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 23rd 2011
As I concluded in the last SIE update sea ice extent decrease has slowed down a bit, but despite some similarity to 2010, it's the differences that stand out.
Most of you will remember how 2010 was going down hard, when all of a sudden atmospheric conditions in the Arctic altered radically. Low-pressure areas moved in and kept almost all of the Arctic in a deadlock for a month and a half, resulting in one of the lowest extent decrease rates for July in the IJIS dataset (starting 2002) and some spectacular satellite images of a massively diverging ice pack.
This past week low-pressure areas have moved in as well, and extent decrease has slowed down, but this year's low isn't as low as last year's low (and will stay not so low for a while to come). Extent decrease has slowed down, but area decrease has been picking up, which has had consequences for CAPIE as well (more below). And last, but most certainly not least, the distribution of low-pressure and high-pressure areas is different from last year.
What we have been seeing the past couple of days is the so-called Dipole Anomaly causing ice to be blown away from the Siberian coast and transported towards Fram Strait (I have started an animation to keep an eye on progress over there) by the Transpolar Drift Stream. If this keeps up, a lot of ice will be blown through Fram Strait and melt out at lower latitudes, AND that huge warm water polynya in the Laptev Sea is going to eat its way through the first year ice towards the North Pole. These effects could seriously come into play towards the end of the melting season.
The key question is, of course: will it keep up? Is it one step back, and then two steps forward? Or will we see a repeat of 2010?
Sea ice extent (SIE)
Here's the current IJIS SIE graph:
2011 has just passed the 7 million square km mark, one day earlier than 2007, but despite this we can clearly see 2011 bending off towards 2007, as there were a few low extent decrease days this past week (one day of 30K being particularly low). At the same time 2007 is landing a few punches with a small series of century breaks. It still has 5 days of relatively high daily extent decreases coming up, so it remains to be seen if 2011 will remain in the lead (probably not).
The current difference between 2011 and the other years is as follows:
- 2005: -782K (-83,709)
- 2006: -723K (-70,025)
- 2007: -101K (-98,608)
- 2008: -1024K (-81,068)
- 2009: -717K (-92,127)
- 2010: -593K (-62,601)
Between brackets is the average daily extent rate for the month of July. 2011's average daily extent rate for July is currently -99,197 square kilometers, which is 15K lower than last week. Here's the average other years had after the first 22 days of July:
- 2005: -86,058
- 2006: -73,899
- 2007: -107,536
- 2008: -81,527
- 2009: -96,783
- 2010: -59,261
- 2011: -99,197
Sea ice area (SIA)
I was doubting a bit this past week if 2011 really was record material, as SIA (and by consequence CAPIE too) was lagging behind. But in the past couple of days area decrease has accelerated quite significantly. This has caused the trend on the Cryosphere Today SIA anomaly graph to shoot down to over -1.7 million square km:
Because of the increase in ice transport towards Fram Strait, the SIA anomaly in the Greenland Sea has shot up (it was relatively high to begin with). Something to keep an eye on. In the Arctic Basin SIA has gone down some more, although extent has gone up a tad. In the Canadian Archipelago both SIA and SIE are going down hard, probably having to do with the ice in the Northwest Passage and between the islands of the Archipelago starting to crack up all over the place. Sea ice area in the East Siberian Sea is still dropping very, very fast.
Cryosphere Today area per IJIS extent (CAPIE)
With area going down much faster than extent,our CAPIE percentage has taken a nosedive and is currently lowest in the 2005-2011 period:
Sea Level Pressure
As I've shown in the last SIE update, the high that was stuck over the Beaufort Sea weakened in strength and moved towards the Canadian Archipelago, while low-pressure areas were starting to form off the Siberian coast. Here's an animation of SLP images from the DMI Centre for Ocean and Ice of the past week:
A very weak high on the North American side of the Arctic combined with a big low on the other side (very big today) is pushing the ice out towards Fram Strait, as can be seen on the PIPS ice displacement forecast maps:
In the past two days the arrows aren't pointing as clearly towards Fram Strait, probably due to that very big low. This could mean that the Dipole Anomaly is already losing its effect, unless a high over the Canadian Archipelago reforms.
