idea of how compact an ice pack is by dividing sea ice area numbers (SIA) with sea ice extent numbers (SIE), the products of two different ways of measuring total sea ice cover.

The idea is simple, really. The Arctic is divided into grid cells, and each grid cell has a certain sea ice concentration. On the right there's an example of one such grid cell, with white representing ice and blue representing open water/melt ponds. This grid cell measures 10 x 10 km, and thus has a total area of 100 km2. Sea ice concentration is 80% in this grid cell, which means that 80 km2 is covered with ice. This is the number that represents sea ice area.

However, for sea ice extent there's a so-called threshold of 15%, meaning that if there's 15% of sea ice concentration or more, the entire grid cell is considered ice-covered. In other words sea ice extent for this particular grid cell is 100 km2. The reason for this different way of assessing total ice cover is to reduce the influence of melt ponds, that can fool satellite sensors into 'thinking' they're seeing open water.

That is why sea ice area will always be lower than sea ice extent. If we now divide SIA by SIE, we get a percentage that gives us an idea how much open water/melt ponding there is between and on ice floes. The grid cell's compactness ratio in this example is 80/100=0.8. This, of course, can be done for the entire Arctic.

Different data sets can be used to calculate compactness. For years I have used Cryosphere Today SIA data and divided it by IJIS sea ice data (CAPIE = Cryosphere today Area Per IJIS Extent) and used these graphs for the ASI updates. As IJIS no longer reports SIE data from the Japan Aerospace Exploration Agency, or JAXA, the name has changed to CAJAX. Here's the latest graph:
Just a few weeks back, 2016 had the lowest CAJAX ratio, but now it's firmly in the middle of the pack. Based on what we know from the previous Melting momentum blog post and the latest ASI update, we can safely say that a lack of melt ponds is being compensated by open water between ice floes, for instance in the Beaufort Sea (source: Environment Canada):

As there are more data sets out there, I've decided to try something else as well as an experiment. Bear with me.

Grid cell size can vary from data set to data set. This is called resolution. The higher the resolution, the smaller grid cells are, the more accurate SIA or SIE is. I figured that if I used SIA at a low resolution, grid cells will be big and thus melt ponds and leads will have a larger impact on the numbers. If I then combine this with high-resolution extent that does the opposite - reduce the impact of melt ponds and open water between floes - I get a much more pronounced compactness ratio.

This is all a bit counterintuitive and I'm not going for the accuracy award here, as I want changes to be as exaggerated as possible. In fact, it's probably the completely wrong thing to do, as data sets not only have different resolutions, but also use different sensors, land masks, algorithms, and so on. But what the heck.

I used Cryosphere Today SIA (25 km resolution, as calculated by Wipneus until calibrated data is published by Cryosphere Today) and divided it by MASIE sea ice extent numbers (4 km resolution). Yes, I'm even combining a passive microwave product with an operational analysis product (difference explained here)! Like I always say: If you're already breaking the law by jaywalking, you might as well rob the bank too. ;-)

The good thing about MASIE is that it's one of the most precise data sets out there as it is based on the IMS sea ice product, which is updated daily by analysts from the National Ice Center - people, not automated scripts - who look at a plethora of satellite imagery to determine where the exact ice edge is. The downside of that is that there's a subjective component (different analysts) and changes in available satellite data over time. That's why in principle MASIE isn't deemed consistent enough for long-term trends.

I have found, however, that MASIE seems reasonably consistent after 2010 or 2011 (a change in data sources around that time causes years prior to have a low bias for most of the year), so I present to you CAMAS:

You can see that the spread between trend lines is much larger after day 210, and 2012 goes extremely low compared to the rest. That's because the Great Arctic Cyclone caused the ice pack to disperse so much that Cryosphere Today SIA went nuts, whereas MASIE of course kept 'seeing' all the ice. This is what I mean with exaggerated changes in compactness.

Either way, 2016 is somewhat lower here, relatively speaking, but far from the lowest (and 2007 isn't even included in this graph).

If you're a purist and want to see compactness graphs that actually deserve the moniker because both SIA and SIE data come from the same source (meaning everything else is the same), you can check out this graph that Wipneus updates every day (see ASIG Regional Graphs page), based on data from NSIDC (25 km resolution), JAXA (10 km resolution) and Uni Hamburg (3.125 km resolution):

Here, 2016 currently has the highest compactness ratio in all three different segments, indicating that the ice pack is relatively compact (few melt ponds) and little melting momentum is being built up to boost melting during July and August.

Long story short: Even though 2016 has been breaking records all year so far, as things currently stand, it will take special weather conditions for it to break any records near the end of the melting season.

Comments

[Villabolo]

Neven:

"Long story short: Even though 2016 has been breaking records all year so far, as things currently stand, it will take special weather conditions for it to break any records near the end of the melting season."

