Remote Islands, part II: Tristan da Cunha

Are you tired of 100 °F heat? We sure are in Colorado. Denver tied an all-time record of five consecutive days of 100+ °F high temperatures this week (two of which had the all-time highest recorded temperature of 105 °F). Much of the country experienced record-breaking heat as well. What better place to escape the heat than to visit the Islands of Refreshment?

The islands were given the name by a group of four Americans who sailed there in 1810, intending to make it their own kingdom. Unfortunately, 75% of them died in a boating accident less than two years after they arrived. I suppose, if the fourth one died we never would have heard this story. To the rest of the world, the islands were and are known as Tristan da Cunha, named after Tristão da Cunha – the Portuguese explorer who first found them in 1506.

It’s hard to get more remote than Tristan da Cunha. The four main islands, Tristan da Cunha, Inaccessible Island, Nightingale Island and Gough Island are part of the British Overseas Territory of Saint Helena, Ascension and Tristan da Cunha. The only way to visit them is by boat from South Africa – which takes a week – and boats only come around once or twice a month. You also need to write a proposal to the Secretary of the Administrator outlining what you plan to do there in order to gain permission to visit. The permanent population of the islands is less than 300, and they’ve even developed their own version of English. Another interesting fact: they only acquired television in the last 10 years (according to Wikipedia).

So where is Tristan da Cunha? The small island territory is 2,816 km from the nearest continent (Africa) and 2,430 km from their administrative capital (St. Helena). Let’s see if you can find it in high-resolution visible (I-01, 0.64 µm) imagery from VIIRS:

Visible image (I-01) of Tristan da Cunha from VIIRS, taken 14:49 UTC 25 June 2012

Visible image (I-01) of Tristan da Cunha from VIIRS, taken 14:49 UTC 25 June 2012

Give up? I’ll make it easier and show the false color RGB composite (I-01, I-02 and I-03):

False color RGB composite of VIIRS channels I-01, I-02 and I-03 taken 14:49 UTC, 25 June 2012

False color RGB composite of VIIRS channels I-01, I-02 and I-03 taken 14:49 UTC, 25 June 2012

Three of the islands are easy to pick out now, particularly if you click to get the full size image. (Click on the image, then click on the 1512×1226 link below the banner.) The fourth island is difficult to see as it is covered by clouds and ice and snow, which look like clouds.

Here they are, labelled:

False color RGB composite of VIIRS channels I-01, I-02 and I-03 taken 14:49 UTC, 25 June 2012

False color RGB composite of VIIRS channels I-01, I-02 and I-03 taken 14:49 UTC, 25 June 2012

Nightingale Island, at 3.2 km2, is only about 5×4 pixels in size! The volcano that makes up the main island, Queen Mary’s Peak, rises 6,765 ft. above sea level and is casting a “cloud shadow” (i.e. no clouds are seen immediately downwind, or northeast, of the island). There may even be a von Kármán vortex behind it. Gough Island is also casting a “cloud shadow”, although it is much smaller.

If you really zoom in, you can almost convince yourself that VIIRS can identify two much smaller islands off the northern tip of Nightingale Island, Middle Island and Stoltenhoff Island:

False color RGB composite of VIIRS channels I-01, I-02 and I-03 taken 14:49 UTC, 25 June 2012

False color RGB composite of VIIRS channels I-01, I-02 and I-03 taken 14:49 UTC, 25 June 2012

Look for the two greenish pixels above Nightingale Island. These islands are both about 25 acres in size (0.1 km2).

While the only town, Edinburgh of the Seven Seas, is on Tristan da Cunha, there is also a year-round research facility on Gough Island. There are three meteorologist positions on the island, as it is an important weather station for South Africa and the United Kingdom. As a bonus, the record high temperature has never come close to 100 °F. So, if you’re really looking to get away from the heat (and everything else), Gough Island might be the place for you!

Leave a Reply

Your email address will not be published. Required fields are marked *


1 × eight =

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>