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:
- 2005: -1101K
- 2006: -1409K
- 2007: +127K
- 2008: -189K
- 2009: -789K
- 2010: -446K
If 2011 loses as much sea ice extent as...
- 2005 did after this date it will bottom out at 4.21 million square km
- 2006 did after this date it will bottom out at 4.37 million square km
- 2007 did after this date it will bottom out at 4.38 million square km
- 2008 did after this date it will bottom out at 4.51 million square km
- 2009 did after this date it will bottom out at 4.46 million square km
- 2010 did after this date it will bottom out at 4.37 million square km
The 2007 IJIS minimum extent was 4.25 million square km. 2008 was 4.71 million square km. We are currently at 4.53 million square km.
Sea ice area (SIA)
As said, the Cryosphere Today sea ice area record has been broken. Nuff said.
It has slightly gone up again, but is still lowest, and so the Cryosphere Today SIA anomaly graph is still showing the largest anomaly ever recorded for this date:
As we can see on the Regional Graphs page, the Arctic Basin and Canadian Archipelago are relatively flatlining at the moment. Everything seems to depend now on the slush puppie ice left in the East Siberian Sea that still has some more room to go down, as has the Greenland Sea graph.
Cryosphere Today area per IJIS extent (CAPIE)
The 2011 trend line has gone up a bit, but is still behind 2007 by quite a few percentage points. Although the total amount of ice seems to continue to go down without much problems, some serious compacting action is probably still needed to break the records on the last remaining extent graphs.
Sea Level Pressure (SLP)
As usual, we first have a look at the animation of SLP images from the DMI Centre for Ocean and Ice to see what happened in the past week:
In the bottom of the animation we see a huge low pressure area moving in. I didn't believe it at first, but that really was what remained of hurricane Irene, which had battered the US East Coast a couple of days earlier. The effect on the Arctic was some increased movement towards Fram Strait, but at the same the detachment of the ice pack from Severnaya Zemlya. Another smaller low probably pushed some ice into the melted-out channels of the Canadian Archipelago, but due to cloudiness it was hard to confirm on the satellite images.
As the week wore on, the ECMWF weather forecast model was starting to change its tune. It was showing large highs claiming their place on the North American side of the Arctic. The 5 day (and up) forecasts was showing what could only be described as the perfect Dipole Anomaly set-up, which would undoubtedly have extended the melting season and broken every record that isn't unbroken yet.
But, as so often happens, the forecast for the coming 5 days has changed again:
As we can see, there are some highs trying to pry their way in over the Canadian Archipelago. Unfortunately that big low is pushed out a tad too far to get that Transpolar Drift Stream going and the Beaufort Gyre is nowhere to be seen either. The AO index has been positive for the past two weeks (meaning lows are dominating the Arctic) and their forecast ensemble is not showing much change for the coming two weeks. So, if a high-pressure system is going to find a niche, it better be at the right spot.
This is something to be watched on a daily basis. It all depends now on what's exactly happening in the East Siberian Sea and Greenland Sea. That's where all the potential is.
I don't want to sound like a broken record, but some records have been broken this week. Whether all will be broken still depends on the weather, although the combination of thin ice and warm waters has been more than compensating the lack of ice compacting weather.
The prospects for a record IJIS SIE minimum extent have improved somewhat, but the fat lady is still humming. Not singing, but humming:
TIPS - Other blog posts and news articles concerning the Arctic and its ice: