An accumulated thermal unit, is a unit of measurement used to describe the cumulative effect of
temperature
Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer.
Thermometers are calibrated in various temperature scales that historically have relied o ...
over time. 1 ATU is equal to 1
degree Celsius for 1 day. For example, in an environment at a constant temperature of 5 °C, 5 ATU would accumulate per day, with 65 ATUs accumulated after 13 days.
Accumulated thermal units are used, for example, in
aquaculture
Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants (e.g. lot ...
to track the development of incubating
salmonid eggs. Eggs incubated at 10 °C develop twice as fast as eggs incubated at 5 °C.
{{measurement-stub
Standards
Temperature