Archive for April 14th, 2010

Amelia & Kyle take the wheel

Wednesday, April 14th, 2010

A new glider, a new class, and two new pilots take the controls. Amelia & Kyle set their first waypoint this morning. Here is what we did.

First John shifted the Colorado altimetry window 2 degrees north. We typically capture an 8 degree of Latitude swath of altimetry data from the Colorado server. Because the Colorado surface current maps are generated on a different projection than google earth, a wider north-south band is more difficult to project onto the google earth globe. So we like to keep it narrow in this direction. East-west matters little - it can be almost any length in this direction.


The most striking feature for us is the relatively continuous current that runs to the east along 26.5 N. I've highlighted the current it with a red line. The task for this semester's class is to get the glider Cook up to the 26.5 N latitude by the end of the spring semester. The summer class will pick up from there and hopefully fly us in close to the Canaries. Then the fall class takes over and flies us somewhere else.

The blue path north is the path we choose last week. The blue path was designed to fly the glider between the two counterclockwise eddies in located between 22N and 23 N. They are in yellow, so they are relative lows in sea surface height, just like low pressure storms in the atmosphere. Note how the circulation around the relative highs in red are clockwise, the opposite of the circulation around the lows. But this week it looks like these two counterclockwise, low sea surface height eddies have merged, and there is no current to ride north along the blue path. Then the blue path runs into a head-current about until it reaches the favorable currents at 25 N associated with one of the clockwise eddies. So Amelia and Kyle looked for an alternate route north. They filled in the green path. Its a slight shift to the west, taking us through the quieter parts of the yellow eddies, avoiding the head current between 23.5 N and 25 N, and getting us to the meandering current at about 25 N, 62.5 W. That will bring us up to 26.5 N.