Tag Archives: sea ice

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Quick post on the Maud Polynya in the Weddell Sea that I wrote about last week. This is the sea ice data 17 September 2017, and the polynya is both clear and large.

The location of the polynya over Maud Rise. Sea ice data from DMSP SMMI.
The location of the polynya over Maud Rise. Sea ice data from DMSP SMMI.

An enlargement of the polynya shows that it is practically open water.

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The sea ice in the Antarctic is at minimum extent in February and expands through to mid September.

This movie shows the Antarctic sea ice extent from 1 Feb to 25 July 2017. The data come from the DMSP SMMI sensor, and it shows the expansion of the sea ice as winter progresses.

 

For me the stand out feature is how late the sea ice expands in the Bellingshausen Sea. I think this is a feature of the super low sea ice last year, and the amount of time it took to lose the extra heat absorbed by the ocean.

The NSDIC data set shows the sea ice is lower than we've seen before by satellite.

Antarctic sea ice extent to 26 July 2017 from NSIDC.
Antarctic sea ice extent to 26 July 2017 from NSIDC.

Currently the Antarctic sea ice extent is ~450 thousand km2 below 1981-2010 median.

~7-8 weeks of sea ice expansion to go.

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The sea ice in the Arctic is at maximum extent in February and retreats through to mid September.

This movie shows the Arctic sea ice extent from 1 Feb to 25 July 2017. The data come from the DMSP SMMI sensor, and it shows the retreat of the sea ice as summer progresses.

You can see from the NSDIC that Arctic sea ice extent is tracking close to the 2012 minimum, and about ~1.6 million km2 below 1981-2010 median.

Arctic sea ice extent to 26 July 2017 from NSIDC.
Arctic sea ice extent to 26 July 2017 from NSIDC.

To see where the sea ice "isn't" you can see the gif I made for a post last week.

The mean Arctic sea ice for the years 1989-93 on 27 July, the sea ice concentration on 27 July 2017 and the difference between the two data sets. Blue shades imply more sea ice and reds imply decreased sea ice compared with the mean. The original data come from the DMSP SMMI data set at the NSIDC.
The mean Arctic sea ice for the years 1989-93 on 27 July, the sea ice concentration on 27 July 2017 and the difference between the two data sets. Blue shades imply more sea ice and reds imply decreased sea ice compared with the mean. The original data come from the DMSP SMMI data set at the NSIDC.

In that post I said

Things that stand out for me are the virtually open water in the Barents and Kara Seas.

~6-8 weeks of melt to go...

Today the NASA Earth Observatory Website has published a beautiful image from 29 June 2017 of Hudson Bay in a post called Lingering Sea Ice on Hudson Bay.

Lingering Sea Ice on Hudson Bay
Lingering Sea Ice on Hudson Bay. Image NASA Earth Observatory.

To the untrained eye the sea ice in the bay looks like cloud, but if you look at the still from the movie above on the same day, the sea ice is clear.

Hudson Bay 28 June 2017
Hudson Bay 28 June 2017

The NASA blog post talks about how polar bears were hunting in this sea ice.

 

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I thought it was time to look at the sea ice data as the summer Arctic melt proceeds.

The image below shows the mean sea ice extent 1989-93 on 22 July, the sea ice extent 22 July 2017, and the difference between the two data sets. Reds imply less sea ice than the mean 1989-93, and blues an increased sea ice extent.

The mean Arctic sea ice for the years 1989-93 on 22 July, the sea ice concentration on 22 July 2017 and the difference between the two data sets. Blue shades imply more sea ice and reds imply decreased sea ice compared with the mean. The original data come from the DMSP SMMI data set at the NSIDC.
The mean Arctic sea ice for the years 1989-93 on 22 July, the sea ice concentration on 22 July 2017 and the difference between the two data sets. Blue shades imply more sea ice and reds imply decreased sea ice compared with the mean. The original data come from the DMSP SMMI data set at the NSIDC.

