Arctic Sea Ice

SIE 2011 update 21: post mortem

During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good explanation of what sea ice extent is in their FAQ. I also look at other things like sea ice area, concentration, volume, temperature and weather forecasts, anything that can be of particular interest. Check out the Arctic sea ice graphs webpage for daily updated graphs, maps and live webcam images.

September 24th 2011

This is the last SIE update for this melting season, which ended about two weeks ago (feels like an eternity). I have basically said everything I think needed saying with regards to the minimum, so I won't repeat myself here. Just like last year I've had a very educative experience, and I'd like to thank the 'old' crew and newcomers for all the info and inspiring speculation they've been bringing to this little corner of the Internet. That's what's making this blog worthwhile in my opinion.

As always I'll start with the IJIS sea ice extent graph:

We can see the upswing when the melting season ended abruptly on September 9th. After a few days the increase slowed down and it's now more or less tracking 2008. The interesting thing to do is to try and find out what the mechanism is behind the uptick and the subsequent slowdown in increase.

It has obviously everything to do with the weather at this stage of the transition phase between melting/compacting and spreading/freezing, so I suggest we first have a look at this animation of images from the DMI Centre for Ocean and Ice that I've saved:

Final score: 2011 vs 2007

Now that I've called the minimum, it's time to have a look at the differences between the two years with the lowest minimums in all data sets. This post will be a potpourri of different factors.

If we look at the six most important data sets - which IMHO are IJIS extent, NSIDC extent, Cryosphere Today area, Uni Bremen extent, DMI extent and PIOMAS volume - we see that this year a new record has been reached in three of them:

In the remaining three (NSIDC, IJIS and DMI extent) 2007 still holds the record low, but 2011 brushes past very closely and is firmly in second place:

If we compare the sea ice concentration maps from the University of Bremen we can see how close 2007 and 2011 match, despite differences in final shape:

SIE 2011 update 20: the fat lady is still humming

During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good explanation of what sea ice extent is in their FAQ. I also look at other things like sea ice area, concentration, volume, temperature and weather forecasts, anything that can be of particular interest. Check out the Arctic sea ice graphs webpage for daily updated graphs, maps and live webcam images.

September 10th 2011

The incredible has happened. In the past week the 2011 melting season has started to surpass record year 2007. First, the good people from the Polar Science Center informed us of the fact that their PIOMAS model is showing a new sea ice volume record. A day later a new all-time low on the Cryosphere Today sea ice area graph was reached. And two days after that the same thing happened on the University of Bremen sea ice extent chart.

In a sense this isn't so incredible, as we have been well aware of the fact that this could happen from the start of the melting season. But what does make it incredible, is that freak melting season 2007 is equaled and even surpassed. Four years ago, weather conditions that on average occur every 20 years or so, brought huge amounts of heat into the Arctic via air and water, flushed large amounts of ice through Fram and Nares Strait and - to top if off - compacted the ice pack so hard at the end of the melting season that the minimum extent was finally reached in the last week of September.

Up until mid-July this year's melting season resembled that of 2007, but after that things fell apart on the atmospheric front. The heat had been brought in alright, but the flushing through Nares (which opened late) and Fram was slow, and in these last weeks of the season there isn't much compaction to speak of, as the winds are too fickle to stay in place for a prolonged period.

Despite all this 2011 is right down there battling it out with 2007 on almost every graph. This is a sure sign that the ice is very weak and thin in large parts of the ice pack, which means that perfect weather conditions conducive to melting and compacting are no longer necessary to break records. The ice will melt out, regardless of what the weather does. That doesn't bode well for years to come.

We now wait and see if new minimums will be reached on the two popular extent graphs from IJIS and NSIDC. It all depends obviously on what date the minimum will be reached. In last week's SIE update I was pretty pessimistic on that score. This changed during the week, as weather forecast models were showing signs of a set-up that would extend the melting season and crush the ice pack in the process. But as nothing in the Arctic is a dead certainty (especially not the weather forecasts), things have changed again.

Sea ice extent (SIE)

Here's the current IJIS SIE graph:

In the past week SIE has been going down steadily, but slowly. 2007 had a few days of above average extent decrease and thus 2011 has still quite a few square kilometers to make up. The time to do that is next week when 2007 slows down enormously. It will take some extraordinary conditions, though not impossible. 2005 and 2010 had some really large decreases around that time.

The current difference between 2011 and the other years is as follows:

SIE 2011 update 19: the fat lady is humming

During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good explanation of what sea ice extent is in their FAQ. I also look at other things like sea ice area, concentration, volume, temperature and weather forecasts, anything that can be of particular interest. Check out the Arctic sea ice graphs webpage for daily updated graphs, maps and live webcam images.

September 3rd 2011

We are slowly approaching the end of the melting season. 2011 has secured a second spot on most area and extent graphs. The only question now is whether there's enough momentum left to break the 2007 record(s).

