Arctic Sea Ice

2011/2012 Winter Analysis

I'm starting this blog post off with a conclusion that was reached a while back already: sea ice on the Atlantic side of the Arctic looks vulnerable, sea ice on the Pacific side should be thicker.

Right, with that out of the way we can now look at various aspects of the 2011/2012 freezing season, and compare them to previous years, to be precise the previous freezing season of 2010/2011, and the freezing seasons leading up to and following that other record year: 2006/2007 and 2007/2008. Simply put: I'll be comparing 2007, 2008, 2011 and 2012 before their respective start of the melting season.

I'll try not to use too many words, but I'll be using a lot of images. Click on them images if you want a bigger version.

Ice age

I'll start with the AARI ice age maps. These images are for the end of April, and they look upside down, because it's from the perspective of the Russians who produced them:

SIE 2011 update 12: fumbling in the dark

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 15th 2011

It happens some times. Just when things get exciting one graph or other stops updating. For many weeks we had to go without the PIPS ice displacement map, which in my view is quite indispensable for short-term forecasts of extent decrease. But when IJIS stops reporting new data, things get really awkward. I mean, this whole SIE update business revolves around the IJIS extent data, right?

So I was fumbling through the dark when the IJIS data file froze up on us on the 11th. Was the extremely high rate of extent decrease continuing? Or was there a slump due to atmospheric patterns switching again? To be fair, I thought the latter was going on. That big high over the Arctic Basin was slowly moving towards the Alaskan coast, PIPS ice displacement arrows becamse a bit smaller, and Cryosphere Today sea ice area decrease was slowing down considerably, diminishing chances of a new global sea ice area anomaly record I alluded to in the previous SIE update.

So you can imagine my surprise when I just woke up this afternoon after a long night of work to see that 2011 has actually fended off 2007's attack in the form of a 4 day consecutive series of century breaks. In fact, 2011 responded by noting 4 century breaks in a row itself. Of the last 14 days 10 had century breaks reported.

We have to invent a new word, as amazing, awesome, fantastic, gigantic, enormous and grandiose no longer cut it. Okay, I'm doing a bit of the hyperbole stuff here, but how long can this keep up?

Sea ice extent (SIE)

Here's the current IJIS SIE graph:

So 2011 is still tracking 2007 and actually keeping a slim stroke of white between them. The difference with other years and earlier contenders such as 2006 and 2010 is increasing very fast at the moment. Except for 2009 most years are going to start slowing down, although 2007 is maintaining a formidable rate of extent decrease all throughout the month.

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

SIE 2011 update 11: the heat is on

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 9th 2011

Last week I wrote in the conclusion of SIE 2011 update 10:

I think we are going to see above average melting the coming week, perhaps even some century breaks.

This is exactly what has come about. Not that it was hard to predict, as everything was pointing to a big high-pressure area stabilizing over the central Arctic. In fact, I even was a bit too cautious/cowardly. The first 8 days of July saw 5 century breaks, of which 3 made it into the top 10 of biggest daily extent decreases (h/t Lord Soth).

As the sun keeps burning hot and long, its rays reaching much of the ice in the Arctic Basin, 2011 is tracking 2007 and 2009, the only years having an average daily extent decrease of over 100,000 square km in the first 8 days of July. And although that high-pressure guaranteed a substantial drop in extent, there was and still is plenty to learn and observe.

Of course, dominating high-pressure areas are a prerequisite for mega-melt, but how much do details in distribution matter? The Dipole Anomaly requires a high-pressure area over the Canadian Archipelago, extending to Greenland. For the Beaufort Gyre to gyre the high-pressure should be ideally over the Beaufort Sea (hence the name I guess). But this current high-pressure area is very large and over the centre of the Arctic Basin, almost directly over the North Pole, which prohibits strong ice export through Fram Strait, to name a thing. Still the extent decreases fast.