So what can we expect the coming few days? According to the NOAA Ensemble Mean AO forecasts the Arctic Oscillation will continue to remain fairly neutral the coming 7-14 days, perhaps even going slightly negative after August 1st:
And here's the ECMWF forecast for the coming 5 days:
The weak highs over the Canadian Archipelago are forecasted to be pushed out completely by lows. This would mean the Dipole Anomaly was short-lived and we won't be seeing a large increase of ice transport towards Fram Strait in the coming week. But as the AO remains fairly neutral, all it needs is the right distribution of highs and lows for transport to pick up again.
Update conclusion
I'm not expecting extent decrease to radically stall like it did last year, but I'm not seeing any century breaks coming about either the coming 5-7 days. I was hoping we'd see more of that fast ice transport toward Fram Strait to see what it would do to the SIE and SIA numbers, but the highs aren't in the right place. The low off the Siberian coast is pretty strong right now, but is forecasted to weaken in the coming days. It'll be interesting to see what happens.
At the moment 2011 is neither fish nor flesh. It could very well be losing its 100K lead to 2007 in the coming week.
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TIPS - Other blog posts and news articles concerning the Arctic and its ice:
I have updated the Northwest Passage animation.
Patrick Lockerby has written an update to his Arctic Ice July 2011 analysis.
Gareth Renowden has done an update on the current situation in the Arctic: Wet, wet, wet
AGW poet Horatio Algeranon has written a cover to a Steam song: Na Na Hey Hey Kiss the Sea-Ice Goodbye
Robert Grumbine is continuing his series of blog posts on Arctic sea ice: Sea Ice Wagers and Reconsidering Forecasts and Wagers
Those colours on the CT sea ice concentration map do not necessarily correspond with melt ponds, Philiponfire. I think clouds have something to with that as well, fooling the sensor. If those colours would stay put for a couple of days, there might be something going on, but that are continuously appearing and disappearing from one day to the next.
Indeed, Lord Soth. The AO might go negative, but that's mainly because of a few big highs moving on from Scandinavia and staying in place above Svalbard. With the (big) low on the other side, we now get ice transport form Greenland/CA towards the Laptev Sea.
This is already apparent on the DMI SLP map:
Those isobars between the big yellow and blue blots show the wind direction and thus ice displacement at the moment. If this keeps up for a few days we will start to see holes in the interior of the ice pack, I think. ECMWF is forecasting things to saty as they are now, with a big low and a big high opposite each other, but exactly in the wrong spots for big extent decreases.
On the other hand, I always say that the switching in weather patterns is causing the slowdowns. If things do stay like this for a week or so, we might see an interesting rate of decrease nevertheless. Those waters in the Laptev Sea aren't exactly cool.
But let's not write too much, otherwise I won't have enough material for the next SIE update. :-)
Posted by: Neven | July 28, 2011 at 19:03
It can clearly be seen on the PIPS ice displacement map as well:
The ice is transported away from Fram Strait, towards Siberia.
Fascinating...
Posted by: Neven | July 28, 2011 at 19:08
NSIDC News -- 14 July 2011
AMSR-E Sea Ice Drift Data Now Available from NSIDC
Posted by: Artful Dodger | July 28, 2011 at 19:40
A useful website for visualizing the extended forecast for the Northern Hemisphere is this NOAA site:
http://wxmaps.org/pix/hemi.fcst.html
I like it because you can click on "All Times" for 500 mb Geopotential Hieght Vorticity and get a single page where you simply scroll down to see the forecast for the whole week.
There is a lot of additional information for each day that you can see by selecting "All Fields" for an individual time point.
Posted by: Tzupancic1 | July 28, 2011 at 19:48
Thanks for those two links, guys.
Posted by: Neven | July 28, 2011 at 20:58
Thanks for those links, Lodger.
I seem to recall something else as well. Sea water keeps getting denser as it cools toward freezing (at nearly 2 kelvins below the freezing temperature of pure water). So the coldest water keeps sinking until there is enough of a stack of very cold water to slow the sinking enough for the upper water to freeze before it sinks.
On the other hand, if the Arctic surface waters became very fresh for some reason, say a collapsing ice sheet, the Arctic sea might freeze as fresh water does, leading to a much greater extent and a severe winter. I hope the chance of this is below .1.
Posted by: Pete Dunkelberg | July 28, 2011 at 23:11
where id the data located for Breman.
