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url: https://www.eurocovers.eu/glossary/pan-evaporation
term: Pan evaporation rate
definition: Direct measurement of evaporation from a standardised water pan (US Class A pan or European equivalents). Higher than reference evapotranspiration (ET0) by 1.0–1.4×.
updated: 2026-05-25
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# Pan evaporation rate

Direct measurement of evaporation from a standardised water pan (US Class A pan or European equivalents). Higher than reference evapotranspiration (ET0) by 1.0–1.4×.

**Pan evaporation** is the directly measured evaporation from a standardised water pan — the US
Class A pan or European equivalents. Pan rates exceed reference evapotranspiration (ET0) by
approximately 1.0–1.4× depending on climate and exposure. For industrial reservoir water management,
pan evaporation is a better predictor of open-water loss than ET0 alone. Floating covers reduce
the effective pan rate at the covered area by 90–97%.