Definition
A measure of the intensity of atmospheric turbulence, expressed as the rate at which small-scale swirling air motions (eddies) lose their energy to heat through friction. It is reported in units of cubic meters per second cubed raised to the one-third power, and is the international standard for objectively quantifying turbulence experienced by an aircraft, independent of aircraft type or weight.
Plain English
A number that tells you how rough the air is. The higher the number, the bumpier the ride, regardless of what aircraft you are flying.
Context Anchor
Seen in aviation weather products, turbulence forecasts, and automated turbulence reports from aircraft.
Derivation
An eddy is a small swirl of moving air or water — the same word used for swirls in a stream. To dissipate means to break up and fade away. The rate is how fast that breaking-up happens. Together: how quickly the swirling motion in the air burns off into heat. Faster burn-off means more energetic swirls, which means rougher air for the aircraft passing through.
Why Pilots Care
Accurate EDR values let pilots anticipate turbulence intensity, choose safer altitudes, and reduce the chance of injury or discomfort.
Analogy
Think of stirring cream into coffee. At first there are strong swirls; then the swirls break down and fade. Eddy Dissipation Rate is about how actively those swirls are breaking down in the air.
Grounding Statement
In rough air, the atmosphere contains many small, uneven motions, and Eddy Dissipation Rate is one way to measure how strong that uneven motion is.
Intuition Check
Eddy Dissipation Rate is not simply wind speed. Fast smooth wind can have low turbulence, while slower air with strong uneven swirls can have a higher Eddy Dissipation Rate.
Example Sentence 1
The dispatcher rerouted the flight after the forecast showed a high Eddy Dissipation Rate along the planned track over the mountains.
Example Sentence 2
The aircraft automatically transmitted an Eddy Dissipation Rate value of 0.35 during cruise, alerting air traffic control to moderate turbulence ahead.