June 2024

Mark Brandon • August 23, 2018

A story on the BBC Business News website about the Northern Sea Route caught my eye:

BBC Business News “Container ship to break the ice on Russian Arctic route”. 21 August 2018.

The Danish ship Venta Maersk, (Maersk Line, ice-class Baltic feeder vessel  of 3,600 containers) is going to attempt to transit across the Kara Sea, the Laptev Sea and the East Siberian Sea.

Maersk said: “The trial passage will enable us to explore the operational feasibility of container shipping through the Northern Sea Route and to collect data.”

There is generally a lot happening in Arctic sea ice news at this time of the year as we head to the annual summer minimum extent, and current sea ice extent is currently about 1.6 million km² below the 1981-2010 mean.

Sea ice in the Arctic currently about 1.6 million km2 below the 1981-2010 mean. 21 August 2018.

Given that the trend of minimum ice extent has been relentlessly downwards since the start of the satellite record:

Annual Arctic minimum sea ice extent. Data from from NSDIC.

we could expect the Venta Maersk to have potentially an easy passage.

But that is rarely true in polar seas – even at the height of what will be the Arctic summer.

A look at the distribution of the current sea ice extent is interesting.

Arctic sea ice 21 August 2018, mean Arctic sea ice 21 August 1989-93 and difference between the two. Reds indicate absence of sea ice compared to the older data and blues indicate increased. The yellow box indicates a region where there is much more sea ice than we could expect.

There is more sea ice in the East Siberian Sea than we could expect (~40% more than the 1989-93 mean), and a look at the latest “near real time” (end of April 2018) ice thickness data from CPOM show that the ice in this region was quite thick at the start of the summer melt season.

Arctic sea ice thickness processed at UCL from CryoSat’s SAR mode data: NOTE THIS IS END OF APRIL 2018. NRT Service Suspended during Arctic summer (May-Sept).

It is possible the Venta Maersk could find the going slow, but she is a polar rated ship designed to work in the Baltic, and by staying close to the coast she could avoid the ice completely.

It is an interesting way to move a Baltic ship from it’s build location in China to its planned operational area, and one to watch over the next month.

The excellent researcher Dr Nathanael Melia wrote a great post about the potential of Arctic Shipping on Carbon Brief in 2016: What will sea ice loss mean for Arctic shipping?

**

Interestingly if you look at the Cryosat sea ice thickness map north of Greenland you can see that at the end of the winter the sea ice thickness was already relatively low. (See the story in the Guardian: Arctic’s strongest sea ice breaks up for first time on record). The thickest sea ice is further to the west north of the Canadian Arctic Archipelago.

Arctic sea ice thickness processed at UCL from CryoSat’s SAR mode data: NOTE THIS IS END OF APRIL 2018. NRT Service Suspended during Arctic summer (May-Sept).

***  UPDATE From Twitter

From Dr Stefan Hendricks at the Alfred Wegener Institute

Tweet from Dr Stefan Hendricks.

**** Update 2 from Twitter

From Dr Ruth Mottram at the Danish Meteorological Institute.

Tweet from Dr Ruth Mottram. Posted in Science. Tags: Arctic, Maersk, Northern Sea Route, sea ice, ship on August 23, 2018 by Mark Brandon.

RRS James Clark Ross is on route to Rothera, the largest British Antarctic Survey research Station. In the next few hours to get to the base she will have to pass what looks like a continuous sea ice band about 15 km wide, before she enters some looser pack. To get their she will have to do some icebreaking. The band of ice has been stationary for over a week.

If you want to follow the action the ship has a webcam, or you can check the Radio Office Mike Gloistein’s update page. The web cam is as I write this but I’m sure it will be switched on soon.

The MODIS satellite image off Adelaide Island 25 Nov 2016, with the location of the RRS James Clark Ross 0000 28 November 2016.

The satellite image is from 25 November 2016, but the sea ice doesn’t look like it has changed significantly since then. I chose that date simply because it is relatively cloud free.

The ship has about 130 km to run so could dock later today – but it could be tomorrow given the sea ice.  The path I have shown in red looks quite a long way south of the Island – but close in it gets quite shallow. If your interested in your polar history the ship RRS John Biscoe was actually abandoned in this region for a while before being rescued by the German ship Polarstern.

This is as The Antarctic Report points out, quite early for the ship to reach the base.

The track of the ship is online along with the weather conditions it is experiencing. At at about 0°C it is currently warmer than a lot of the UK.

