Tag Archives: ship

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

Screen Grab of the BBC News WWW site story.
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.
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.
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.
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).
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).
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.
Tweet from Dr Stefan Hendricks.

**** Update 2 from Twitter

From Dr Ruth Mottram at the Danish Meteorological Institute.

Tweet from Dr Ruth Mottram
Tweet from Dr Ruth Mottram.

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
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
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.
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.
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.