Arctic Sea Ice

Comparing

Last week, I opened a special thread over on the Arctic Sea Ice Forum to compare 2012 and 2019, because basically, that's what it comes down to at this point. In the thread, people post data, maps, graphs and satellite images to get an idea of how this year matches up with 2012. Towards the end of the month, I hope to use some of that material to provide a summary, before heading into the final phase of the melting season.

Today, one ASIF commenter called Comradez posted a YouTube video in which he compares 2012 and 2019 satellite images of one part of the Arctic (the intersection between the Beaufort Sea and Central Arctic Basin), which is exactly what I would hope to see when opening the thread. Here it is:

A couple of days ago, I saw this video on the broader implications of ice loss around the world. It's from one of my favourite alternative news channel called The Real News Network (highly recommended):

That's it for now. More to come towards the end of the month. We won't know whether the 2019 melting season will result in a new record low minimum, but we'll probably know whether it's still possible or not.

PIOMAS April 2019

Apologies for not posting an update last month (busy).

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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:

Look at the red line in the graph above. Do you see it essentially flatline towards the end of March? That's the primary cause for 2019 smashing the record for lowest March volume increase in the 2007-2019 period (and probably before that as well). The March average for that period was 1869 km3, the record was 1557 km3 (March 2015), and this year's March came in at 1339 km3. 2019 went from 7th to 4th place in the rankings, with 2011 just 89 km3 lower and a gap with leader 2017 that went down from 2279 km3 to 1834 km3.

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

Wipneus' version of the PIOMAS graph shows that 2019 still has some ways to go to catch up with 2017 (that went extremely low because of a horror winter, but luckily bounced up again during spring and early summer):

Beaufort final update

This isn't a final update as such, because I will certainly be mentioning events in the Beaufort Sea in upcoming ASI updates. But it is the last in a series of blog posts I have written (one, two and three) about this unprecedented event that started over 6 weeks ago and has led to a heavily cracked ice pack and a huge amount of open water on the American side of the Arctic.

The event has received some attention on other blogs and in the mainstream media. Just yesterday this image was posted on NASA's Visible Earth website, comparing this year to 2015 and 2014 (mind you, the Beaufort Sea opened up early last year as well):

The image is accompanied by a text, quoting Walt Meier:

“It really is quite remarkable,” noted Walter Meier, an ice specialist at NASA’s Goddard Space Flight Center. “There is always fracturing of the ice, but it seems to have become more prevalent and more widespread in recent years. This region used to be mostly multi-year ice, which is quite a bit thicker. Now, most of the Beaufort is seasonal, first-year ice. The thinner ice is weaker and more easily broken up by the winds.”

There are some links to other articles at the end of the Visible Earth article.

As I mentioned two weeks ago it looked as if that persistent high-pressure area was shifting away from the Beaufort, which would probably put "an (temporary) end to the massive cracking and ice movement". The animation below shows there has been some movement, but not as much as in prior weeks. Cloudiness makes it difficult to perceive, but if you focus on one of the two larger ice floes in the red circles, you can get an idea of the scale of movement/change:

Beaufort under relentless (high) pressure

When I wrote the Beaufort under early pressure blog post last month, I didn't quite expect this unprecedented pressure (timing and magnitude) to keep up for so long. High pressure areas tend to be short-lived in the Arctic, but this one was still going strong when the Beaufort quick update was published. Now, almost three weeks later, things still haven't completely calmed down, and this animation of satellite images showing weekly changes from March 30th to May 4th provides an astonishing sight:

Astonishing, mindblowing, frightening even. May is the month when melt ponds start to form on the ice, pools of water that lower the albedo and cause the ice to melt faster, leading to open water that absorbs solar radiation and warms up. The open water is already there in the Beaufort Sea. Look at all that open water!

No other year comes even close to it, as can be seen on the ASIG comparison of sea ice concentration maps, or on this sea ice extent graph (based on AMSR2 data, provided by Wipneus):

Jim Hunt provides this close-up view on the resources page of his Great White Con website (also be sure to read his latest blog post on early wave activity in all this open water):

Beaufort quick update

It's been a week since I announced that the ice in the Beaufort Sea was going to come under early pressure. Here's a quick update on what has happened so far, how the forecast played out, and what the short-term conditions for this part of the Arctic will be.

As expected, the Beaufort Gyre kicked into action, big time, with winds causing large cracks in the ice pack, moving it westwards and away from the Alaskan and Canadian coasts. The massive polynyas that are left behind, get partially covered with a thin veneer of ice.

Here's an animation showing the difference between LANCE-MODIS satellite images on the first of the month and two weeks later:

Quite impressive, isn't it? As if someone threw a giant brick into it.

Here's an animation showing all days between April 1st and 14th (the file is somewhat large, apologies if it loads slowly):

Beaufort under early pressure

A high-pressure area has been moving in over the Beaufort Sea lately. It's quite big and quite high in pressure. Environment Canada has the current pressure there at 1042 hPa:

I've coloured the land masses to make it easier to orient. I've also put in the red arrows to show which way the winds blow along the so-called isobars.