I've seen the polls but I'm curious to know how much of an extent you think we're likely to have come mid September.

[Jim Williams]

"Long story short: Even though 2016 has been breaking records all year so far, as things currently stand, it will take special weather conditions for it to break any records near the end of the melting season."

OK...then the simple question is: why has it been breaking records all year so far?

[Hans Gunnstaddar]

https://www.climate.gov/news-features/blogs/enso/may-2016-el-ni%C3%B1ola-ni%C3%B1a-update-switcheroo

Neven, good analysis and creative method sought for greater clarification of 2016 melt update. The article linked above is on the switching from El Nino to La Nina predicted for this Summer as ocean temps are currently cooling. I'm not saying that's why 2016 melt has gone from record setting to much less likely to break any records, but it's worth considering.

[navegante]

Thank you great post as always.
About evaluating the current compactness right now, I am just looking at the plots, and differences of today's values are within noise levels. However big changes happen from this time of the year until July 10.
Perhaps you are factoring in the coming weather. In the forum you explain it mighy remaing favorable for ice.

[Rob Dekker]

Thank you Neven, great post, but I'd like to add a few notes.

When I look at the "regional graphs", I noticed that for the Central Arctic Basin (CAB) (the area where the September minimum will end up) that "extent" in 2016 is about the same as it was in 2012, but "area" in 2016 is lower than 2012. Which suggests that in the CAB the ice concentration at this time is LOWER than it was in 2012.

That kind of makes sense, when you look at the fragmented mess of the CAB that has been feeding the mess in the Beaufort over the past month, and also the fragmented ice in the CAB that is still moving into the area North of Svalbard.

So what caused the ice concentration to be higher now than it was in 2012 ? If you look at the regional graphs, only the Laptev appears as clearly having a higher area/extent ratio at this time. That's probably because this year the Laptev did not melt as quickly as in 2012.

Other than the Laptev, 2016 is still ahead of next runner up 2012 for extent. And ice concentration in the CAB is still below 2012.

[Neven]

I've seen the polls but I'm curious to know how much of an extent you think we're likely to have come mid September.

Well, in the recent June poll I have voted for 'between 4.0 and 4.25 million km2 (2012, 2007 and 2011+2015 ending at 3.63, 4.30 and 4.63 million km2 respectively. Given current conditions and forecasts I might be tempted to go one bin up to 'between 4.25 and 4.5 million km2', but there's still some weeks left to go before the July poll opens up.

There has to be one or two periods of weather conditions that are conducive to melting for this year to end up in the top 3.

On the other hand you could say that it is already quite remarkable for this year to still be so low despite weeks of weather that is good for ice retention.

OK...then the simple question is: why has it been breaking records all year so far?

Because of winter weather and weather conditions until they switched a few weeks ago (when weather conditions perhaps matter most for the melting season outcome). And there's always the wild card: ocean heat flux.

The article linked above is on the switching from El Nino to La Nina predicted for this Summer as ocean temps are currently cooling. I'm not saying that's why 2016 melt has gone from record setting to much less likely to break any records, but it's worth considering.

Even if there was a correlation between ENSO and Arctic sea ice - which there isn't, as far as I can see - there is no way it would be this direct.

In the forum you explain it mighy remaing favorable for ice.

Well, the forecasts keep flip-flopping. Now they've returned to forecasting domination of high pressure over the American side of the Arctic. If these areas push towards the Central Arctic, that 'mess in the Beaufort', as Rob Dekker aptly calls it, is going to be struck hard. This is important with regards to longer-term trends, as there could be very little multi-year ice left at the end of the melting season.

There will also be more transport towards the warm Atlantic and more compaction, and so on. Like I said, just a few weeks of such weather and 2016 can still make it to the top 3. It's going to take an exceptionally warm and sunny July though (like we saw last year) for 2016 to become a title contender again.

[Rob Dekker]

Let me add that I don't challenge Neven's statement that " it will take special weather conditions for it to break any records near the end of the melting season.".
In fact, for SIPN/ARCUS I entered 3.8 M km^2 as the most likely September 2016 average extent.

But I'd like to caution against being overly conservative. The state of the ice in 2016 is not good at all, and with albedo feedbacks, the Arctic is right now much more sensitive to weather than it has ever been, so if even an average summer gets us to 3.8, a bit of melt-inducing weather will easily get us much lower.

[DavidR]

I like the idea of using MASIE as the area measure for compactness. Using just extent and area ignores cells within the pack that are ice free. What can be seen from the satellites at the moment are many patches of open water within the pack. Assuming these have no ice they would not be included in SIE or SIA. But they would still be allowing warming via albedo further within the pack than usual. As a consequence it would be easier to melt out the CAB than usual.