We have seen some signs this melting season that extent and area numbers aren't so dependent on weather conditions any more. In the past week for instance, we saw how a small and short-lived high-pressure area over the Beaufort Sea almost led to a century break and two more days of above average extent decrease.

In absence of a strong Beaufort Gyre and Transpolar Drift Stream we can only conclude this has to do with the weak or slush puppie ice at the Pacific side of the ice pack. It did quite a lot of melting in situ and who knows how well it would have compacted had weather patterns looked anything like 2007. Because, just like last year, they didn't. Around mid-July the weather turned bad for extent decrease, recovered somewhat after 3 weeks, but with hiccups. This kind of weather in the pre-2007 era would have inevitably led to a minimum extent above 5.5 million square km.

Still, there is one thing that can prevent weak, thin ice from completely melting out, and that's freezing temperatures and diverging winds. In other words, the end of the melting season. Last week I ended my introduction to SIE update 18 with the following remark:

Barring some really strong weather patterns that keep the ice in place and freeze the water over at the edges, we are in for a final phase of the melting season where everything is possible.

So what can we expect? More on that further below, but I think the fat lady could be humming a few bars. 

Sea ice extent (SIE)

Here's the current IJIS SIE graph:

2011 has halved 2007's lead yet again, but didn't manage to fully profit from 2007's slow extent decrease of the last couple of days. I think it's going to be very difficult to break the IJIS record minimum extent now, because 2007 had three weeks of extreme compaction in the final weeks of the melting season, leading to some very strong extent decrease days (for the time of year), and of course a very late date for the minimum extent. However, 2011 is about to edge past 2008's minimum extent in a day or so.

The current difference between 2011 and the other years is as follows:

SIE 2011 update 18: ten yard line

During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good explanation of what sea ice extent is in their FAQ. I also look at other things like sea ice area, concentration, volume, temperature and weather forecasts, anything that can be of particular interest. Check out the Arctic sea ice graphs webpage for daily updated graphs, maps and live webcam images.

August 27th 2011

We have an exciting week behind us. And that's putting it mildly.

In the last SIE update I referred several times to the unfulfilled potential the ice pack is showing this melting season, even making it the title of the update. A coupe of days later we saw some of that potential being put to use when a big cyclone ripped through the Beaufort and Chukchi regions, causing an unprecedented (I think) case of flash melting in a huge area of the ice pack. Normally you get a bit of ice melt/compaction everywhere at the edges of the ice pack, but this week we saw a massive amount of ice just disappearing from the radar one day to the next. Stunning stuff.

Of course, it is impossible for so much ice to disappear in just 24 hours, but the cyclone managed to disperse the floes, which probably got washed by water in the process, in such a way that concentration fell below the 15% threshold combined with some other factors (there has been much speculation regarding this matter in the Flash melting post). Some of the ice could show up again in the coming days if the winds push it together.

The cyclone was as short-lived as it was big, which means there still is a lot of untapped potential out there. The satellite images and sea ice concentration maps don't lie and show us how weak the ice is at the edges. We even see the water that has been warmed up to the brim in the Laptev Sea starting to eat its way into the ice pack, towards the North Pole.

As usual, weather patterns in these last 2-4 weeks of the melting season will determine the final outcome. But what makes this year so interesting is that this dominant influence is being superseded by the state of the ice. In other words, the ice determines how much influence weather patterns are allowed to have. This week's cyclone, for instance, would have actually made sea ice extent jump up only ten years ago because of its diverging power. But you can't diverge what you disintegrate.

Barring some really strong weather patterns that keep the ice in place and freeze the water over at the edges, we are in for a final phase of the melting season where everything is possible.

Sea ice extent (SIE)

Here's the current IJIS SIE graph:

IJIS extent is about to break through the 5 million square km barrier, for the fourth time in the satellite record, after 2007, 2008 and 2010. This year has managed to nibble off some more of 2007's lead (with the help of a very late century break due to the 'flash melting'), but a difference of 191K square km is still quite significant at this stage of the melting season. 2007 is having some very slow days at the end of the week, so maybe 2011 can get closer still. In the meantime, it seems to be fending off 2008's massive attack quite well, still leading by almost 300K square km.

The current difference between 2011 and the other years is as follows:

SIE 2011 update 17: unfulfilled potential

During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good explanation of what sea ice extent is in their FAQ. I also look at other things like sea ice area, concentration, volume, temperature and weather forecasts, anything that can be of particular interest. Check out the Arctic sea ice graphs webpage for daily updated graphs, maps and live webcam images.

August 20th 2011

Switching weather patterns slowed down the sea ice decrease, as they often do. I must admit I was expecting a bit more after the massive drop in sea ice extent of 127K (the second highest daily drop IJIS recorded during August) last week. I was also expecting CAPIE to go up again (after it hit a record low percentage on August 12th), but because extent would catch up, not because area would shoot up by more than 100K in two days.

