Investigate the Possibility Estimating Evaporation Using El Nino in Khoramabad Synoptic Station

El Nino is a climate phenomenon that affect many in climate variables in the parts of the earth. Due to the evaporation Role of water Study, the El Nino effect on climate parameters, will be important. In this study, using data from the El Nino and with the help of artificial neural networks to estimate evaporation in Khorramabad station has been studied. Monthly evaporation data in station for 29 years from 1992 to 2011 and El Nino data by the NOAA website provided and using artificial neural network analysis were investigated.The result indicate that from El Nino condition in Nina1 and Nina3 related with evaporation in station. By comparing the observed data evaporation and output neural network, data correlation is 78%. The correlation between El Nino and neural network output and the rate is 99 percent. Therefore, due to the high correlation between El Nino and output data network using the correlation equations can be used for months without data, to estimate the evaporation with 99 percent accuracy.