[NeilT]

I like a little bit of history.

https://nsidc.org/arcticseaicenews/2006/

I love to look back at the graph to see the

2005 Record Low
The baseline for melting of 1979 - 2000

And that polynia on Sept 11th was quite interesting.

More interesting is the very low start to the year with the extent cross over in early July, compared to the "record low" of the time.

I know, scratched record, but as this year evolves it is so much like a replay with post 2012 ice conditions, rather than post 2005 ice conditions.

I'm also very close to what Neven believes; which is that MYI is going to be hosed all year. Which I believe will lead to some pretty spectacular events next year.

[Sarat]

Hey all I would like to ask a question about the CICE ice concentration. I looked at June 20 data from 2012 until 2016, see below.

Not only the ice overall looks less concentrated than in any previous year, similar to 2013, there is a large balding section in the arctic basin (But unlike 2013 there is also a hole in Beaufort).

https://drive.google.com/file/d/0B2CAXmrYbSibaHlIeU1qa1pzb2M/view?usp=sharing

Mean while the wind patterns have consistently either spread the ice or pushed it out to export.

Even though above compactness measures show the ice equivalent to previous years the attached image visually looks like the pack is much less concentrated than in any year before. Is there something I am missing?

[Sarat]

Sitting here thinking about the issue I started answering my own question:

Compactness, as I understand it, disregards sea ice extent.

For example: If we look at two 10 km^2 areas of sea one is covered in a solid 10 km^2 sheet of ice and another has 1 km^2 solid floe both would have compactness value of 1, yet we cannot conclude that sea ice conditions in the two areas are are similar.

[Susan Anderson]

Whether it is this year or next, or even the next five years, it appears the sum of conditions is degraded multi-year ice, increased underwater temperatures, lots of smoke and pollution from wildfires, and who knows what else. Because of the deeply dishonest nature of opposition efforts to undermine both information and collection of information, we all "hope" for something to be a wakeup call. But in our hearts we also give huge sighs of relief when things are not so bad in the immediate present.

Moving on, I just saw this. The NYTimes provides 5 or 10 free views a month, and I had never heard of "watermelon snow" before. So partly just to share and partly curious if anyone knows anything about this:
http://www.nytimes.com/2016/06/23/science/watermelon-snow-global-warming.html
"Watermelon Snow: Not Edible but Important for Climate Change"

This would be more about glacial ice than far north ice, I'd guess, but it is disturbing.

[Neven]

I like the idea of using MASIE as the area measure for compactness.

MASIE would be the extent measure (hence the SIE in MASIE).

Assuming these have no ice they would not be included in SIE or SIA.

Everything that looks like water, be it open water or melt ponds, is included in SIA. For SIE it would have to be 85% water or more in a grid cell, and the total cover is deemed 0 km2. However if there's 15% ice or more, the grid cell is considered to be completely covered with ice.

Again, this is the primary reason sea ice extent exists as an alternative calculation to sea ice area: to reduce the impact of melt ponds.

Even though above compactness measures show the ice equivalent to previous years the attached image visually looks like the pack is much less concentrated than in any year before. Is there something I am missing?

Taras, compactness tells us something about how much water the satellites are seeing, a combination of open water/leads and melt ponds.

If, as you say, the ice pack looks quite dispersed, meaning there is a considerable amount of open water between floes, but compactness is not lower than in other years, this - in theory - means that there is relatively less melt ponding than in previous years.

The state of the ice in 2016 is not good at all, and with albedo feedbacks, the Arctic is right now much more sensitive to weather than it has ever been, so if even an average summer gets us to 3.8, a bit of melt-inducing weather will easily get us much lower.

I agree, Rob. I just state my views as of this moment. They can change within a week. I don't think the last word about this melting season has been said.

Whether it is this year or next, or even the next five years, it appears the sum of conditions is degraded multi-year ice, increased underwater temperatures, lots of smoke and pollution from wildfires, and who knows what else. Because of the deeply dishonest nature of opposition efforts to undermine both information and collection of information, we all "hope" for something to be a wakeup call.

Well said, Susan. Whether there's a record melting season or not, it's the long-term process that is the real - and worrying - story here. Although it was nice to have two rebound years after 2012, this year and last year are a clear continuation of the trend. If things stay the way they are or get worse even, it's just a matter of time before a less benign combination of conditions from May to August will force everyone to hit the snooze button again.

[Philip]

And MASIE just dropped over 270,000 km2 between day 172 and 173. The game is ON!

[Neven]

Yeah, I saw that. Made CAMAS go up more than 0.5%. :-)

[wayne]

Not surprising at all, given any compaction would tumble down the numbers + last ice core measurement at 82N was very warm perhaps warmest at same date. I've observed Greenland sea ice huge areas vanish along with everywhere else too bad Cryosphere Today data is mush. The main pack has already shattered, heat gained from open water especially now a days will prove further disastrous.