Dr Helen Jones is the doctor on the James Clark Ross and she is writing a blog Baby it’s cold down here.

–UPDATE 1050z —

You can see James Clark Ross is now in the ice and heading for the band of relatively open water at the southern tip of Adelaide Island.

This is an image from the webcam.

I wrote about what a water sky is a while ago.

–UPDATE 0650z 29 November —

It was too early and the RRS James Clark Ross didn’t make Rothera.

To quote the radio officer Mike Gloistein:

The sea-ice around the bottom of Adelaide Island has been heavy and whilst (for those of you who look at the satellite pictures) there are some leads and areas of open water,  they are close to land and if we took that route (which also includes shallow water and rocks) and the weather then pushed the ice inland,  the ship could easily become stuck between a rock and a hard place.

And get stuck just like the John Biscoe…

Mark Brandon • September 27, 2016

On 26th September 2016 the MODIS sensor on The TERRA satellite captured this beautiful image of South Georgia, with Iceberg A66 drifting past.

Iceberg A66 passing South Georgia captured in a MODIS image on the 26 September 2016. The image is available on a KML file on the MODIS Websites.

The iceberg A66 is about 15 km at it’s widest point in this image.

We can do a bit simple maths. Estimate the iceberg has a 200 m thickness and it is triangular in shape with a base of ~4 km.

the volume =  0.5 x 15 km x 4 km x 0.2 km = 6 km³.

So the relatively small A66 contains of 6000 gigtons of water. It’s a lot. But it’s not a lot.

Icebergs get their reference number depending on where they originate from. This one has an identifier “A” which means it came from the sector 0° to 90°W – that’s the Bellingshausen and Weddell Sea region. You can track icebergs like this both visually – like in in the image above – or using something called a Scatterometer. A scatterometer can measure the winds over the ocean, and because the winds change over the ice one can track the icebergs. Prof David Long at Brigham Young University provides an excellent database of Antarctic iceberg data based on that idea (this is their research paper on how they do that).

If we look at the location data from the ASCAT sensor you can see that A66 is at the tip of the Antarctic Peninsula – but this data is only from this year. I will have to dig a little deeper. A job for later.

The track of Iceberg A66 from the BYU database

Once the icebergs reach the edge of the Weddell Sea they get to South Georgia very quickly. I did write about that in a paper in the OU database Physical oceanography in the Scotia Sea during the CCAMLR 2000 survey, austral summer 2000.

And some of these icebergs (although not A66) ground at South Georgia and ultimately can affect the ecosystem. Jon Amos wrote about some work I did at a San Francisco conference  in 2010 about that – it’s still available on the BBC website: Giant icebergs head to watery end at island graveyard.

Giant icebergs head to watery end at island graveyard. By Jon Amos

Overall A66 is nothing special, this is not an unusual observation.

It is a beautiful image though.

Posted in Science. Tags: A66, iceberg, South Atlantic, South Georgia, Weddell Sea on September 27, 2016 by Mark Brandon. Mark Brandon • January 28, 2015

The South West Atlantic is a very productive part of the global ocean. This MODIS image from the Terra satellite shows the east coast of Argentina and the Falkland Islands. The ocean between is filled with swirls of lighter colour which are a plankton bloom along the continental shelf of South America.

Terra/MODIS Image captured 21 January 2015 14:00 UTC. FULL IMAGE LINK

The high plankton productivity means that there is food for the higher predators – and this region is famed as an extraordinarily rich squid fishing ground. In 2014 the fishery apparently took over 1/4 million tons of the squid Illex argentinus.

…continue reading →

Posted in Science. Tags: Argentina, Falkland Islands, Illex argentinus, oceanography, South Atlantic, squid on January 28, 2015 by Mark Brandon.

Project MIDAS publicised on Friday that a huge iceberg is going to calve from the Larsen C Ice Shelf. This was written up a a great story on the BBC news website Huge Antarctic iceberg poised to break away.  I understand a little about this stuff so got drawn into the media around it. Here is a BBC News interview on 6 January 2017.

It was great to see Antarctica in the news and it was brilliant to see so many high quality interviews from so many colleagues to different outlets. I may try and collate some of these in the next few days.

Mark Brandon • November 14, 2016

The Prince Gustav Channel was covered by an ice shelf which collapsed in the 1990’s, and for many years it was possible to sail a ship around James Ross Island.

Recently it has been covered with sea ice frozen to the land – we call this fast ice, and it’s usually only a few metres thick of frozen sea water – rather than hundreds of metres thick snow derived ice shelf.

