Tag Archives: Antarctic

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This just on twitter from the UK Ministry of Defence about the recent magnificent voyage of HMS Protector.

The Tweet posted by MOD on 18th Jan 2016
The Tweet posted by MOD on 18th Jan 2016

On the web page in the link it says

By visiting this region Protector achieved a latitude of 77 Degrees 56 Minutes South – the very edge of the vast Ross Ice Shelf, named for James Clark Ross who led the exploration of the area.

No official British ship has been this far south since 1936 and it is believed not since James Clark Ross’s own expedition in 1842.

I don't think this is true. The British Antarctic Survey Ship RRS Bransfield reached likely a little further south. According to this note from the Second Officer Chris Elliot which is published on the website The LOFTSMAN which is about the shipyards of Leith.

Furthest South of the RRS Bransield was 77 56' 44''
Furthest South of the RRS Bransield was 77 56' 44''

RRS Bransfield reached 77°56' 44"S.

So 44 seconds further south than HMS Protector.

Which is what? 1.3 km?

I know it's not much further south and Protector likely matched it (they don't give their decimal). I just wanted to make the point that it is close. Very close.

The second officer in the note - Chris Elliot went on to become the Captain of the RRS John Biscoe, and then he was a member of the team that built the RRS James Clark Ross for many years, before becoming one of the Captains of that great ship.

UPDATE See comment below by Radio Officer of the RRS James Clark Ross Mike Gloistein.

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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.

 

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I came across this brilliant Deep Sea News blog post about oil on troubled waters. It talks at length about how a surface film of oil damps out higher frequency surface waves and only the low frequency waves can propagate. The net effect is the sea feels calmer as the breaking waves are damped out.

The same thing happens in rough seas when ice forms. I took the picture below in Bellingshausen Sea.

A grease ice slick in the Bellingshausen Sea Antarctica
A grease ice slick in the Bellingshausen Sea Antarctica

What you are looking at is very thin slick made up of sea ice crystals in the open ocean (called grease ice). The layer of crystals only allows the low frequency waves to propagate - so you see these odd looking slowly propagating ripples.

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In March 2013 I was delighted to be asked to give a talk at TEDx Southampton.

This is what I talked about: What the poles are telling us about our world

It was brilliant to be asked to speak, and really enjoyed the fantastically well organized day. Many thanks to the hardworking large team who put it together, and in particularly James Dyke,Alison Simmance and Jonathan Akass.

On the TEDx Southampton YouTube channel for the event are some amazing talks from that day.

 

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It's a little odd to me when people refer to the polar regions as being something to do with the "sounds of silence". I have never thought of peace and quiet when I am on sea ice. You see the sea ice is always moving, (except when it is frozen to the coast and then we term it "fast ice"), and when it moves - the individual floes are constantly colliding and banging into each other. The collisions and banging can be very noisy.

Samuel Taylor Coleridge knew that when he wrote the The Rime of the Ancient Mariner in 1798.

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[This is a post bringing together things I have done elsewhere whilst learning how to use this platform.]

I am a huge fan of the Natural Environment Research Council, and used to work for the British Antarctic Survey. It is a fact that in the UK at the moment the community has some very tough funding decisions to make.

NERC decided to investigate  saving money through a possible merger of the National Oceanography Centre and BAS.  It is fair to say that  this was not so well recieved.

Observer news story
The story in the Observer

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