[D_C_S]

Susan Anderson: I've seen that algae in the mountains of SW Canada.

[Rob Dekker]

Interesting what the effect of this storm had been for the numbers :

- MASIE "extent" dropped 270 k
- Wipneus CT "area" dropped 143 k
- Wipneus AMSR2 "extent" dropped 83 k
- Wipneus AMSR2 "area" dropped 153 k

So it may be that CAMAS increased, but Wipneus' concentration graph dropped.

[Rob Dekker]

Also, there does not seem to be any physical reason why MASIE's "extent" would drop as a result of this storm. After all, a "low" over the Arctic typically would increase "extent" because of ice dispersion.

This low was situated over the central CAB, too far away from the "extent" boundary, so "extent" should not be affected much.
For example, Wipneus' "extent" drop was caused mostly by the Hudson and Baffin Bay.

So it is likely that MASIE's 200+ extent drop has more to do with their subjective way of estimating ice in the Arctic than with the effect of this (mild) storm.

[Philip]

MASIE data has extent drops in most of the peripheral seas and when you go look at the University of Hamburg map there is visible extent drop in each of those areas.

[John Christensen]

Agreed Rob; extent is going down quickly in the peripheral seas, but not in the CAB, where temps are held back by the low.

It will be very interesting to see if PIOMAS follows DMI, where we are still seeing very restrained volume decline:

http://polarportal.dk/en/havisen-i-arktis/nbsp/sea-ice-extent/

[Nick Naylor]

Compactness is currently at a record low, if you use the largest grid size possible- i.e., equal to the entire Arctic.
In that case, compactness = Area of Arctic - Ice Covered Area.
The difference of course is that smaller cells give a higher weight to open water/melt ponds in proximity to the ice.

[DavidR]

Assuming these have no ice they would not be included in SIE or SIA".

Everything that looks like water, be it open water or melt ponds, is included in SIA.

Surely if a grid cell has no ice it is not considered in SIA. So polynyas that cover a complete cell would not be counted in either SIA or SIE. This means that open water within the pack covering a complete measurement cell is not part of the compactness equation but should be.

Simple example 3 * 3 cell grid. Centre grid is empty other 8 cells are 100% full. SIA/SIE gives a figure of 100% But actual compactness is more like 88%. In an area like Beaufort with large areas of open water the compactness figure could well be artifically high.

[Neven]

I see what you mean now, David. Interesting idea, but difficult to assess. Also: What we perceive as large patches of open water on true-colour satellite images, often contain small ice floes that passive microwave sensors or the stuff used for operational analyses do pick up.

[Sam]

Wow.

I am ever more dubious of all of the ice thickness models. Thick ice never used to shatter. I doubt that it does now.

Yet across the vast expanse of the Arctic sheet we see extensive shattering nearly everywhere, and often what better resembles icebergs of ice surrounding by a 'glue' of low quality ice.

The ice sheet now looks very much less like an ice sheet and very much more like a new car windshield dropped off the back of a truck.

Sam

[Werther]

I agree, Sam.
Today day 175 I see little of the mesh-shaped grid leads/floes I once considered to be 'safe pack'.

[jdallen_wa]

Ice Bridge this year showed that there is a fair amount of older ice that's relatively thick - especially hard up against the Canadian Arctic.

However, it's far from consistent, and there's lots of ice they examined which is far thinner.

It's playing out everywhere; the only areas I've seen recently which resemble the old "Mesh Pack" are to the north of the Lincoln Sea, and even those are not especially secure.

I'm rather concerned.

[Rob Dekker]

Wipneus at the forum just posted the latest AMSR area and extent numbers :

Extent: -88.2 (-582k vs 2015, -430k vs 2014, -1012k vs 2013, -172k vs 2012)
Area: -64.6 (-503k vs 2015, -315k vs 2014, -869k vs 2013, -320k vs 2012)

This shows that 2016 is still firmly in the lead, both for "area" as well as "extent". It shows that the DIFFERENCE between extent and area (a good indicator of the amount of melting ponds and leads) is still larger now than in 2012. Which simply suggests that melting potential is larger now than in 2012, and 2016 will thus probably continue to drop faster than other years.

[D_C_S]

Rob Dekker: How does it compare to 2006? 2006 was record lowest in extent for this time of year according to NSIDC.

[D_C_S]

CORRECTION: How does it compare to 2010? 2010 was record lowest in extent for this time of year according to NSIDC.

[John Christensen]

"2016 will thus probably continue to drop faster than other years."

Rob, 2012 extent has dropped faster than 2016 if you compare from June 1st, May 1st or from spring extent max, so what is your reference period?

Given the weather forecast, I will bet you £10 (They are really cheap today) that 2012 will loose more extent in the next 14 days than this year, starting today.