Recent images from the TERRA satellite show that this fast sea ice is finally breaking out.

It’ll soon be possible to circumnavigate James Ross Island once more.

The Prince Gustav Channel early spring Antarctic summer 2016/7 from MODIS satellite imagery on the TERRA satellite.

This map shows the location of the channel.

The Antarctic Peninsula showing the location of the Prince Gustav Channel.

Now it has started I wonder how long it will take to finally clear. Or more fun, I wonder if tour ships will be able to get around the island?

Posted in Science. Tags: Antarctic Peninsula, fast ice, MODIS, Prince Gustav Channel, sea ice on November 14, 2016 by Mark Brandon.

Mark Brandon • October 26, 2017

As daylight has returned to Antarctica it is straightforward to pick out polynya forming on the edge of the Antarctic continent.

This one by the Stange Ice Shelf and Rydberg Peninsula caught my eye. It is a latent heat polynya formed as the winds push the sea ice away from the land to reveal the ocean that appears black beneath.

The wispy trails of grey which appear in the black are new sea ice forming as frazil ice.

A latent heat polynya forming in front of the Rydberg Peninsula and Stange ice Shelf, 22-26 October 2017.

This is the location of the peninsula.

The location of the Rydberg Peninsula.

I visited that area in 2007 and took this picture. You can a thin skim of young nilas ice in front of the ice shelf, and sea smoke too.

The Stange Ice Shelf with a thin skim of sea ice in front. Posted in Science. Tags: antarctica, frazil ice, polynya, Rydberg Peninsula, satellite, sea smoke, Stange Ice shelf on October 26, 2017 by Mark Brandon.

Mark Brandon • January 24, 2017

The sea ice around Antarctic is currently still at an historic low. As usual I think it is good to look at a geographic perspective on the sea ice distribution. This is the sea ice concentration 22 January 2017 compared with the  1989-1993 mean on the 22 January.

RED shades = less sea ice than the 1989-93 mean on 22 January.

BLUE shades = more sea ice than the 1989-93 mean on 22 January.

The mean Antarctic sea ice for the years 1989-93 on 22 January, the sea ice concentration on 22 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 Amundsen Sea has very low sea ice

Amundsen Sea has very low sea ice in January 2017

Probably for me the most striking feature is the extremely low sea ice concentration from Pine Island Bay through to the Ronne Ice Shelf – this is the Amundsen Sea. We are not going to see much more retreat of of the sea ice in this sector as it has already melted. I think it will stay open water until the freeze up begins some around the end of February. It would have been a great year to do ship based oceanography along that coast. I wonder if their could be an impact on ice shelf melt here. It is possible but as you can see from this article – it is water away from the surface and a few hundred metres deep that is in contact with the glacial ice in the Amundsen Sea Embayment, Overall this has to be a result of the recent El Nino, and is a follow on from the polynya events we saw hear in the late winter.

The Bellingshausen Sea has very relatively high sea ice

In contrast you can see it would not be a good year to be working in the Bellingshausen Sea.

Sea ice extent is currently relatively high in the Bellingshausen Sea.

Nevertheless, as expected, it was possible to finally relieve the British Antarctic Survey Rothera Base in January.

The Weddell Sea is a game of two halves

Sea ice in the Weddell Sea is now compressed against the Antarctic Peninsula

The Weddell Sea ice is at this stage in the summer is compressed against the Antarctic Peninsula. This means that there is heavier sea ice to the close to the Peninsula, and much lower sea ice than expected in the rest of the Weddell Sea. If you look at the MODIS Terra Image you can pick out a very sharp sea ice edge.

MODIS image from the TERRA satellite 23 January 2017. The sea ice edge in the Weddell Sea is very sharp.

Shackleton would have been in trouble this summer if he was heading to Elephant Island.

Towards the annual Antarctic sea ice extent minimum.

We expect the sea ice to reach a minimum towards the end of February. Clearly there are places where there is no more sea ice to melt. Where sea ice is present, it is all down to winds over the next month. If they change and move the pack towards open water then – just as we have seen in the Arctic, the concentration could fall much lower. If the winds continue as they have then we could expect the extent fall to slowly as the seasonal melt continues.

Overall it is still to be likely a record breaking year in the Antarctic sea ice extent record.

Posted in Science. Tags: Amundsen Sea, antarctica, Bellingshausen Sea, MODIS, sea ice extent on January 24, 2017 by Mark Brandon.

Navigation charts in Antarctica may not be as good as you think. It makes sailing in those regions a little more exciting than you could hope. Here is an example.

