Arctic Sea Ice

PIOMAS October 2016

Another month has passed and so here is the updated Arctic sea ice volume graph as calculated by the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) at the Polar Science Center:

The minimum was reached in September for modelled sea ice volume as well, and 2016 came in third, just behind 2011 (99 km3 difference) and well behind 2012 (728 km3). In the meantime, despite the early date of minimum and the rapid increase in extent that followed it, 2016 caught up with 2011 a bit and they are practically at a par at the end of September. 2016 clearly belongs in the 2010-2012 group and is much lower than the years preceding that period and the rebound years that followed 2012.

Here's how the differences with previous years have evolved from last month:

And here are the numbers and bar graph that show how this year's total melt stacked up against other years. It is 5th highest, bearing in mind that maximum sea ice volume was second lowest on record back in April after a mild winter, with total accumulation being third lowest in the 2006-2016 record:

Wipneus' version of the PIOMAS volume graph also shows how this year's trend line almost dropped as low as 2011, and has been on a par ever since:

ASI 2015 update 7: to compact or not to compact

During the melting season I'm writing (bi-)weekly updates on the current situation with regards to Arctic sea ice (ASI). Central to these updates are the daily Cryosphere Today sea ice area (SIA) and IJIS sea ice extent (SIE) numbers, which I compare to data from the 2005-2014 period (NSIDC has a good explanation of sea ice extent and area in their FAQ). I also look at other things like regional sea ice area, compactness, temperature and weather forecasts, anything of particular interest.

The animation on the right consists of NSIDC
sea ice concentration maps, one for each ASI update.

Check out the Arctic Sea Ice Graphs website (ASIG)
for daily updated graphs, maps, live webcam images and
the Arctic Sea Ice Forum (ASIF) for detailed discussions.

September 1st 2015

Look at the sea ice concentration animation at the top right. Notice how the final frame suddenly is whiter than the preceding frame? That's a sign that we have entered the final phase of the melting season, when temperatures drop and melt ponds within the ice pack freeze over again. Sea ice concentration goes up, and the NSIDC SIC map becomes whiter.

But the Pacific side of the Arctic is still bluish. During the past two weeks the disintegration of that part of the ice pack has continued, spurred on by a late cyclone that further stressed the region (see special blog post on the matter) and increased the area that consists of a mix of ice floes and open water. The compaction potential of this region will probably decide where this melting season will end up on the various sea ice area and extent graphs.

And this end result still holds interest, because - somewhat surprisingly - the 2015 melting season could still achieve a top 3 minimum. Surprising, because the melting season started out with more volume, more multi-year ice, saw little and late preconditioning during May and June, and - despite a killer July - there has been relatively little transport and compaction this year.

With melting momentum mostly out of the picture now, it all comes down to compaction.

Sea ice area (SIA)

Here's the latest Cryosphere Today SIA chart, to which I've added preliminary data as calculated by Wipneus:

ASI 2015 update 5: late momentum

During the melting season I'm writing (bi-)weekly updates on the current situation with regards to Arctic sea ice (ASI). Central to these updates are the daily Cryosphere Today sea ice area (SIA) and IJIS sea ice extent (SIE) numbers, which I compare to data from the 2005-2014 period (NSIDC has a good explanation of sea ice extent and area in their FAQ). I also look at other things like regional sea ice area, compactness, temperature and weather forecasts, anything of particular interest.

The animation on the right consists of NSIDC
sea ice concentration maps, one for each ASI update.

Check out the Arctic Sea Ice Graphs website (ASIG)
for daily updated graphs, maps, live webcam images and
the Arctic Sea Ice Forum (ASIF) for detailed discussions.

July 30th 2015

My apologies for being a week late with this update. In my defence: things have been remarkably stable in the past three weeks, or all month really, both weather conditions and trend lines on graphs. To make up, here's a guest blog I've written, that was posted by John Abraham on the Guardian website today.

The article describes the melting season so far, starting out with more sea ice volume than previous years, because of the rebound in volume after the 2012 mega-record melting season. This year the ice pack underwent little preconditioning during May and June, perhaps slightly more than 2013 and 2014, but much less than big melt years such as 2007 and 2012.

This order of play led to the early conclusion that 2015 wouldn't break any records, and could very well end up near the previous two rebound years. However, subsequent weather conditions during all of July have broadened the range of possibilities (see the previous ASI update). I'll be going into the details in the July analysis that will be posted in 10 days or so, but I can tell you that July 2015 was exceptionally sunny and warm.

And that brings us to this melting season's main theme: Will the rebound remain intact, or will it be reversed, and perhaps even wiped out?

Let's first have a look at what has happened in these past 3 weeks.