[Neven]

Be careful, John. The forecast keeps moving more and more towards high pressure over the American side of the Arctic. If that moves slightly more to the CAB, 2016 will at least follow regular decrease rates of the past few years, which means it will stay low.

[DavidR]

D_C_S CORRECTION: How does it compare to 2010? 2010 was record lowest in extent for this time of year according to NSIDC.
2016 has been lower than 2010 for more than 90 days. This may not be true in a few days as 2010 is going through a period of rapid decline.

[DavidR]

John Christenson Given the weather forecast, I will bet you £10 (They are really cheap today) that 2012 will loose more extent in the next 14 days than this year, starting today.

Over the last 10 years 2012 has had the fourth biggest drop in extent over the next 14 days.

2007 and 2013 dropped approximately 400K km^2 more. The average is barely greater than 2012. What odds are you offering for 2016 dropping less than 2012?

[D]

The weather for the next 10 days will be cool in the central Arctic but warm in the Kara sea and the Canadian archipelago. This will help preserve the central ice pack but will continue to melt the periphery. Both the GFS and ECMWF agree on the general pattern of cool temperatures and low pressure near the pole.

There have been major shifts in the SST patterns in the NH ocean basins. The cool pool in the Atlantic has faded as warmth has pushed northwards into the sub Arctic seas. This will set up the Arctic ocean for an influx of warm salty Atlantic water over the next 5 years. The PDO shift in the Pacific to warmth on the coast of Alaska also favors warmer Pacific water entering the Arctic.

So what we are seeing is a mixed blessing. The central pack of sea ice is getting a reprieve but heat is building up on all sides of the central Arctic.

It will be very interesting to see how much cold fresh Arctic water flows out through the Canadian passages this summer. The Beaufort high acts as a huge reservoir of fresh water when it is strong then the water drains out when the pressure goes down. I haven't seen much discussion of the effects of this cycle which is years long on the sea ice but I'm sure it has effects. I will be watching the Canadian passages closely over the next 2 months.

-FishOutofWater otherwise known as George.

[John Christensen]

"Be careful, John. The forecast keeps moving more and more towards high pressure over the American side of the Arctic"

Agreed, predicting future is a gamble, but the 2012 extent saw a sharp drop starting 2-3 days from now, so we would need very favorable conditions to keep up with that.

[John Christensen]

"Over the last 10 years 2012 has had the fourth biggest drop in extent over the next 14 days.

2007 and 2013 dropped approximately 400K km^2 more. The average is barely greater than 2012. What odds are you offering for 2016 dropping less than 2012?"

The next 2-3 weeks include the steepest decline in extent of the melting season, as we both have the sun near maximum and heat having accumulated, often resulting in 15-20% of ice extent being lost in the last week of June and first week of July, based on today's date.
So we should expect days of steep decline..

And yes, I could have selected 2007 or 2013 (which would have been justified from Rob's comment), but they both start higher, so I felt it being more fair to select 2012, which is comparable to this year from a current extent perspective.

Given the AO forecast ( http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index_ensm.shtml )
while there will be areas of high pressure we should have overall dominance of low pressure areas, which given the already low extent should allow us to fare better than 2012.

Odds: I would say about 70% chance of 2016 faring better than 2012 for the next 14 days, given the difference in weather/forecast.

[wayne]

Ingen, nein , niet, no,oxi

The next few days North Pole will get hit by sun blast of its highest altitude for days. The perimeter of the main pack has always been bombarded with more sun from less cloud cover. Wait a bit and by the way, the models have problems with calculating surface temperatures accurately over sea ice along with alas now extinct mass buoys live data thermistors having water over them when sunny.

[Tom Zupancic]

Just a short note. I remain skeptical that recent precedents for sea ice conditioning are a sine qua non for significant Arctic Sea Ice melt. Rather, I prefer the hypothesis, based on the premise that it takes heat to melt ice, that there are alternative mechanisms that can result in substantial sea ice melting. I especially like this hypothesis when it appears that initial conditions this year are fundamentally different.

[Rob Dekker]

I probably should have worded that better, but the point is that the expression "extent minus area" is a very good indicator of the amount of melting ponds and lead and open water right next to the ice.
That is a very good indicator of short term melting potential.

And since "extent minus area" is right now at par or even larger than 2012, everything else considered equal, 2016 will follow the 2012 melting curve, if not outperform it.

[John Christensen]

NP Rob, it could also be argued that due to northward movement of the jet stream caused by positive AO, remaining ice of peripheral seas would be under increased stress..

Let's see what happens

[Rob Dekker]

OK John, yes, if that is true, it would only add to the 2016 advantage.
But I gotta tell you that I've not seen any scientific paper that links the AO to Arctic sea ice decline.