On the other hand, despite adverse weather patterns, this year has managed to nibble away at 2007's lead and halved it in 10 days time. This of course says something about the state of the ice, which is so weak it melts anyhow or easily gets compacted in specific areas (see the latest animation). Perhaps not this year, but we are approaching a time when weather patterns will no longer be able to prevent extent and area numbers to drop through the floor.

To repeat what I wrote on August 9th: "If 2011 manages to get within 150K of 2007 by August 20th, the race is on again." I don't think this will become about, as the difference is 250K with only one day to go. It's now very probable that the 2007 minimum extent will remain the record. At the same time the combination of slush puppie ice and relatively high sea surface temperatures make it difficult to rule anything out, as we enter the final weeks of the melting season.

Nothing in the Arctic is a dead certainty.

Sea ice extent (SIE)

Here's the current IJIS SIE graph:

As said, 2007's lead has been almost halved from 470K to 251K from August 9th to 19th. Except for 2008 which had a very big extent decrease in August, 2011 has managed to increase its lead over other years. Barring a really early end to the melting season, this year is bound to end up somewhere in the top 3.

The current difference between 2011 and the other years is as follows:

SIE 2011 update 16: flash melting

During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good explanation of what sea ice extent is in their FAQ. I also look at other things like sea ice area, concentration, volume, temperature and weather forecasts, anything that can be of particular interest. Check out the Arctic sea ice graph webpage for daily updated graphs, maps and live webcam images.

August 13th 2011

I took my eyes off the ice for two days, which was a grave mistake. Just like life, the melting season goes slow, but lightning fast at the same time. No time for distraction. I've been catching up today, had an intense look and read to get that gut feeling back, and as always it is difficult to express how fascinating the Arctic and its ice are.

I had essentially ruled out a new record minimum extent last week, stating that 2011 would only have a chance left if by August 10th sea ice extent would be within 200K square km of 2007. Even though this didn't come about, I left the door ajar, as the weather seemed to be shaping up for increased declines. I'll quote myself from a comment on August 9th: "If 2011 manages to get within 150K of 2007 by August 20th, the race is on again."

I still stand behind that. At the same time must admit I had expected extent to go down a bit faster. Not that things were going slow for this time of year, but I'd (wishfully) thought we'd see a century break or two. There's still 7 days to go until August 20th, and the difference between 2007 and 2011 is somewhat smaller, but still significant. At the same time 2011 hasn't budged when it comes to sea ice area, and our CAPIE graph is signalling major divergence of the ice pack.

This divergence is taking place on the Pacific side of the Arctic and can be seen on sea ice concentration maps and on satellite images (through the many clouds). Where holes in the ice pack were the most striking feature of last year's melting season, I would say this year is increasingly characterized by a sea of slush puppy ice in the Beaufort and East Siberian Seas.

Greyish, brown, spread out like butter on warm toast. Despite high SSTs, high air temperature, battering winds, waves and sun, this rotten ice is still somehow managing to keep the extent from dropping through the floor. For how much longer, I wonder.

If 2011 is to set new records, it'll have to do so on this battlefield where the Arm of multiyear ice held out till the very end. That Arm is not there this year, or at least it's not as muscular. We'll see what the arm-wrestling brings this year.

Sea ice extent (SIE)

Here's the current IJIS SIE graph:

Not much has changed really since the last SIE update, except that - as I expected last week - the 6 million mark has been passed. 2011 has nibbled a bit at 2007's lead, but is still more than 400K behind. It has however maintained and even increased its lead over the other years. 2007's extent decrease is leveling off in the coming week, so perhaps 2011 can creep a little bit closer. Like I said, depending on the slush puppy and weather patterns (more on that below).

The current difference between 2011 and the other years is as follows:

SIE 2011 update 15: one step forward

During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good explanation of what sea ice extent is in their FAQ. I also look at other things like sea ice area, concentration, volume, temperature and weather forecasts, anything that can be of particular interest. Check out the Arctic sea ice graph webpage for daily updated graphs, maps and live webcam images.

August 6th 2011

We have seen about 3 steps back since weather patterns shifted in the Arctic about 3 weeks ago. But they have been shifting again, and this has now resulted in one step forward. It's quite a big step forward, as some extent decrease potential had been building up during the slowdown. In the meantime, area decrease hasn't really let up and 2011 is still leading the pack there. Needless to say, things are fascinating to watch.

It was only around mid-August that 2010 started to flip back again, so if this current transition sticks around for a while, the slowdown was half as long as last year's. Which explains why 2011 is still a contender, where 2010 had thrown in the towel by now.