Posted by: Chris Biscan | July 28, 2011 at 23:30
Chris, the Uni Bremen data are not public yet, though I hope they will become so. Their long-term calibration is not complete. The data at present are said to be valid for day-to-day but not historical comparisons, hence the current UB website's approach of just showing the recent years graphically.
One interesting aspect of the UB time series is that it extends back to 1972 (but with that caveat about not being calibrated). Another is that they have estimates for southern hemisphere ice extent as well.
I try to respect my promise not to publish their data, and the historical cautions, while still occasionally posting a cryptic note here when I see something interesting happen.
Posted by: L. Hamilton | July 28, 2011 at 23:59
Hi Pete,
This is what I wrote about salinity on September 11, 2010.
Unless salinity goes below 30 psu, the Arctic does not freeze like a fresh-water lake.
Posted by: Artful Dodger | July 29, 2011 at 00:15
aha! Lodger that's the one. Thanks again.
Meanwhile back on the ice, this looks like a good time to study pure melting in place. What is known about the import of heat by ocean currents?
Posted by: Pete Dunkelberg | July 29, 2011 at 02:09
Well, there's SHEBA and NAME... and there's this little "Arctic Ocean Heat inflows" chart by Wieslaw Maslowski:
Yes, all those little TW's are terawatts. (a terawatt is equal to one trillion (10^12) watts.)
Posted by: Artful Dodger | July 29, 2011 at 03:45
How much do clouds effect the ice sensors
Posted by: Chris Biscan | July 29, 2011 at 05:55
As Rob Dekker commented above,
"Now, since 2011 has the same ice area at 2007, it seems reasonable to assume that the enhanced melt will occur again (ice albedo). However, if the transpolar drift does not crank up, then 2011 will have a hard time keeping track of the Aug/Sept decline of 2007.
On the other hand, if PIOMAS is even remotely correct, then ice volume (ice thickness) in 2011 is already more than 2.5 10^3 km3 smaller than it was in 2007, which makes the 2007 Aug/Sept loss of 0.8 10^3 km3 look insignificant.
I think 2011 is a test of various hypotheses and we are observing the data rolling off in real time.
Posted by: Tzupancic1 | July 29, 2011 at 05:55
"On the other hand, if PIOMAS is even remotely correct..."
Reardless of the weather.
This is the question that currently fascinates me. If the Arctic Sea Ice volume is so reduced, what are the implications?
Posted by: Tzupancic1 | July 29, 2011 at 06:03
Implications of reduced volume?
First, that comparisons based on area and extent are fundamentally misleading. In other words, be careful comparing 2007 to 2011.
Second, that there has been no meaningful recovery of arctic sea ice.
Posted by: Andrew Xnn | July 29, 2011 at 06:17
60K prelim on Jaxa.
Posted by: Chris Biscan | July 29, 2011 at 09:42
Chris wrote : How much do clouds effect the ice sensors ?
Not sure how much clouds affect the sensors, but clouds very much affect the melt rate. During July, the sun in the Arctic is still brutal. Clear sky melt rate for insolation alone can easily be 3-5 cm/day for already battered ice. But if the sun is blocked by clouds (having high albedo) ice melt rates will reduce significantly, down to a standstill for thick clouds.
Interestingly enough, at the end of July (July 28 if my calculations are right), the radiative balance of the atmosphere starts to turn negative. That means the atmosphere will loose more heat (to space) than it absorbs from solar irradiance. That means it will cool down. After that, at the surface, cloud cover and sensible heat transfer (warm air blowing in from lower lattitudes) will determine the melt rate and ultimately the point where melting ponds start to freeze over and melting halts.
So clouds (and weather in general) are very important in the Arctic.
If I have a chance, I'll post some results of the radiative balance and melt rate calculations for different surface and weather conditions, which will confirm that conclusion. Credit to Wipneus and others who helped me find the right tools.
Posted by: Rob Dekker | July 29, 2011 at 10:05
Rob, if you want your efforts to be turned into a blog post, you know where to find me.
Posted by: Neven | July 29, 2011 at 10:07
Thanks Neven. After all the great info I obtained from you and so many excellent posters here, I know that I owe you a blog post with what I've learned. My main problem is time... Don't have enough of it. And some tools to make graphs and pictures for a blog post.