[Colorado Bob]

2016 Eastern Arctic ice melt weeks ahead of normal: Canadian Ice Service

Most of the ice on Frobisher Bay should be melted out by early July, says a forecaster with the Canadian Ice Service, as this year's melt in the Eastern Arctic is weeks ahead of schedule.

"The ice on the Northern Baffin Bay opened up earlier in May, maybe four or five weeks earlier than normal," said Jason Ross, a ice forecaster with the Canadian Ice Service.

"Elsewhere in the Arctic — Hudson Bay, Davis Strait and Labrador area — ice melted one to two weeks ahead of normal at this time."

Link

[Colorado Bob]

UK-funded ice breaker in 'elite' Arctic tourism row

Starting in Alaska, the 32-day voyage will see the 1,700 passengers and crew travel 1,500km across the top of Canada, ultimately ending in New York.

Berths on the 14-deck luxury liner are not cheap, starting at around $20,000 per person and running up to $120,000 for a deluxe stateroom.

While the route is accessible to ships, it is not ice-free and the company behind the voyage has chartered an ice breaker, RRS Ernest Shackleton, from the British Antarctic Survey.

Link

[Colorado Bob]

Siberian larch forests are still linked to the ice age
Press release from the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research
June 24, 2016 - 8:35am - By The Arctic Journal

A new AWI study shows that the flora of the Northern Russian permafrost lags behind the climate often by several thousand years

A look into the past indicates: The colder the ice age was, the longer the vegetation needed to adapt afterwards to the new climate of the warmer period. "In analogy to these results, this means: Due to the fact that the most recent ice age, about 20,000 years ago, was extremely cold, the permafrost spread over a large area, and forced deep rooted trees such as pines and spruces far to the south. The shallow-rooted Siberian larch trees - which only require a summer thawing of the permafrost soils of 20 to 30 centimetres - were able to survive in protected areas in the region," explained Ulrike Herzschuh.

The larch forest however, with its dense carpet of roots protects the ice underneath from thawing. "We have observed many times in regions where the larch forest was cut down, that the permafrost melted faster than in other forested areas," according to the AWI researcher.

[Rob Dekker]

Guys, the "ice concentration" metric (or more accurately "extent minus area") is only ONE variable that sets the trend for ice loss, or melting momentum.
Just plain "ice area" is another one : regression analysis shows clearly that in June, if the Arctic has low "area", that this amplifies melt down to September. Which makes sense : if there is less ice in June, there is more open (dark) ocean, which amplifies albedo feedback.
And the third main variable is "land snow cover".
This one (especially in June) correlates strongly with the amount of ice that will melt out until September.
Which make physical sense again, since snow-free lands absorb a lot of heat, which warms the winds over the land and thus warms the winds that will blow over the ice.

All three variables are currently close to 'record' level, which suggests that 2016 will be going low. But it may require a early August GAC to break the record, as happened in 2012.

[navegante]

I wonder if there is a better way to assess land snow cover anomaly than just by looking at monthly indicators. From the snow cover maps it is clear that practically there is no land snow left at high latitudes since two weeks ago, which is three or more weeks earlier than climatology. This is much time more to accumulate heat that will be later transferred to the Arctic by weather systems.
Yet the final June anomaly will look small since climatology will have catched up and will tell a wrong story.

[wayne]

Navegante,

Please check EOSDIS photos for lands featuring lots of snow....

https://worldview.earthdata.nasa.gov/?p=arctic&l=VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,Reference_Labels(hidden),Reference_Features(hidden),Coastlines&t=2016-06-26&v=-1904071.111111111,-1126912,-234951.111111111,-382464

[John Christensen]

Rob, you said:

" I've not seen any scientific paper that links the AO to Arctic sea ice decline"

You should read this:

The Summer Cyclone Maximum over the Central Arctic Ocean
Mark C. Serreze and Andrew P. Barrett, 2008, Journal of Climate

Which states:

"Variability in the strength of the cyclone pattern can be broadly linked to the phase of the summer northern annular mode" - This is the AO.

And this:

Dramatic interannual changes of perennial Arctic sea ice linked to abnormal summer storm activity
James A. Screen, Ian Simmonds and Kevin Keay, 2011, Journal of Geophysical Research

Which states:

"In particular, fewer cyclones over the central Arctic Ocean during the months of May, June, and July appear to favor a low sea ice area at the end of the melt season. Years with large losses of sea ice are characterized by abnormal cyclone distributions and tracks: they lack the normal maximum in cyclone activity over the central Arctic Ocean, and cyclones that track from Eurasia into the central Arctic are largely absent."

The NH polar jet is typically placed near 60N, but with positive AO the polar jet can move into the range of 60-70N, with temperatures normally being somewhat lower on the northern side of the polar jet compared to south of the jet stream.

If the polar jet moves north of the Hudson Strait, Foxe Basin, or Ungava Bay, temperatures in these areas will increase, accelerating the local sea ice melt.

