Tag Archives: Arctic

4 Comments

The summer of 2016 saw the joint second lowest Arctic sea ice extent. But in the middle of October unusual Arctic weather has led to it becoming the lowest extent. At the same time, Antarctic sea ice extent has also reached record lows. Tamino has a simple and clear post about what a surprising thing this is.

The Northern Hemisphere Sea Ice extent from Tamino's blog
The Northern Hemisphere Sea Ice extent from Tamino's blog "Open Mind". The current year 2016 is in Red

 

Why is it so low?

The plot below shows the mean November Arctic sea ice extent, the sea ice extent on 16 November 2016, and the difference between the extents from 1993 to 2016. Regions shaded at the top end of the scale (the red colours) mean there is less ice now compared with in 1993.

The mean Arctic sea ice extent in November 1993, the daily sea ice extent on 16 November 2016, and the difference between them
The mean Arctic sea ice extent in November 1993, the daily sea ice extent on 16 November 2016, and the difference between them.

The stand out region (to me!) is North Russia where the Kara Sea is almost entirely clear, followed by Hudson Bay, Baffin Bay, East Greenland and the edge of the Chukchi Sea. I was interested in what was going on in the Kara Sea so I made a movie of the sea ice extent from 1 November 2016 to 16 November 2016.

Arctic sea ice 1 to 16 November 2016.
Arctic sea ice 1 to 16 November 2016.

The striking thing in the clip for November 2016 is that the sea ice extent has actually reduced in the Kara Sea!

The sea ice extent in Chukchi Sea is increasing, but very slowly - and you can see from my previous image that it is very low compared with 1993.

Clearly the Arctic is experiencing strange conditions at the moment. On the climatereanalyzer.org website you can see the 5-day forecast from 17 November 2016 (tomorrow).

The temperature departure from average is off the scale over the Arctic Ocean. It's much colder over Russia.

The 5 day forecast from 17 November 2016 from Climate Reanalyzer.org.
The 5 day forecast from 17 November 2016 from ClimateReanalyzer.org.

These are astonishing observations. When the winds change and the cold air currently over Russia ends up over the ocean I would expect it to freeze up rapidly (once the surface layers have cooled). But starting so late in the year the sea ice could end up thin enough for something impressive in the near future.

I made a gif of the full current Arctic growing season up to 16 November 2016.

I have already written a little about the this years Antarctic sea ice extent in the Antarctic Peninsula sea ice late winter 2016, in The Western Weddell Sea ice factory, in The development of the Amundsen Sea Polynya, in Dotson Getz Polynya ice growth, and in The Prince Gustav Channel is opening.

For interest, I chose November 1993 for comparison for two reasons, first it’s just before the big Arctic sea decline, and secondly I was in the Arctic for 4 months that year doing my PhD research.

Tamino is noting that the global sea ice is "About 6.9 standard deviations below the 1981-2010 mean." . Amazing times.

1 Comment

It is October and it is the Arctic sea ice growing season. The MODIS imagery yesterday shows this beautiful image of sea ice on the North East Greenland coast.

North West Greenland in a MODIS image 5 October 2016
North East Greenland in a MODIS image 5 October 2016 from the TERRA satellite

The image below shows roughly where we are looking:

...continue reading

Yet more beautiful MODIS imagery showing some wonderful patterns in a plankton bloom in the Barents Sea.

Plankton patterns in the Barents Sea
Plankton patterns in the Barents Sea

The screen grab is from the 250m resolution imagery, and the whole arctic panel shows just where the bloom is located.

The Arctic on 29 July 2015 in MODIS imagery
The Arctic on 29 July 2015 in MODIS imagery

This particular region seems to show plankton blooms regularly in the MODIS imagery and the Wikipedia page has a similar (but not as nice) image dated summer 2009.

 

 

2 Comments

The MODIS sensor satellite imagery is showing a beautiful and evolving large plankton bloom in the Chukchi Sea at the moment.

Plankton bloom in the Chukchi Sea, as seen in the MODIS sensor on 23 June 2015.
Plankton bloom in the Chukchi Sea, as seen in the MODIS sensor on 23 June 2015. Alaska is on the LEFT and Russia the RIGHT. The image is looking SOUTH.

The plankton are the lighter green bands I've labelled and the full image is available at an astonishing 250m resolution.

...continue reading

1 Comment

I was enjoying my polar books the other night and came across a quote attributed to everyone's  favourite humanitarian polar explorer and scientist, Fridtjof Nansen.

Fridtjof Nansen
Fridtjof Nansen, 1915, from the George Grantham Bain Collection

If I were not a Norwegian, I would be an Englishman rather than belong to any other nation

Nansen is quoted in Fridtjof Nansen, his life and explorations, by James Arthur Bain, 1897.

Fridtjof Nansen quoted by James Bain, 1897. Page 45

Fridtjof Nansen quoted by James Bain, 1897. Page 45

It's hard not to be in awe of Nansen.

...continue reading

2 Comments

This plot shows the Antarctic sea ice extent, the Arctic sea ice extent, and the total sea ice extent plotted against time.

Arctic, Antarctic and total sea ice extent 2012

Like in previous post I chose 2012 only because it is the most recent complete year in this data set.

Take a look at the minimum, the maximum and the range of the sea ice extent.

Antarctic: Minimum Antarctic sea ice extent 3.11 x 106 km2
Maximum Antarctic sea ice extent 19.48 x 106 km2
Range of the Antarctic sea ice extent 16.37 x 106 km2
Arctic: Minimum Arctic sea ice extent 3.37 x 106 km2
Maximum Arctic sea ice extent 15.25 x 106 km2
Range of the Arctic sea ice extent 11.88 x 106 km2

The range of Antarctic sea ice extent is 16.37 x 106 km2, and the range of the Arctic sea ice extent is 11.88 x 106 km2.

