Monthly Archives: June 2014

The ice fish rediscovered by Doll
Mangé par le chat de l'équipage de la Terror

The cod icefish re-discovered and published in 1904 by Louis Dollo. The original caption says “Mangé par le chat de l'équipage de la Terror” or “Eaten by the Terror’s cat"!

The famous polar ships HMS Erebus and HMS terror had been in the ice long before Franklin took them to their doom in the Northwest Passage. James Clark Ross took them to the Antarctic from 1839-43 on a hugely successful voyage to find the South Magnetic Pole. Ross filled in many blanks on the map and discovered and named many places including Ross Island and Mount Erebus - one of the most spectacular volcanoes yet discovered.

Ross also took civilian experts to describe and write about their discoveries. These civilians produced vast scientific volumes to record their results.

...continue reading

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-- UPDATED 11 June 2014 --

This post got the dreaded TL; DR on Reddit - but at least "they" acknowledged it was useful. Since it takes someone else to pick out the value in your work I offer this tweet from Jason Major.

@JPMajor tweet

- ORIGINAL POST

A significant area of Antarctic glaciological interest is the West Antarctic Ice Sheet (WAIS) and where it discharges into the Amundsen Sea Embayment.

Amundsen Sea Embayment
Amundsen Sea Embayment: Source Wikipedia

It is a research focus (e.g. iSTAR) because it is the region where the glacier ice is melting very rapidly.

A great research article by Dustin Schroeder (The University of Texas at Austin) has just been published in PNAS which presents evidence for the geothermal heat flux beneath the Thwaites Glacier.

Title page of Schroeder et al 2014

...continue reading

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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.