precipitation-evaporation ratio

precipitation-evaporation ratio

[prə‚sip·ə′tā·shən i‚vap·ə′rā·shən ‚rā·shō]
(climatology)
For a given locality and month, an empirical expression devised for the purpose of classifying climates numerically on the basis of precipitation and evaporation. Abbreviated P-E ratio. Also known as precipitation effectiveness.