Between September 26 and October 7, 2016 The Ocean Cleanup conducted a series of reconnaissance flights across the Great Pacific Garbage Patch: the Aerial Expedition. The objective of the mission is to accurately quantify the ocean’s biggest and most harmful debris - discarded fishing gear, called ghost nets. How much of this very large debris can be found in the ocean is the last remaining piece of our puzzle to understand how much ocean plastic is there to clean up.
MAPPING PLASTIC FROM THE SKY
In order to be able to clean up the Great Pacific Garbage Patch, it is essential to understand its dimensions. Knowing how much and what kind of plastic it contains is especially important. It determines the design of cleanup systems, the logistics of hauling plastic back to shore, the methods to recycle the plastic, and the cleanup’s economics.
We started answering this question last year, when we launched the Mega Expedition. With a fleet of about 30 vessels, we produced the first high-resolution map of the infamous plastic accumulation zone, situated halfway between Hawaii and California.
Conventionally, ocean plastic is quantified using small, one meter-wide trawls, which means only a very small portion of the size spectrum was measured. The larger pieces of plastic become, the rarer (by count) they become, so a larger area needs to be covered to accurately quantify large debris. Hence, during the 2015 Mega Expedition, we used very large nets to also be able to measure larger pieces of plastic. This was successful for debris of up to about a meter in size, but we know ocean garbage can be much larger than that. Enter: the Aerial Expedition.
Ocean Force One
The aim of the Aerial Expedition was to accurately measure the biggest and most harmful debris in the ocean. We believed this could be achieved by covering an area even larger than was done during the Mega Expedition. This was the first-ever aerial survey of an ocean garbage patch. The Aerial Expedition’s results will be combined with the data we collected on the Mega Expedition, resulting in a study we expect to publish in early 2017.
HOW WE DID IT?
With a flight crew of 10 researchers, 3 sensor technicians and 7 navigation personnel, The Ocean Cleanup’s Aerial Expedition used a combination of experienced human observers and advanced sensors to count the debris. The C-130 Hercules aircraft, named Ocean Force One (following a Twitter suggestion), flew at a low speed (140 knots) and low altitude (400m) while mapping the area. Advanced sensors helped convert the count from the visual survey to a weight estimate by registering the size of the objects detected.
A selection of large objects observed in the Great Pacific Garbage Patch during the Aerial Expedition
All this will help us develop our cleanup technology, of which the pilot is scheduled to be deployed in 2017.
Relive the Aerial Expedition - Aftermovie