Friday, July 1, 2011


- Brett Stacy [Humboldt State University]

When one imagines the open ocean, they may picture it as a constantly dynamic and often ferocious landscape. With huge crashing waves, high speed winds, and ship-dwarfing storms. Even looking at the background to this blog gives a viewer that impression. One of the many goals of this cruise is to document one of these features of the ocean, moreover the effect of one of these features on the state of the sea surface: The wind and the white caps they induce.

White caps hold special significance to our world. Besides being a surfer’s worst enemy and a kite-surfer’s best friend, white caps have a profound influence on, you guessed it, climate change. They contribute to gas exchange between the ocean and atmosphere, they affect the reflectivity of solar radiation reaching the earth’s surface, and they serve as a visual byproduct of the transfer of energy from wind to ocean surface currents.

Throughout this cruise, my job is to quantify the proportion of white caps covering the sea surface in order to later relate their influence on relative flux measurements between and DMS made by others on the ship. How do I do this? Using state of the art cameras mounted on the highest point of the ship, images of the sea surface and the white caps on it are automatically collected once every second during the daylight period. These images are then processed to discover what proportion of their contents include white caps. The process includes converting the image to black and white, with a threshold for the color white determined by observation of the color characteristically exclusive to white caps. The final result is a White Cap Fraction (WCF) for each image.

Being the ocean’s personal photographer has been a blast. Participating on the Knorr in general has been great. This cruise is my first time on a significant (more than one day) research voyage and so far it’s been an adventure. Every day something interesting happens and new challenges arise bringing everyone on the ship closer together. It has only been one week on the Knorr since leaving Woods Hole, but already it feels like we are all part of a big family. Every ones’ positivity and enthusiasm makes life at sea fun and easy-going. I can’t wait to see how our family develops and what exciting events are in store for us at higher latitudes!

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