Comparison between simplified and standardized Penman evaporation equation: Egyptian Mediterranean coast case study

Abstract

One of the dilemmas that researchers face when applying the Penman equation (1948) is that it requires significant meteorological data that are not readily available at the standard meteorological stations. Therefore, many researchers have worked hard to devise several simplified algebraic equations that are equivalent to the standard Penman equation to calculate evaporation quantities with accuracy from the available data. In this study, the Penman equation, which is a reference method, was applied in addition to four other simplified methods. Notably, one method of the simplified methods did not require wind speed data. To calculate the evaporation quantities by analyzing the daily averages along the Egyptian Mediterranean Coast (Mersa Matruh, Alexandria and Port Said) for a period of ten years from 2007 to 2016, several statistical methods have been applied to assess and evaluate the performance and suitability of these simplified methods. It was clear from the results obtained that two of these simplified methods are of good efficiency when compared to the standard Penman equation, whereas, the third method is only valid for moderate or low wind speeds (< = 3 m/s). The results of the fourth method indicated that it was not suitable for application in the study area.