Therefore, while positive AO generally is causing higher than normal Sept sea ice extent, there could be in May-June higher than normal melting activity in areas south of the polar jet.

In 2013, ice extent dropped significantly in the last 7-10 days of June, possibly related to high temperatures in southerly Arctic areas.

See the "Second storm" 2013 entry for some of those temperature examples in July 2013, and where the general opinion on the thread was still not sold on the concept that the storm/low would indeed be beneficial to the overall sea ice cover. Luckily, by July 2013, the sea ice was largely gone in areas impacted by higher temperatures..

[John Christensen]

Nice graphic showing the NH polar jet 'following the sun' - moving north in summer and south in winter:

http://www.classzone.com/books/earth_science/terc/content/investigations/es1908/es1908page04.cfm

[Bill Fothergill]

"...NH polar jet 'following the sun' - moving north in summer and south in winter..."

Some similarities with the behaviour of the ITCZ as the planet changes from boreal to austral summer there John.

[wayne]

http://eh2r.blogspot.ca/2016/06/despite-contrarian-winds-beaufort-gyre.html

Despite winds not conducive to compaction, the Beaufort Gyre turned clockwise throughout June, this is an amazing feature making some meteorologist scratch their heads. Only explainable by months of Gyre anticyclonic wind circulation just prior during March, April and through a good chunk of May.

[Robert S]

Wayne: If you review the CAA area shown in the EOSDIS image you linked to over a number of days you will see that most of the "snow" was in fact cloud cover. There's not much snow left there.

[wayne]

Robert, Nope, look carefully, compare Boothia Peninsula to Somerset Island just to the North. Also look at:

https://www.weather.gc.ca/data/analysis/352_100.gif

The snow over Somerset is confirmed. There was a great deal of snowfall over some parts of the CAA over winter just past.

[John Christensen]

wayne, you wrote on June 13th:

"But by no means gone for good. In fact I expected it, with especially the opening of CAA coast, a High should settle off Gyre centre in particular near the Pole."

And you mentioned this was already in the forecast.

Your point was that the low was not a 'normal' low, but rather a short-lived low caused by the numerous leads and that once the water vapor had evaporated a high near the Pole would appear.

How is your forecast holding up two weeks later?

It seems like this did not happen,

[Rob Dekker]

Wayne said

Despite winds not conducive to compaction, the Beaufort Gyre turned clockwise throughout June, this is an amazing feature making some meteorologist scratch their heads.

I'm not a meteorologist, but it made me scratch my head. Especially with the lows over the Arctic we have seen all through June.

The only explanation I can give is that if you plot the surface air pressure over many months (specifically Feb through May) on NCEP/NCAR,
http://www.esrl.noaa.gov/psd/data/composites/day/
then you will find that there was a sustained high positioned over the Beaufort Gyre, and a low over Alaska, that would have set the Gyre current in motion (and opened up the Beaufort early this year).

So it seems that the Beaufort Gyre current has a longer "memory" than most think...

[Cato Uticensis]

Still following the evolution of synoptic configuration on the Arctic... Well, both GFS and ECMWF show persistence of low-pressure systems for the next 7-10 days. In line with the paper cited by John, the low pressures keep originating from Asia, especially central Siberia, and then move to the Central Arctic Ocean, where they tend to persist and deepen. In particular, it looks like low pressures will tend to persist on Central Arctic, Laptev and ESS, leaving Beaufort and Canadian Archipelago more exposed to warmer S/SW winds originated by the combination of LP systems on the Gulf of Alaska and HP on the Canadian archipelago. As this pattern has been in place for several weeks already, I tend to believe these forecasts have a decent degree of predictability, even in the long term. Conditions conductive to melting in the Beaufort and early opening of NW Passages, then. And favourable to ice preservation on Laptev, ESS and CA. Overall, lots of clouds and associated precipitations. I leave the implications of this high level synoptic analysis to Neven as I will be eagerly waiting for the next updates!

[John Christensen]

Agreed, Cato, but let me add that also Greenland - after an early start to the melting season by late April - is seeing higher than average cloudiness and precipitation combined with average temperatures in June.

This results in accumulated surface mass balance (SMB) currently being significantly above 2012 and also above the 1990-2013 mean:

http://polarportal.dk/en/groenlands-indlandsis/nbsp/isens-overflade/

[John Christensen]

Yes, also the AO index forecast is showing no significant change over the next 7 days (Has 89.9% correlation with observations):

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.sprd2.gif

[wayne]

John,

"It seems like this did not happen",

The cloud burst happened, this is not related to the Cyclones hugging newly open water. The Anticyclones have indeed tried to settle and form but the Cyclones keep interrupting, look at ECMWF latest forecast where we can see a High or ridge forming near the Pole 5 out of 11 times , but it is pestered by small or larger Cyclones, wait a bit when temperature differentials will become greater by the warming in the open water zones. Let's see if there is anything else left of the pack capable of cooling things, so far the weaker Anticyclones or High pressure ridges vicinity North Pole have revealed a badly broken pack, more so than I anticipated. It is possible that we are witnessing the continuance of a different dynamical weather situation which is related to state of sea ice, much rater than the impossibly vague -not dedicated to the Arctic- AO index designed for Mid North America weather forecasts.