Posted by: Rob Dekker | July 29, 2011 at 10:41
Disturbing or may I say "Welcome to the USSA"
http://www.guardian.co.uk/world/2011/jul/28/arctic-scientist-polar-bear-oil
Posted by: Espen | July 29, 2011 at 12:21
I have turned that Guardian article in a blog post.
Tell me about it, Rob. In fact, I feel a bit guilty for not following your lead into this. Things like insolation and bottom/top melt rates are very interesting. Maybe we'll get around to it towards the end of the melting season.
Posted by: Neven | July 29, 2011 at 12:51
The "New Polynia" has returned... just noted it in the CT Arctic image North-East tip off Greenland
http://arctic.atmos.uiuc.edu/cryosphere/NEWIMAGES/arctic.seaice.color.000.png
Cstch it while you can.
Posted by: Seke Rob | July 29, 2011 at 20:00
It looks like a lead is opening up in Arctic Web Cam 1.
Posted by: michael sweet | July 29, 2011 at 22:48
it looks to me as though there is now a North West channel open for small craft as of Modis day 29th july.
I am referring to a route through Prince Regent inlet, Bellot strait, Franklin strait, Rae strait, Simpson strait and Coronation gulf.
nothing more than ice cubes on that route now.
Posted by: Philiponfire | July 29, 2011 at 23:56
Jaxa and UB have diverged themselves some.
So far the extent and area have slowed to a crawl.
I can't expect this to last given it is only July 30th but this a good sign.
Posted by: Chris Biscan | July 30, 2011 at 18:02
I strongly suspect August 2011 will hold a dramatic surprise. Vast amounts of warmer than usual water with a little nudge from a negatively trending AO Index, and the race between 2007 and 2011 will be far more interesting than would appear as of July 30.
Posted by: R. Gates | July 30, 2011 at 19:19
I agree that there is still a lot of potential for extent decrease, but things will have to start changing soon now if 2011 wants to remain record material.
I'm writing a new SIE update tonight and will elaborate some more.
Posted by: Neven | July 30, 2011 at 19:22
I don't get why Jaxa and UB seem to be pretty far apart at this moment.
Posted by: Chris Biscan | July 30, 2011 at 22:38
If you look at JAXA and UB graphs side by side they never match exactly so there is no reason for them to be identical now.
Posted by: Philiponfire | July 31, 2011 at 00:26
Things do look dismal at first glance, however we must remember that we are looking at extent, not area or volume.
Think of the arctic circle as a slice of toast. Think of the volume of ice as the peanut butter. Think of weather conditions as the knife.
The knife has been very effective in spreading the peanut butter over the toast in a nice thin layer.
The only problem with this analogy is that the peanut butter does not melt, like the thin ice.
When looking at the extent chart, one thing that stood out about 2007, was not the depth of the curve but the width. The ice melted early and recovered late. Right now 2011 looks alot more like 2007, more than any other year.
Right now 2011 is within 2% of 2007 for extent, practically tied for area, and way ahead for volume lost.
2007 not only had the lowest extent, but also known for extreme compaction.
August, 2007 showed 4 century breaks at the start of the month, but after the first week, it took 23 days to lose a million km, as it hit the wall on available compaction, and had to depend on in situ melt for it extent losses.
The big question is, can 2011 beat 2007, without the level of compaction that 2007 has.
Posted by: Lord Soth | July 31, 2011 at 12:32
I fully agree that 167k or 2.5% more extent than 2007 is only one measure and not all that significant. We should keep area and volume in mind as well as extent.
We have had an area century break putting area 44k below 2007 and below the gompertz fit of 4.383 for the next release. I suggest area is more important than extent.
Volume is the only measure that is way below 2007 but it is difficult to know how to rate the importance of this to this year minimum relative to area and extent measures.
So of extent, area and volume, 2 to 1 measures say 2011 is leading.
We can, however, also say is that these sizes of lead or lag have in the past been relatively unimportant compared to weather.
Maybe at some stage volume will become much more important than it has in the past but there doesn't yet seem much reason to think that will happen this year.
Posted by: crandles | July 31, 2011 at 16:32
even with the slow melt days.
the ice has a large area that is about to compact/melt out.
look at those large areas of low low concentration.
Posted by: Chris Biscan | July 31, 2011 at 16:40