As we would expect, compared with the 1989-93 data the sea ice edge is consistently further north. Things that stand out for me are the virtually open water in the Barents and Kara Seas. This region was very slow to freeze over in the autumn and winter of 2016, so I would have expected the sea ice there to be relatively thin at the end of the Arctic winter.

Also the Chukchi Sea is opening.

Overall the area of the Arctic Ocean covered with sea ice is low. Some will note it is currently above the record low in 2012, but it's only 90,000 kmabove that. To me that is not that significant.

Arctic sea ice extent to 22 July 2017 from NSIDC.
Arctic sea ice extent to 22 July 2017 from NSIDC.

What is significant is the sea ice 22 July 2017 is ~1.7 million kmbelow the median extent from 1981-2010.

I looked a couple of days ago at the sea ice in the North West Passage (19 July 2017), and it is starting to open up.

The North West Passage. Image 22 July 2017 from the Suomi National Polar-orbiting Partnership Visible Infrared Imaging Radiometer Suite.
The North West Passage. Image 19 July 2017 from the Suomi National Polar-orbiting Partnership Visible Infrared Imaging Radiometer Suite.

The yellow line traces out possible ship routes through the North West Passage and whilst there is still ~1200 km of sea ice on that route, when you compare the region to the longer term data you can see how low this is compared the historical record.

The difference in the sea ice in the NW Passage on 22 July 2017 compared with the mean for the years 1989-93 on 22 July. Blue shades imply more sea ice and reds imply decreased sea ice compared with the mean. The original data come from the DMSP SMMI data set at the NSIDC.
The difference in the sea ice in the NW Passage on 22 July 2017 compared with the mean for the years 1989-93 on 22 July. Blue shades imply more sea ice and reds imply decreased sea ice compared with the mean. The original data come from the DMSP SMMI data set at the NSIDC.

It may be this year that the passage may not open at all, but taken together the two plots are a a good example of how we can expect the north west passage to become consistently open as the Arctic continues to warm.

 

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Approaching the middle of May and well into the Arctic sea ice retreat we can see that the sea ice extent (area of ocean with at least 15% sea ice) is still well below the mean over the satellite record.

Arctic sea ice extent to 53 May 2017 from NSIDC.
Arctic sea ice extent to 53 May 2017 from NSIDC.

I like a geographic perspective, so this is the mean sea ice extent 1989-93 on 13 May, the sea ice extent 13 May 2017, and the difference between the two data sets. Reds imply less sea ice than the mean 1989-93, and blues an increased sea ice extent.

The mean Arctic sea ice for the years 1989-93 on 13 May, the sea ice concentration on 13 May 2017 and the difference between the two data sets. Blue shades imply more sea ice and reds imply decreased sea ice compared with the mean. The original data come from the DMSP SMMI data set at the NSIDC.
The mean Arctic sea ice for the years 1989-93 on 13 May, the sea ice concentration on 13 May 2017 and the difference between the two data sets. Blue shades imply more sea ice and reds imply decreased sea ice compared with the mean. The original data come from the DMSP SMMI data set at the NSIDC.

There appears to be a general trend of the Arctic sea ice edge retreating between the two data sets, but I think this is in places meteorological - that is the winds are compressing the sea ice. I think this because there is a lot of blue (i.e. more sea ice than the 89-93 mean) just north of the sea ice edge.

The Bering Sea appears relatively sea ice free at this time.

On the North West of Greenland you can also see that the North Water Polynya has opened up.

The location of North Water polynya. Image from MODIS data 14 May 2017.
The location of North Water polynya. Image from MODIS data 14 May 2017.

When you zoom in you can see the open water.

North Water polynya. Image from MODIS data 14 May 2017.
North Water polynya. Image from MODIS data 14 May 2017.

North Water is a very famous whale habitat and as the light increases we may see a plankton bloom here.

 

Sea ice is still relatively low in both the the Arctic spring and Antarctic autumn. A geographical perspective always helps so here is the status of the sea ice concentration 23 April 2017 for both polar regions.

