Abstract
Relative humidity affects evaporation, whichisin turn is affected by several climatic parameters. This effect is on the increaseas a result of climate changes, especially increasedtemperature.Nabatiyeh region, insouth Lebanon, was selected for this study, even thoughcomprehensive climaterecords are not available. Instead, data from an experimentalmeteorological station capable of providing all climatic parameters digitally, which includes an evaporation basin of the form A, was used.This study providedexplanations of the general climate in the study area.This includesaverage annual temperature, precipitation and evaporation. Factors affecting relative humiditywere determined.It was found that theevaporationvalueschanged by thechangingdirection of the prevailing wind,andfluctuating higher valueswere recorded in autumn, due to the south-eastern dry winds, which lead to a fluctuation in the amount of daily evaporation.An inverse relationship between relative humidity and evaporationwas observed, with significant correlation between them. The net effect of relative humidity onevaporationwas investigated in this studyby comparing data in two days in which the values of other climatic factors affecting evaporation were the same. It was found that the amount of daily evaporation increased by 80% when the relative humidity declined to 53%.Most likely, in the coming years, the region is moving towards more water stress in light of changes in climatic parameters.