This is the second notable high of this year, following another big one in February that produced strong winds that pushed the ice away from the coast. This phenomenon called the Beaufort Gyre resulted in what we call a cracking event around here (see this blog post). Of course, the Arctic was plenty cold around that time and so the leads froze over again, but the marks are still visible on this AVHHR image (provided again by Environment Canada):

On the one hand those leads let heat escape from the ocean water, on the other hand the thin ice between the enormous floes will melt out easily as soon as sunlight and higher temperatures start taking over, possibly making the entire zone more vulnerable early in the melting season.

The reason I've decided to dedicate a blog post to this, has to do with the current ECMWF forecast for the coming 6 days:

2015/2016 Winter analysis

I think this winter is going to get studied like crazy,
for quite a while. It’s a very interesting time.
        Jennifer Francis, Washington Post

The extraordinary temperature anomalies in the Arctic since the start of the year haven't gone unnoticed in quite a few media outlets, and I apologize for not having joined the fray of actuality. On the other hand, context trumps actuality, as we need to compare to previous years and get a feel for what this prelude to the melting season may mean. In that sense, I'm early with this year's winter analysis (compared to last year).

Let's start studying like crazy, shall we?

It's a lot of text and images, so if you're feeling a bit tl;dr-ish today,
skip to the conclusion at the bottom of the page.

Surface air temperature

Here are the monthly temperature graphs for November-February in the Arctic Circle, from 2005/2006 to the past winter, based on the NCEP reanalysis dataset:

Last November saw the highest average monthly temperature in the 2005-2015 record, followed by a lower December, relatively speaking. Things then get a little bit crazy after the turn of the year, with the January 2014 record getting broken by almost 3 °C! February isn't far behind either, almost 1.5 °C higher than the already 'warm' February of 2014. This is unprecedented.

To see where temps were least low, I've created average temperature maps using the Daily mean composites page from NOAA's Earth Science Research Laboratory website, comparing the 2015/2016 freezing season to those preceding the years with the lowest minimums on record (click for a larger version):

An exceptional exception

Winter is supposed to be a time when things quiet down in the Arctic, animals hibernate in complete darkness, and all that can be seen from satellites is this great, icy mass getting bigger and bigger. That's how it goes most of the time, despite the spectacular summer sea ice losses of the past decades. But of course, there are exceptions, and this winter is one of those. In fact, it's an exceptional exception.

I want to highlight a couple of things to give you an idea of what's going on in the Arctic right now. As some of you may already know, this year's trend line is the lowest on record in practically every graph (see here). So far, it has played a major role in the breaking of Global sea ice area and extent minimum records, and it looks highly possible that last year's Arctic sea ice maximum record gets broken too. Mind you, that record was already spectacularly early and low, which is why I referred to it as Mad Max at the time.

It's a bit too early to be calling the max, which I vowed never to do again anyway, but here's the current situation on the Cryosphere Today sea ice area and JAXA sea ice extent graph (as provided by ADS-NIPR):

2015 peaked on this date in the CT SIA data set, but this year is currently 700K lower (last week's preliminary peak was almost 600K lower). The 2015 maximum occurred on February 15th in the JAXA SIE data set, but this year's preliminary peak is almost 274K lower. That's no small change, if things stay this way.

When area/extent is exceptionally low, it's usually a sign of something going on one side of the Arctic, while things are relatively quiet on the other side. This year, however, there's stuff going on on both sides of the Arctic. I'll start with the Pacific side of the Arctic, where regional extent is again very low in the Bering Sea, though high in the Sea of Okhotsk (these graphs are produced by Wipneus and can be found on the Regional Graphs page):

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):

Cracks and the mobility of ice in the Beaufort

As mentioned in the post on last week's weird winter weather, a large blocking high over the Beaufort Sea also caused a cracking that was a minor repeat of last year's spectacular and extensive cracking event. Although this one wasn't as notable (Jan. 1st image on the right was posted by Jim Hunt on the ASIF),
I'd like to share with you this article Chris Reynolds posted on his Dosbat blog a couple of days ago,
in which he discusses the effect thinning ice will probably have on the amount of cracking events occuring in the future:

Thinner Ice in Beaufort and Beaufort Breakups

Last February I posted about a break up of sea ice that occurred in the Beaufort Sea, now another break up has happened over the last week. It demands a post, but one looking at the bigger picture, indeed were I to try to go over what has happened in the last week the result would read surprisingly similar to my post of February 2013.

I'm still not totally convinced this is unusual, but there is reason from the scientific literature to expect more sea ice break ups in the Beaufort Sea.

First it's worth looking at the ice state as seen in polar orbiting infra red satellite images, source Environment Canada:

The Beaufort Sea is centre left of the image, fracturing is seen throughout the image, however Beaufort has been left heavily fractured, with fractures running along the coast of the Canadian Arctic Archipelago (towards the rose of compass points overlayed around the pole). As with last year this is because winds have set up a general clockwise motion of the pack placing ice under tension and giving rise to rapid parallel cracking.

Last year there was clear termination of cracks as they reached the thicker multi year ice, which could be identified from ASCAT, see first link of this post for details. That is less evident this year however it provided a clue that ice state in Beaufort (in 2013 virtually all first year ice following the 2012 record minimum) was playing a pivotal role in allowing the development of the fracturing.

Given the difficulty of ascertaining whether one, or even both of these events are unusual (I gave my opinion on that last year), perhaps a more fruitful question is this: Is there any reason to suspect that winter sea ice cracking might be becoming more intense than in the past?

Read the rest here.