The magnitude of the hydrological frequency factor in maximum evaporation estimation for five stations in Iraq

الملخص EN

In this paper data of annual maximum evaporation and total annual evaporation (mm) from 1968 to 1993 years for Nasiriya, and Kirkuk stations, and from 1972 to 1993 years for Mosul, Amara, and Basra stations were analyzed by using frequency factor method for obtaining the magnitudes of extreme events.

The Extreme value type I (Gumbel) and Extreme value type II distributions were fitted to the annual maximum evaporation, and the Normal and Log Normal distributions were fitted to the total annual evaporation.

These distributions are used to fit evaporation data with 5, 10, 25, 50, 100 year return periods.

Return period and frequency factor relationships are obtained for all these distributions.

The study shows that Amara station had the maximum value of total evaporation (6634.24 mm) for 100 year return period by using Log Normal distribution, and there is an increase in evaporation amounts with the increase of return periods.