The Arctic

Here is the sea ice concentration 23 April 2017 compared with the  1989-1993 mean on the 23 April. Red shades = less sea ice than the 1989-93 mean on 23 April, and Blue shades = more sea ice than the 1989-93 mean on 23 April.

The mean Arctic sea ice for the years 1989-93 on 23 April, the sea ice concentration on 23 April 2017 and the difference between the two data sets. Blue shades imply more sea ice and reds imply decreased sea ice compared with the mean. The original data come from the DMSP SMMI data set at the NSIDC.
The mean Arctic sea ice for the years 1989-93 on 23 April, the sea ice concentration on 23 April 2017 and the difference between the two data sets. Blue shades imply more sea ice and reds imply decreased sea ice compared with the mean. The original data come from the DMSP SMMI data set at the NSIDC.

The stand out regions for me are once more (as in my post in January), the Northern Barents Sea is relatively low, along with the Bering Sea and the Sea of Okhotsk. There is a consistent retreat of the ice edge almost everywhere, and comparatively a lot of open water in Hudson Bay.

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Watching the sea ice extent this summer in Antarctica has been a bit surprising. The Antarctic sea ice extent has been tracking at record lows virtually the whole austral summer. We are very close now to the expected sea ice minimum, and this is where we are:

Antarctic sea ice extent 12 Feb 2017 & diff from mean 1989-93 on same day. Blues imply more ice and reds imply less compared with the mean.
Antarctic sea ice extent 12 Feb 2017 & diff from mean 1989-93 on same day. Blues imply more ice and reds imply less compared with the mean.

On the left is the sea ice extent from the DMSP satellite 12 February 2017, and on the right the difference between the mean sea ice extent on 12 Feb over the period 1989-93 and 12 Feb 2017. I chose this time period as the cycle has been generally quite stable from year to year.

The current sea ice extent is:

Antarctic sea ice extent. Downloaded from NSIDC 14 February 2017.
Antarctic sea ice extent. Downloaded from NSIDC 14 February 2017.

It's clear the sea ice over the summer 2016-17 is showing historic lows. But it's also clear from the sea ice extent above that there is little sea ice left to melt out before the summer turns. Where the sea ice remains - mainly in the Weddell Sea and along the coast of Wilkes Land it is clearly densely packed. If the winds change and the remaining sea ice is decompressed then the extent may fall some more.

This is an animation of the Antarctic sea ice extent from 1 January 2017 to 12 February 2017:

The Antarctic sea ice extent 1 January to 12 February 2017. Data from DMSP SMMI
The Antarctic sea ice extent 1 January to 12 February 2017. Data from DMSP SMMI

And finally the difference between the mean sea ice extent by day for the 5-year period 1989-1993 minus the concentration from 1 Jan to 12 Feb 2017. Blue shades imply an increased sea ice extent compared with a 5-year mean, and reds imply a decreased sea ice extent.

The difference between the mean sea ice extent by day for the 5-year period 1989-1993 minus the concentration from 1 Jan to 12 Feb 2017. Blue shades imply an increased sea ice extent compared with a 5-year mean, and reds imply a decreased sea ice extent.
The difference between the mean sea ice extent by day for the 5-year period 1989-1993 minus the concentration from 1 Jan to 12 Feb 2017. Blue shades imply an increased sea ice extent compared with a 5-year mean, and reds imply a decreased sea ice extent.

Not long until the Antarctic sea ice minimum.

The Metropolitan Museum of Art has made more than a third of a million images both public domain and searchable online. This is one of my current favourites:

An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford and painted in 1871.

An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871
An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871

If you look really closely you can see it is a steam assisted ship.

Detail from: An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871.
Detail from: An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871.

I really like the colours in the sea ice in the foreground. It's hard not to see that when you are in the sea ice.

Detail from: An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871.
Detail from: An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871.

And let's not forget the ice bear in the foreground.

 

Detail from: An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871.
Detail from: An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871.

