H. R. Ghazvinian, H. Karami, Y. Dadrasajirlou,
Volume 28, Issue 2 (Summer 2024)
One method used to estimate the evaporation rate involves employing various types of evaporation pans, including the standard Colorado Sunken and Class A evaporation pans. This study aimed to investigate and compare the evaporation rates from two pans, Class A and Colorado Sunken, in Semnan City. The Colorado Sunken evaporation pan was utilized as the test pan, and the test was conducted in an open space near the Faculty of Civil Engineering at Semnan University, located in Semnan City. Evaporation measurements were recorded daily for 123 days, from June 1, 2017, to September 31, 2017. The evaporation amount from the Class A pan was obtained from the synoptic station of Semnan city, situated 2.39 km away from the test site, and was subsequently analyzed. Meteorological data, including maximum and minimum temperature, maximum and minimum relative humidity, wind speed, sunshine hours, and air pressure, were also collected from the Semnan synoptic station and compared with the experimental evaporation data. The results indicated no significant difference in the daily evaporation amount between the Class A pan and the Colorado Sunken pan during the tested periods. The best statistical distribution, based on Kolmogorov–Smirnov test, for the Class A evaporation pan and the buried Colorado pan, were selected as Error with (k-s=0.05019) and Gamma with (k-s=0.05552). The coefficient of determination between the two pans was estimated to be approximately 93%. Further analysis revealed that the rate of evaporation is most closely associated with the maximum daily temperature. Pearson's correlation coefficient for the maximum temperature with the Class A evaporation pan and the Colorado Sunken pan was found to be 0.623 and 0.647, respectively.