The coastline of Rothschild Island just to the west of Alexander Island, Antarctica. The navigation chart says the coastline location could be 5 miles in error

Five miles wrong… What does that mean?

Here is London with a 5 mile radius circle drawn on it.

London with a 5 mile circle drawn on it.

If you sailed your ship to a position – say the edge of Rothschild Island, you would not know the exact location of that coast to within the radius of that circle.

Just get your head around that. In this age of satellites, in 2016 we don’t know the location of coastline of Antarctica to the same level of accuracy that we already know the topography of Mars, Venus and our Moon.

Why are they so bad?

As usual there are lots of reasons. Most of the coastlines were mapped out by people on sailing ships and huskie drawn sledges decades before the satellites were launched. That means the outlines of the coasts and water depths tend to be excellent. But absolute position – basically the origin of the co-ordinate system – can be out.

The bottom line is if you are trying to calculate position with a sextant and clock, it’s hard enough in good conditions (for me!). But in a snowstorm when it has been overcast for several days? The historical navigators are my heroes.

In practice today does this lack of accuracy matter?

Charcot Island. A photograph of a repeater of the navigation display of RRS James Clark Ross in 2008.

That picture of the ship’s track tells the story. The ship has skirted the coast of the island, but according to the chart we ended up on land! I have a few examples like this from Antarctica. And even the mighty Google Earth has Charcot Island wrong.

A screengrab of Charcot Island from Google Earth Pro 20 Nov 2016. The island is displaced by ~11 nautical miles.

Polar ship Captains, officers and crews take ships into areas that are genuinely unexplored. We don’t know the coastline or the water depths well.

In fact, in Antarctica all you really can be certain of is you know you are going to be surrounded by icebergs and sea ice.

It’s a big responsibility.

Today is 105 years since Roald Amundsen, Helmer Hanssen, Sverre Hassel, Oscar Wisting and  Olav Bjaaland reached the South Pole. And Google have celebrated that fact with a google Doodle:

Amundsen expedition South Pole Google Doodle

I love the doodle. It’s beautiful art.

But it falls on me to be a bit of a bore…

The doodle shows mountains, and south pole is on an extremely flat plateau. Amundsen named it the King Haakon VII’s Plateau.

The doodle shows it’s snowing quite heavily. Actually South Pole is technically a desert, and almost no snow falls. The snow does drift in the winds though.

The doodle shows it’s dark… The sun comes above the horizon at South Pole in September and it doesn’t set until March. When Amundsen and the team arrived it would have been 24 hour daylight.

They have the black flag just perfect though. Although Amundsen actually had a white flag and the Norwegian flag on his tent, they did use black flags to survey the region and check they were at the actual South Pole.

Members of Roald Amundsen’s South Pole expedition 1910-12 at the pole itself, December 1911, (from left to right): Roald Amundsen, Helmer Hanssen, Sverre Hassel and Oscar Wisting. Source Wikipedia.

I took a picture of one Amundsen’s pole flags at the Scott Polar Museum a few years ago. It was found with Scott, Bowers, and Wilson bodies in  November 1912. Beneath the flag you can see the image Edward Wilson drew in his notebook of the flag.

Today there is an amazing research station at the South Pole called Amundsen-Scott, and there is a web cam on the United States Antarctic Program site.

Screen grab of the South Pole webcam on 14 December 2016.

It’s currently -26°C. That’s not so bad is it.

Susan Solomon’s book The Coldest March shows a plot on page 215 of my edition showing that is about the conditions Amundsen and his team had to deal with.

Mark Brandon • March 7, 2017

The polynya I saw forming in early February is still clear, and very large in the Southern Weddell Sea. At the moment it is more than than 80,000 km², although there is clearly a lot of young sea ice covering a large part of the polynya.

The Weddell Sea 5 March 2017 in the Terra MODIS true colour image.

In my original post I said this was likely formed by winds from the Ronne Ice Shelf.

Well Dr Stef Lhermitte (Delft) has put together the most amazing movie showing the development of the polynya over January and February. It shows satellite sea ice data with winds from the ECMWF overlain.

You can clearly see the winds pushing the sea ice away from the ice shelf as time progresses.

It is just as @StefLhermitte said in his tweet yesterday:

…continue reading →

Posted in Science. Tags: A23, A23a, antarctica, ECMWF, Larsen C, polynya, Ronne Polynya, Stef Lhermitte, Weddell Sea on March 7, 2017 by Mark Brandon.