Caribbean Sea acts like a whistle and can be 'heard' from space

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A study of the Caribbean Sea by University of Liverpool ocean scientists has revealed that, in the midst of all the noise of the ocean, this region behaves like a whistle, which blows so loudly that it can be 'heard' from space in the form of oscillations of the Earth's gravity field.

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Researchers analysed the sea levels and pressure readings taken from the bottom of the Sea using four different models of ocean activity in the Sea over the period 1958 up to 2013 as well as using information from tide gauges and satellite measurements of gravity.

They noticed a phenomenon which they have called a 'Rossby Whistle' which happens when a Rossby wave -- a large wave which propagates slowly to the west in the ocean -- interacts with the seafloor.

This causes the wave to die out at the western boundary and reappear on the eastern side of the basin, an interaction which has been described as a 'Rossby wormhole'. Only waves of particular lengths can survive this process without cancelling themselves out, but these particular waves reinforce themselves, producing an oscillation with a sharply-defined period.

As a result, water sloshes in and out of the basin every 120 days. This mass change is sufficient to make changes to the Earth's gravity field which can be measured from satellites. The 120 day period means this whistle plays a note of A-flat, although it is many octaves below the audible range.

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