Scatterometer

A radar that sends microwave pulses to the surface and measures how much energy scatters back. Over the ocean, the roughness of the water — stirred up by wind — controls that return.

Why it matters

Scatterometers retrieve ocean surface wind speed and direction across the whole globe, day and night and through clouds, which is vital for weather forecasting, storm tracking, and ship routing.

Where you’ll meet it

• QuikSCAT carried the SeaWinds scatterometer that long set the standard for ocean wind mapping.
• ASCAT on the MetOp satellites provides operational ocean wind data used in forecasting.
• RapidScat, once mounted on the ISS, extended scatterometer wind measurements.

In plain terms

It’s like judging the wind by how choppy a lake looks — a calm mirror means no breeze, while a rough, rippled surface scatters the signal and signals strong wind.