What will the effect of all this insolation in the middle of the ice pack be as we enter the second halftime of the melting season? And of course the million dollar question: will 2011 keep tracking 2007? How long is this high going to dominate?

Sea ice extent (SIE)

Here's the current IJIS SIE graph:

2011 decided to forge ahead, leaving 2010 in the dust and even increasing the lead over 2007. This is quite amazing as 2007 had a stunning run of century breaks in this first part of July. I guess I don't have to explain that this means 2011 is currently leading in the race. 2010 is finished for the rest of the month and will fall back quickly. The same goes for 2006, albeit to a lesser extent. 2009 will start to put up a fight towards the end of the month. But right now it's between 2011 and mighty 2007.

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

PIPS is back: more info

Just a few days ago I was crying with joy that PIPS had finally come back online again. The ice displacement maps are indispensable to my amateur analysis of what's going on in the Arctic as we speak and so it was great to see it come back on-line. But it gets even better.

Peter Ellis informed us in the comments of the previous PIPS blog post that there was an announcement on the PIPS website:

Since late April/early May 2011, PIPS 2.0 has developed an unrealistic opening in the North Pole region. On 22 May 2011, PIPS 2.0 stopped running because of a numerical instability. Since that time, we have been carefully trying to diagnose this problem (checking for anomalous atmospheric forcing, initial fields, boundary conditions, assimilated satellite ice fields, etc). During this process, the system's ocean model time step was reduced and the system is currently running again. The unobserved opening near the North Pole is still present and can be seen in the ice concentration and ice thickness fields. PLEASE USE THESE FIELDS WITH CAUTION! We have subsequently filled in the period from October 2010 to present with the hindcast using the reduced ocean model time step. Because PIPS 2.0 is a legacy system and will soon be replaced with a new ice nowcast/forecast system (see below), little additional effort will be expended to keep it running.

I think it's fantastic that the people from the Naval Research Laboratory put up this explanation of what has happened. And the announcement that the Polar Ice Prediction System (PIPS 2.0) is now a legacy system, is quite stunning. But not nearly as stunning as the news that it is going to be replaced with a new forecast system:

PIPS is back!

Short, but important news:

I have sent these guys at least 5 mails. Maybe the last one I sent out to the webmaster yesterday helped. Either way, thank you, Naval Research Laboratory!

Ice thickness models 2

As promised I'm returning to the sea ice thickness models I wrote about two weeks ago, highlighting some of the current differences between PIPS, PIOMAS and TOPAZ. The satellite that will give us a definitive answer on ice thickness and volume, CryoSat-2, is currently being calibrated with the help of surveys by ESA and NASA. It will take some more time before definite data will be made publicly available, so in the meantime we'll continue looking at what sea ice thickness models have told us so far.

PIPS 2.0 2004-2011

PIPS 2.0 (Polar Ice Prediction System) has an excellent archive, so I have retrieved all the ice thickness images from the period 2004-2011 and put them side by side (click for a larger image):

Ice thickness models

One of the most intruiging and elusive aspects of Arctic sea ice is its overall thickness, and by implication the total volume of sea ice. The bigger the volume, the longer it will take for the Arctic Ocean to become effectively ice-free in summer. Unfortunately, despite many different kinds of data, no one can tell for sure what the current status is, except that volume has decreased significantly over the past decades.

Satellites could provide more definite answers, but we are currently in a gap between ICESat and CryoSat-2. ESA and NASA are doing a fascinating job in the Arctic gathering data which will be used to calibrate the latter as we speak. In the meantime we fill the time by speculating, and a big part of that speculation is fueled by ice thickness models.

The best known models in Arctic sea ice amateur circles are PIPS 2.0 (Polar Ice Prediction System), PIOMAS (Pan-Arctic Ice-Ocean Modeling and Assimilation System) and TOPAZ (Towards an Operational Prediction system for the North Atlantic European coastal Zones). Although model output is not as good an approximation of reality as actual data - to put it mildly - it is still interesting to look at.