Sunday, October 5, 2014

ESA CryoSat-2 and Jason-1 Satellites detect 'thousands' of new ocean-bottom mountains

ESA CryoSat-2 and NASA's Jason-1 satellites capture new gravity data.

ESA's CryoSat-2 and NASA's Jason-1 satellites capture new gravity data gives us our clearest view yet of the shape of the ocean floor

It is not every day you can announce the discovery of thousands of new mountains on Earth, but that is what a US-European research team has done.

What is more, these peaks are all at least 1.5km high.

ESA's CryoSat-2 Earth Observation satellite.

Credit: ESA

The reason they have gone unrecognised until now is because they are at the bottom of the ocean.

Prof Dave Sandwell (UCSD) and colleagues used Cryosat-2 and Jason-1 radar satellites to discern the mountains' presence under water and report their findings in Science Magazine.

"In the previous radar dataset we could see everything taller than 2km, and there were 5,000 seamounts," Prof Sandwell told reporters.

"With our new dataset, and we haven't fully done the work yet, I'm guessing we can see things that are 1.5km tall.

"That might not sound like a huge improvement but the number of seamounts goes up exponentially with decreasing size.

"So, we may be able to detect another 25,000 on top of the 5,000 already known," the Scripps Institution of Oceanography researcher explained.

The new detailed map of the sea floor is available here.

Knowing where the seamounts are is important for fisheries management and conservation, because it is around these topographic highs that wildlife tends to congregate.

The roughness of the seafloor is important also as it steers currents and promotes mixing, behaviours that are critical to understanding how the oceans transport heat and influence the climate.

But our knowledge of the seafloor is poor; witness the problems they have had searching for the missing Malaysia Airlines jet MH370, which is believed to have crashed west of Australia.

Seeing fracture zones tells scientists about the movement of the continents
The problem is that saltwater is opaque to all the standard techniques that are used to map mountains on land.

Ship-borne echosounders can gather very high-resolution information by bouncing sound off bottom structures, but less than 10% of the global oceans have been properly surveyed in this way because of the effort it involves.

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