RADAR is an acronym
RAdio Detection And Ranging, a US Navy coinage from 1940, and how it changed storm watching.
The letters
RADAR = RAdio Detection And Ranging. The US Navy coined it in 1940. It's an acronym that became an ordinary word, and it happens to be a palindrome: it reads the same backwards, fitting for a signal that goes out and bounces back.
How it works
Send out a pulse of radio waves. When it hits something (a plane, a ship, raindrops), part of it bounces back. The time it takes to return tells you how far away the object is (the "ranging"). The direction the antenna was pointing tells you where.
Why it matters for storms
Radar was built for war, to spot aircraft and ships, but World War II operators noticed rain cluttering their screens. After the war that "clutter" became the point: weather radar lets forecasters see a hurricane's rain bands and eye as it approaches the coast. Before radar, and long before satellites, forecasters had only what people could see and measure on the ground and the reports the telegraph carried. See the telegraph and storm warnings.
Key facts
- RADAR: RAdio Detection And Ranging (US Navy, 1940)
- Radar measures distance by the echo's return time
- Rain "clutter" on wartime radar became weather radar