ABSTRACT
Thefactorsgoverningevaporationfromopenwaterandfromavegetated surfacearedescribedinChapter4.Inthatchapter,methodsofmeasurement ofwaterlossesareoutlined.Thepracticalapproachofthosemethods considerstheevaporationprocessfromtheliquidphaseasthelossratefrom thewaterbodywiththefinalmeasurementsbeinggivenintheformofan equivalentdepthofwaterlostoveraselectedtimeperiod.Theevaluationof evaporationintothegaseousphaseconsidersthegainofwatervapourbythe airabovetheopenwaterorvegetation,i.e.theabsorptionofthewater vapourbytheairmeasuredoveraperiodoftime.Theinstrumentation requiredtomeasuretherelevantpropertiesoftheairisdescribedinthat earlierchapter.Heretherelatedanalysisandcomputationsusingthe measuredmeteorologicalvariablesaresetout.