It's not a done deal that 2011 will now cruise towards the finish and take the trophy, though. Those big highs I mentioned in the last SIE update have taken position. They are not ideally placed, but very big and pretty strong too. They will stay that way for the next couple of days, so this is bound to have an effect. But during the slowdown 2007 managed to take a big lead, at least when it comes to IJIS sea ice extent. If 2011 can manage the damage and nibble away at that lead we're in for a formidable finale. It won't be easy.

I stand by what I said in the previous SIE update: if by August 10th the difference between 2007 and 2011 is more than 200K, we can effectively rule out a new minimum extent record. August 10th is just a few days away, so I don't think the difference will be less than 200K, but if 2011 makes an extra effort, the extent decrease rate speeds up, and weather patterns more or less stay as they are, I'm willing to take back what I said.

Sea ice extent (SIE)

Here's the current IJIS SIE graph:

The gap between 2007 and 2011 can clearly be seen, but so is the downturn in the red trend line. IJIS reported a century break for yesterday's date, and almost a century break the day before. With the current weather patterns and the compaction potential I think we could be seeing 1 or 2 more century breaks in the coming week. This could be enough to start creeping towards 2007, which has ended its final century break series, or at the minimum stay well ahead of the others. Except for 2008 all other years have run out of century breaks.

The current difference between 2011 and the other years is as follows:

SIE 2011 update 14: two steps back, one step...

During the melting season I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2010. NSIDC has a good explanation of what sea ice extent is in their FAQ. I also look at other things like sea ice area, concentration, volume, temperature and weather forecasts, anything that can be of particular interest. Check out the Arctic sea ice graph webpage for daily updated graphs, maps and live webcam images.

July 31st 2011

In the last SIE update I mentioned some of the differences between this year's melting season and last year's. These differences, however, do not seem to make much of a difference when it comes to extent decrease.

The rate of extent decrease has been stalling big time ever since weather patterns started shifting two weeks ago, offseting the influence of insolation that has warmed up the water considerably through June and the first half of July.

Area decrease was quite significant for a while though, making this year's trend line on the CAPIE graph plunge precipitously, a sign that the ice pack has been spreading out quite a bit. Not to the level of last year when we saw 'holes' showing up in large areas of the interior of the ice pack, but we might start seeing those in the coming two weeks.

The big difference with last year is in my view that last year had been dealing with a very positive Arctic Oscillation around this time, whereas this year the AO was slightly positive for a while, but is now increasingly turning negative. Here's a blink comparison of the two years:

But the AO index only tells us one thing: whether hig-pressure areas or low-pressure areas are dominating the Arctic. It doesn't tell us anything about the distribution of those areas, which is of major importance for ice transport to lower latitudes.

High-pressure areas on the North American side of the Arctic - if they are stable and stay put for a while - will invariably lead to a higher extent decrease, especially if they combine with strong low-pressure areas on the Siberian side of the Arctic.

Whereas we have high-pressure areas moving into the Arctic for a couple of days now, they are on the wrong side, ie north of Novaya Zemlya and Scandinavia, and mirrored by a low-pressure area over the Beaufort Sea, which is reversing the circular direction of the Beaufort Gyre.

2010's slowdown came to an end mid-August, leading to a final sprint that secured a top 3 position. Whether this year the same will happen, remains to be seen. I personally believe 2011 still has a lot of untapped potential, but it will have to assert itself in the coming weeks, as the window for extent decrease is slowly, but inexorably starting to close.

Sea ice extent (SIE)

Here's the current IJIS SIE graph:

2007 has clearly taken over the lead, despite some slow days which were matched by even slower days this year (just 23K yesterday and today), and opens the first 9 days of August very strongly with 4 century breaks. If 2011 doesn't manage to keep up with that and the difference between the two years grows to over 200K, I think the chances of this year breaking the minimum extent record are minimal and we'll have to start focusing on the question whether 2011 can hold on to second place. It still has a comfortable lead over other years, but 2008 is about to go turbo.

The current difference between 2011 and the other years is as follows:

August SEARCH Outlook Contribution

Here is my next contribution:

Pan Arctic Outlook

Christopher Randles

Public outlook, statistical method

1.      Extent Projection  4.438 + (End of July CT area - 4.383) * 0.9176 m km^2

+/- 95% confidence interval of 0.8 m   

2.      Method – single linear, single non-linear regression

A gompertz fit of the NSIDC September extent figures is used as a starting point.

Linear regression is then used to predict the residual from the Gompertz fit using the residual of the end of July 2011 Cryosphere Today area number from a gompertz fit of end of July area numbers.

3.      Rationale

Several contributors have used multiple linear regression. This felt inadequate when there appears to be a curved shape that other contributors have used quadratic, exponential, logistic or gompertz fits to approximate.

For the July outlook I used both area and volume data to predict the residual. For this outlook, PIOMAS volume data does not appear to improve prediction of the residual significantly and has been dropped.