Raindrops

Listening to the rhythm of the falling rain is one of life’s simple pleasures—and an inspiration for music, poetry, and much more. And in recent years, it’s become a source of knowledge for scientists who study our changing climate. They’re listening to the rain as it falls on the ocean, providing a more complete picture of Earth’s water cycle.

Water evaporates from the ocean surface. It forms clouds, which produce rainfall over land or other parts of the ocean. This cycle can be changed by Earth’s warming climate. Understanding just how it changes requires a detailed knowledge of ocean rainfall—where, how much, and how fast.

But there aren’t many rain gauges in the open ocean, so rainfall is hard to track. Satellites provide some help, but they can’t see the entire ocean surface at once. So scientists have started listening to the rain. That reveals where the rain is falling, and the length of each storm or shower. It also reveals the intensity of the rain, because different rainfall rates and raindrop sizes produce their own distinctive sounds.

Scientists have placed microphones on existing instrument packages. Some of them are anchored to the ocean floor. Others bob up and down through the water column, sampling conditions from the surface down to thousands of feet. Test runs have provided good results. So there are plans to expand the research to thousands of platforms—listening to the patter of raindrops throughout the world’s oceans.