Rob

Indeed there is "memory" in the Gyre as proven by my GIF display of NASA EOSDIS excellent data base:

http://eh2r.blogspot.ca/2016/06/despite-contrarian-winds-beaufort-gyre.html

And it seems impossibly stubborn. But remember the under water sea ice ridging is probably greater than the surface, and of course the density of sea water is much greater than air.

[wayne]

leið til að fara Norse!

Near North Pole current Ice condition, between a rock frozen ice and a cloudy cooler place.

http://eh2r.blogspot.ca/2016/06/near-north-pole-current-ice-condition.html

as the title says, this year brings out our knowledge gained especially by 2013 melt. Insolation is key now, and the sun has less trouble to do its thing in 2016. But sea ice is never linear, never easy
and always interesting.

[Robert S]

Wayne: You're quite right about Somerset's snow retention. I was looking farther north at places like Ellef Ringnes. To me the great story of 2016 may not be minimum extent, but rather a massive loss of the multi-year ice north of the CAA. Already quite a lot of that ice is in the Beaufort, where it has been being hammered for weeks by heat drawn from the land. There have also been pretty consistent heat flows off the lowlands of North Greenland, Ellesmere, Axel Heiberg, extending for hundreds of kilometers to the north. That's the flip side of the lows - cloud cover, yes, but also heat being drawn into the arctic.

If this year marks a substantial further loss of multi-year ice, I think that represents a dynamic phase change in the arctic ice which will be as, or more significant than an extent record. Young ice in places like the Laptev has a completely different albedo at this point in the season than big multi-year floes, due to the extensive fragmentation. If that is the future across the arctic, things will accelerate.

[D_C_S]

Regarding the statement in the blog article "That is why sea ice area will always be lower than sea ice extent", I suppose that if there were nothing left of the arctic sea ice except for 10% of the area in a few grid boxes then the extent would be 0 but the area would be greater than 0. There are also scenarios in which some grid boxes would have more than 15% ice coverage and in which extent would be less than area, if I understand the definitions of "area" and "extent" correctly.

[Cato Uticensis]

Just an example of what could be boiling in the pot... http://www.wetterzentrale.de/pics/Rhavn1681.gif and these would be the temperatures.. http://www.wetterzentrale.de/pics/Rhavn1683.gif 7 days is a long time, but it's nice to see anyway, and just a variation on the current theme of low pressure systems in the Arctic...

[Neven]

D_C_S, I believe that sea ice concentration below 15% is also considered 0% for sea ice area. So, under no circumstance can area be greater than extent. :-)

[John Christensen]

I had not pulled this yet, thanks for sharing Cato!

Amazing how the situation has stabilized; it seems like moisture will keep pushing up across Greenland from Denmark Strait, continuing above-normal precipitation and accumulation there.

[D_C_S]

Neven: In that case, the definition of "area" is explained poorly on NSIDC's terminology page.

[iceBunny]

@D_C_S: It's poorly explained on the terminology page .. https://nsidc.org/cryosphere/seaice/data/terminology.html .. where no mention of a threshold is given in the text and the example of extent/area/concentration mentions a threshold for extent (a hypothetical 30% for the sake of illustration) but not for area, and gives a value for area when the concentration is under the extent threshold.

However, on the FAQ page .. http://nsidc.org/arcticseaicenews/faq/#area_extent .. they explain it more fully and give an example that discounts area of below-threshold cells.

Area takes the percentages of sea ice within data cells and adds them up to report how much of the Arctic is covered by ice; area typically uses a threshold of 15%. So in the same example, with three 25 km x 25 km (16 miles x 16 miles) grid cells of 16% ice, 2% ice, and 90% ice, multiply the grid cell areas that are over the 15% threshold by the percent of sea ice in those grid cells, and add it up. You would have a total area of 662 square km (255.8 square miles).

[Chris Reynolds]

There is no expectation of a record this year using the late June Compactness indicator.
http://dosbat.blogspot.co.uk/2016/06/no-early-warning-of-2016-crash.html

[D_C_S]

For June 28, arctic sea ice extent in 2010 is less than arctic sea ice extent in 2016 according to NSIDC, at 9.596 Mm^2 and 9.625 Mm^2, respectively.

[Rob Dekker]

You mean that for the first time this melting season, 2016 is actually behind another year (2010).