Sea ice area (SIA)

Here's the latest Cryosphere Today SIA chart, to which I've added preliminary data as calculated by Wipneus:

ASI 2015 update 4: massive heat

During the melting season I'm writing (bi-)weekly updates on the current situation with regards to Arctic sea ice (ASI). Central to these updates are the daily Cryosphere Today sea ice area (SIA) and IJIS sea ice extent (SIE) numbers, which I compare to data from the 2005-2014 period (NSIDC has a good explanation of sea ice extent and area in their FAQ). I also look at other things like regional sea ice area, compactness, temperature and weather forecasts, anything of particular interest.

The animation on the right consists of NSIDC
sea ice concentration maps, one for each ASI update.

Check out the Arctic Sea Ice Graphs website (ASIG)
for daily updated graphs, maps, live webcam images and
the Arctic Sea Ice Forum (ASIF) for detailed discussions.

July 7th 2015

I wanted to wait for the latest PIOMAS update and do another melt pond analysis for June, but given the current circumstances and the forecast I've decided to squeeze this ASI update in first.

As we've seen in previous ASI updates this melting season hasn't had a flying start, but it hasn't been as slow as 2013 and 2014 either. With extent going low real fast, but area lagging behind, the compactness numbers indicated little melt pond formation and no divergence to speak of. Melt ponds - and to a lesser extent openings within the ice pack - are important because they lower the ice pack's albedo and soak up a lot of sunlight, preconditioning the ice for further melting. This melting momentum, as I call it, can play a decisive role in the latter half of the melting season, trumping weather conditions.

Of course, weather still plays a very significant role in the final outcome of a melting season. This year hasn't seen any substantial preconditioning and is more similar to rebound years 2013 and 2014 than record years 2012, 2007 and 2011. In fact, this year has been very much like last year, in the sense that there is hardly any movement. Very little ice is transported through Fram Strait to the North Atlantic ice graveyard, and there is no compaction or divergence to speak of because of a lack of strong winds. Most of the extent/area decrease is caused by so-called in situ melting, or melting on the spot.

However, there is one big difference compared to last year and that's heat. Despite a very cold start, there have been several outbreaks of warm air over the ice, slowly but radically shifting the balance between extent and area data. The impact is felt on the surface of the ice pack, but doesn't translate directly into a decrease. Not yet. In theory, it should percolate through after a while, especially if the heat persists. And right now the Arctic sea ice pack is undergoing a massive heat wave which shows no signs of letting up.

More on what has happened and what is going to happen below.

Sea ice area (SIA)

Here's the latest Cryosphere Today SIA chart, to which I've added preliminary data as calculated by Wipneus:

Big drops have been alternating with small upticks, keeping the trend line near the upper half of the pack, but below that of 2013 and 2014.

ASI 2015 update 3: what's it going to be?

During the melting season I'm writing (bi-)weekly updates on the current situation with regards to Arctic sea ice (ASI). Central to these updates are the daily Cryosphere Today sea ice area (SIA) and IJIS sea ice extent (SIE) numbers, which I compare to data from the 2005-2014 period (NSIDC has a good explanation of sea ice extent and area in their FAQ). I also look at other things like regional sea ice area, compactness, temperature and weather forecasts, anything of particular interest.

The animation on the right consists of NSIDC
sea ice concentration maps, one for each ASI update.

Check out the Arctic Sea Ice Graphs website (ASIG)
for daily updated graphs, maps, live webcam images and
the Arctic Sea Ice Forum (ASIF) for detailed discussions.

June 21st 2015

Today is the day of summer solstice, when the Sun reaches its highest point as seen from the North Pole, beating down 24 hours per day on the sea ice below (when not blocked by clouds). The period preceding and following this event is very important for how the melting season plays out, as it is during this time that large parts of the Arctic sea ice pack are preconditioned through melt ponds.

This preconditioning in turn influences melting momentum. A lot of momentum almost guarantees high melt rates, whereas little momentum does the opposite, depending on weather conditions during July and August as well, of course. Last week I wrote a blog post in which I tried to assess the amount of melt ponding through May, by comparing this year to previous years.

The first half of May was extremely cold, with the second half of May showing almost the exact opposite. Still, indications were that relatively few melt ponds have shown up during May and the first half of June. This is now changing, as can be seen on the animation at the upper right hand corner of this blog post, where sea ice concentration is showing a very large blue patch of lower concentration on the Pacific side of the Arctic. That's because weather conditions conducive to melting shifted from the American side to the Siberian side of the Arctic, as was forecast two weeks ago.

Below an assessment of what's been happening in the past two weeks, and what is going to happen next week.