The Antarctic and the Arctic do not "balance" in sea ice extent - the Antarctic variations are much larger.

Look at the shape of the annual cycle. I said previously that in the Antarctic the seasonal cycle of sea ice extent is not symmetrical. Sea ice grows slowly and steadily before decaying relatively rapidly: the melt period is shorter than the growth period.

In the Arctic the time sea ice grows is roughly similar to the time sea ice melts.

So they do not "balance". The seasonal cycles, ranges, minimums and maximums are  different,

The annual cycle of the Arctic and Antarctic sea ice extent is very different.

We know that the extent and thickness of the Arctic sea ice is decreasing. See for example what Tamino wrote in Feb 2014.

But what about the Antarctic? The extent of the sea ice has broken records for the satellite era. (This is a very funny article making some claims about what that means - if you want a clue what is the difference between glacial ice and frozen sea water?).

Some believe the observed reduction in the Arctic sea ice volume is balanced by the increase in the Antarctic sea ice extent. So we should look at the black line in the plot above.

I will get onto why I don't think that is a good idea in a coming post.

Here is the plot animated with 1 second = 10 days

 About the data

The data set is from the National Snow and Ice Data Center Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS Passive Microwave Data.

 

11 Comments

This is the 2012 sea ice extent for both the Arctic and the Antarctic. The day of year and the calendar day are at the bottom.

I chose 2012 only because it is the most recent complete year in this data set.

My reason for making this video is because there have been a couple of huge news stories recently about the West Antarctic Ice Sheet:

On 12 May 2014 we heard that for all intents and purposes the West Antarctic Ice sheet is doomed (here is the primary research which is open access).

Then on 19 May 2014 we were told that Cryosat observations had shown that the loss of ice from Antarctica had increased quite a lot (here is the primary research).

For excellent commentary on these stories you can visit Carbon Brief, or Antarctic glaciers.org.

But whenever there is a big story about the decay of the West Antarctic Ice Sheet - which remember is land based glacial ice, some instantly point to this being not important because sea ice in Antarctica has been at record levels.

People who suggest that the observed decrease in glacial ice is somehow balanced by the observed increase in Antarctic sea ice extent are wrong. The sea ice is generally only a couple of metres thick and it is telling us quite a different climate story.

Over the next few posts I will try and explain why the decrease of Arctic sea ice is not balanced by an increase in Antarctic sea ice extent, and why there is no contradiction in glacial ice at the edge of the Antarctic continent decaying whilst simultaneously the sea ice is  at record extent.

 

[If anyone want the clip, also the Arctic and Antarctic as separate files in various large sizes and formats just send me an email at my work address - you will find a link on the "About me" page. And I will send you a dropbox link. I am a big fan of Creative Commons and Open Educational Resources. ]

-

The data is from the US Defense Meteorological Satellite Program (DMSP), and the data is freely accessible from the National Snow and Ice data Centre.

 

1 Comment

Last week the Royal Society (UK), and the National Academy of Sciences (NAS) released a good PDF booklet called Climate Change: Evidence & Causes.

In the words of the US NAS

"Climate Change makes clear what is well-established and where understanding is still developing. It echoes and builds upon the long history of climate-related work from both national academies."

You can read the background at the Royal Society site, and Carbon Brief provides a synopsis so good I can't add much.

But I will talk about the cover. Here is a screen grab.

The Cover of the Royal Society Climate Change report
The Cover of the Royal Society Climate Change report

I think it's beautiful. I love the way the golden light reflects on the young sea ice. In fact I think it is so beautiful that we used it on the cover of a book I partially wrote and edited for my employer in 2011.

The Cover of the Open University Frozen Planet Coursebook
The Cover of the Open University Frozen Planet Coursebook

The original is an iStock image called "Polar bear on ice close to golden glittering water". Now that is not what I would call it - but then I wasn't fortunate enough to be in a helicopter at that time of the year, and so I don't get to choose.

The Royal Society / NAS had cropped the bear from the image so they used the segment in the yellow rectangle below...

S175 Cover with Crop
The cover of the S175 Book with the crop

They actually rotated and stretched it slightly to completely miss the bear - although there are still clearly bear footprints in the version they use.

I am sure they did that because they did not want to get into the whole "poor polar bear looking over the melting ice" conversation. All the way back in 2012 Carbon Brief included "sad polar bear on melting ice" as one of their Nine climate change pictures I really don't need to see again.

So why did I use it? To me the polar bear is in its natural habitat. The bear is wandering over decaying sea ice and refrozen melt water. Our book is filled with the science of how and why the ice grows and melts, and what adaptations and strategies the animals use to survive, plus lots of other science. The polar bear's Latin name is ursus maritimus - which in English is "sea bear": open water and ice are part of their habitat.

That nuance is not possible in a short but excellent PDF report on climate change, so

I imagine they chose the beautiful light.

In hindsight I think I would have used another image. But only because if you go to the trouble of writing a book, then you would want to keep it special.

The problem I had at the time was that I was not very good at choosing any of my own images.

-

The title of the post points to the book Setting Free the Bears by John Irving. It's a book I like and it is about two young people releasing the animals from Vienna zoo after the Second World War.

I don't usually work on this sort of thing, but very recently I have been writing about hazards caused by the cryosphere. A major hazard is of course the avalanche - whether ice, snow, or a mixture.

This video was posted on You tube (with the tag line "Courtesy Vertical Solutions"), and it shows the impact of a snow and ice avalanche on the Alaskan road network on the 26 January 2014.

 

I tweeted it yesterday and the glaciologist Mauri Pelto replied

 

I'll try to remember to keep an eye online to see the outcome.