Tag: atmospheric circulation

Integrating Eyjafjallajökull

Second fissure, viewed from the north, on 2 April 2010 (from Wikipedia)

Current events often generate the teachable moments we’re always seeking in order to strike students’ imagination. The eruption of Eyjafjallajökull is a prime example. I’ve already used it to point out the intersection of geothermal energy and plate tectonics, but there is so much more.

The second eruption in Eyjafjallajökull. Seen from Fljótshlíð on 20 April 2010 (from Wikipedia).

Eyjafjallajökull has been a wonderful subject for the art of photography. The image above is a great example but the time-lapse photos have been excellent. The photo to the right captures not just the stars streaking across the sky with a three minute exposure but the fiery red arcs of the volcanic ejecta.

The MODIS instrument on NASA's Aqua satellite captured an ash plume from Eyjafjallajökull Volcano over the North Atlantic at 13:20 UTC on 17 April 2010 (from NASA via Wikipedia).

One of the major benefits of the space program so far has been its Earth observing satellites. There is so much going on in the image to the left that it’s hard to know where to start. Why are there all those clouds over Iceland? (warmer land mass creates convection); what’s with the two plumes from the volcano, one concentrated high level and one disperse low level plume; fjords on the upwind side of the island and the straightened coastline on the lee; greenish plumes of glacier-ground, rock flour discharging into the ocean.

Dust particles suspended in the atmosphere scatter light from the setting sun, generating 'volcanic lavenders' like this one over the flight path of Leeds-Bradford Airport in England during the aviation shutdown. (from Wikipedia).

The dinosaurs were done in either by an asteroid impact in the Yucatan or the eruption of the massive flood volcanoes in Deccan, India, or quite probably both. Both of these events launched an enormous amount of ash, gas and fine particles into the upper atmosphere, blocking sunlight, causing global cooling. Well the ash from Eyjafjallajökull and the sulfur dioxide gas may be having a similar effect on Europe, and if there’s enough of it, on the world. The 1992 eruption of Mt. Pinatubo cooled the globe by about half a degree Celsius.

A sailing game that explores the trans-Atlantic triangular trade

Discovering America

Wind patterns over the North Atlantic Ocean had a huge effect on the colonization and history of the Americas because, after all, all they had were sailing ships. The circular, clockwise winds meant that it was easiest to sail south and west from Europe, and when you did, the first place you arrived at in the New World was the Caribbean or the northern edge of South America. This helps explains the first settlements of the Portuguese and Spanish, and why the latecomers, like the British, ended up further north up the coast of North America.

Using wind data from the University Corporation for Atmospheric Research (UCAR) and Google Maps I created an online sailing game I call Mariner AO. The game is pretty simple (basic instructions are here), you tell your ship which direction to go, starting off near Lisbon in Portugal and sail the Atlantic. What makes it interesting is that you can go wherever you like and make your own objectives. All that limits where you can go is the fact that you can only sail within 90 degrees of the wind. It’s very Montessori in that you have choice within limits.

The game is most interesting, I think, if you set objectives like trying to sail the triangular trade route, Europe (Portugal) to Africa (Dakar) to America (Charleston) and back to Europe again. The general clockwise wind pattern is persistent throughout the year, but sometimes you need to wait until the wind changes to be able to reach your objective.

Alistair Boddy-Evans has a nice article on the triangular trade of European manufactured goods to Africa, African slaves to the Americas, and plantation crops back to Europe.

I really like this game because it integrates so much. Atmospheric circulation, slavery, colonization, and even the physics of sailing if you can and want to get into it. In fact, I think it’s enough to base an entire cycle of work around. I’m still taking comments about how to improve the game.