Sea ice area (SIA)

Here's the latest Cryosphere Today SIA chart, to which I've added preliminary data as calculated by Wipneus:

CT SIA recorded a huge 340K drop in one day. The last time a triple century break was recorded was in 2008. This brings the 2015 trend line right in the middle of the highest and lowest trend line in the 2006-2015 period.

2014/2015 Winter analysis

If you want to know where you're going, it helps to know where you're coming from. This also goes for Arctic sea ice. Even though the long-term trend is down, it's difficult to tell what will happen in any given melting season. Two things can help us get an idea: initial sea ice state and subsequent weather conditions. This post is about how the sea ice has fared throughout the freezing season and what shape it was in last month when sea ice growth slowly came to a grinding halt and winter started to make way for spring.

For that I'm going to compare the 2014/2015 freezing season with those of the preceding three winters, just like I did last year. That way we can see how the past winter compares to the winters preceding the 2012 record smashing melt and the two rebound years following it. If you want to compare some of the images below with other freezing seasons, you can dig through the 2011/2012 and 2012/2013 winter analyses. And click on the images if you want to have a closer look.

Ice age

We kick off with the AARI ice age maps for the end of April that show the amount of multi-year ice (MYI) in the Arctic (brown colour):

Last year's genetically modified rat has been replaced by a woolly mammoth (I'm sorry, I can't help but seeing animals in these maps), but the amount looks about the same. What is interesting this year is that the MYI looks a lot more fragmented on the Pacific side of the Arctic, with some young ice (pink) and even open water in the Chukchi Sea.

This has everything to do with a cracking event that took place a couple of weeks ago. It wasn't as spectacular as the cracking event of February/March 2013, but it was still quite big, and more interestingly, it took place at the very end of the freezing season. We have to wait and see if there's any consequence for the melting in this region. On the one hand there's a lot of first-year ice (FYI) between the MYI floes which could melt out early. On the other hand heat might be released to the atmosphere, cooling the water below the ice, making it more resistant to melting.

Either way, it's visible on different maps, such as the ASCAT radar images. Here's a comparison for day 109 (April 19th):

ASI 2014 update 9: minimum around the corner

During the melting season I'm writing (bi-)weekly updates on the current situation with regards to Arctic sea ice (ASI). Central to these updates are the daily Cryosphere Today sea ice area (SIA) and IJIS sea ice extent (SIE) numbers, which I compare to data from the 2005-2013 period (NSIDC has a good explanation of sea ice extent and area in their FAQ). I also look at other things like regional sea ice area, compactness, temperature and weather forecasts, anything of particular interest.

The animation on the right consists of NSIDC
sea ice concentration maps, one for each ASI update.

Check out the Arctic Sea Ice Graphs website (ASIG)
for daily updated graphs, maps, live webcam images and
the Arctic Sea Ice Forum (ASIF) for detailed discussions.

September 14th 2014

The 2014 melting season is about to end. The end result is very similar to that of last year, despite large differences between both melting seasons. Last year the Arctic was dominated by persistent cyclones, keeping things cold and cloudy. This year there were more bouts of sunny weather, but it seems little heat was imported from lower latitudes. A lack of strong pressure gradients also caused relatively little movement and export, clearly to be seen on the Atlantic side of the Arctic, where in the last couple of years (even last year, see here) an onslaught had taken place.

At the same time, on the Pacific side of the Arctic, the ice that had been strengthened due to last year's rebound, managed to hold out through much of the melting season, although the late momentum seems to be sustaining the melting season now (together with weather, of course). Large areas of very thin ice and milky wisps in the Beaufort, Chukchi and Eastern Siberian Seas are disappearing, keeping many a trend line dropping on sea ice graphs.

But most of this weak ice will be saved by the bell, like we saw in 2010 and 2011, and the 2014 melting season will basically end up at the same level as last year and 2009. If not today, then later this week.

Sea ice area (SIA)

The season may already have turned the corner on the Cryosphere Today graph, after having dipped 71K below last year's minimum on the same date as last year:

Third storm

Are we getting used to this? After the persistent cyclone in May and June, and the spiffy, but short-lived cyclone of two weeks ago, the Arctic is visited by yet another intense storm that goes below 980 hPa. In fact, according to Environment Canada it is currently at 976 hPa, which is lower than the lowest pressure of the previous storm (click for a larger version):

Do also note the high pressure over the Beaufort Sea, Canadian Archipelago and Greenland. Yesterday's DMI SLP map also shows the storm developing:

According to the ECMWF weather forecast the storm will stay intense today and tomorrow, and then wind down again, albeit more slowly than the last one, and accompanied by more high pressure on the American side of the Arctic (click for a larger version):