Wind - The fuel for our expeditioners

Posted by Marc De Keyser- Polar Meteorologist greenland_katabatic_wind11

To cross a vast continent such as Greenland, our team depends almost completely upon Mother Nature. Adrian, Derek and Devon are excellent kiters. The combination of their skills, their kites/sails and the katabatic wind allow them to travel fast over the Greenlandic ice cap( please refer to previous blog from Adrian and the team)

Katabatic winds exist thanks to the huge piece of ice on top of Greenland. That ice cap is at places more than 3000 meter thick, which forms a vast plateau 3000 meter above the main sea level. The air mass on top of this plateau becomes extremely cold, and cold air is very dense, which means it is much heavier than the relatively warm air along the coasts of Greenland. Due to gravity the colder air starts rolling down from the high plateau towards the coast. This movement of cold air, which happens only in the lowest hundred meters of the atmosphere, is called ‘katabatic wind.’

The wind direction of the katabatic wind is, at one point, nearly always the same: it blows from the interior of Greenland to the coast and almost perpendicular on the elevation contours. The speed depends mainly on the angle of the slope, the steeper the slope the stronger the katabatic wind. At some places it is not exceptional that this wind blows with a speed of 40-60kt and this for several days in row.

Traditionally between 77 and 80° North winds are very slow. Because the slope between those latitudes is very weak, katabatic winds are rather slack or not present at all. That is why currently our three polar expeditioners are experiencing weak winds and are hardly making any progress.

Today and tomorrow there should be a westerly ‘kiteable’ wind. This could bring them North of 79 so there, the chances to catch a favorable katabatic are bigger.

So let’s pray to Aiolos, the Greek god of winds, that good winds may fill the kites of Derek, Devon and Adrian.

 

(www.weather4expeditions.com)

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