The caption on the Met page makes clear they were hunting this bear:

In 1861 the marine painter William Bradford made the first of his eight expeditions to the Arctic. This painting, based on photographs and sketches produced during his final trip, in 1869, shows the artist’s steamer, Panther, plying its way through the summer ice along the northern coast of Greenland. Panther was one of numerous vessels engaged in the search for the Northwest Passage between the Atlantic and Pacific Oceans. According to Bradford’s journal, the ship’s crew had decided to hunt the polar bear seen in the foreground, “anxious to possess so fine a skin,” but the bear made a parting glance over its shoulder before heading for the water, managing to escape its pursuers.

But it is art for sure.

There is no way you could get an iceberg with this sort of freeboard close to the shore...

Detail from: An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871.
Detail from: An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871.

And I love the detail of a wrecked ship mast on the left.

Detail from: An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871.
Detail from: An Arctic Summer: Boring Through the Pack in Melville Bay by William Bradford, 1871.

There is a long history of romantic artists balancing the struggle of man against the icy wastes. My all time favourite in that category is Landseer's Man Proposes, God Disposes.

Man Proposes, God Disposes by Edward Landseer 1864.
Man Proposes, God Disposes by Edward Landseer 1864.

Thanks Metropolitan museum for putting it online.

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Sea ice continues to be very low in the Arctic this winter. A geographical perspective always helps so here is the status of the sea ice concentration 18 January 2017 compared with the  1989-1993 mean on the 18 January.

RED shades = less sea ice than the 1989-93 mean on 18 January.

BLUE shades = more sea ice than the 1989-93 mean on 18 January.

The mean Arctic sea ice for the years 1989-93 on 18 January, the sea ice concentration on18 January 2017 and the difference between the two data sets. Blue shades imply more sea ice and reds imply decreased sea ice compared with the mean. The original data come from the DMSP SMMI data set at the NSIDC.
The mean Arctic sea ice for the years 1989-93 on 18 January, the sea ice concentration on18 January 2017 and the difference between the two data sets. Blue shades imply more sea ice and reds imply decreased sea ice compared with the mean. The original data come from the DMSP SMMI data set at the NSIDC.

A few interesting areas that caught my eye:

Geographic Areas in the Arctic with a strong absence of sea ice on 18 January 2017.
Geographic Areas in the Arctic with a strong absence of sea ice on 18 January 2017.

The first highlight region is the Northern Barents Sea. Sea ice has been very low here all winter, and this situation continues. Because the sea ice has been very late, the polar bears on Svalbard will be impacted, and it has been an issue in Longyearbyen....

Polar bears in Longyearbyen
Polar bears in Longyearbyen.

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The Arctic

It's been quite a year in the Arctic. Over the winter 2015/6 we had the strongest and coldest Arctic polar vortex of the last 68 years. This contributed to a low maximum in Arctic sea ice extent. At that stage only the locals and the scientists were looking, and I wrote about this in a blog post called Arctic sea ice 2016. This was followed by the joint second lowest Arctic summer sea ice extent.

Unusual weather in the early winter led to records being broken and the sea ice the Arctic sea has been the lowest recorded in the satellite record for the time of year.

Where are we at the Northern winter solstice?

The mean Arctic sea ice for the years 1989-93 on 21 December, the sea ice concentration on 21 December 2016 and the difference between the two data sets. Blue shades imply more sea ice and reds imply decreased sea ice compared with the mean. The original data come from the DMSP SMMI data set at the NSIDC.
The mean Arctic sea ice for the years 1989-93 on 21 December, the sea ice concentration on 21 December 2016 and the difference between the two data sets. Blue shades imply more sea ice and reds imply decreased sea ice compared with the mean. The original data come from the DMSP SMMI data set at the NSIDC.

The ice edges have retreated compared with 1989 - but as I wrote about in Record Low Arctic Sea Ice Extent we still have the very low sea ice concentration in the Barents Sea. There is also  still a very low concentration region north of the Bering Strait but the the Chukchi Sea and Hudson Bay have mostly frozen over.

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