Survey of Temporal and Special Changes of Nisan Rainfalls and Prediction of Them in East Azarbayjan Province

Abstract

In this paper, Nisan rainfalls of East Azerbaijan Province in the period of 1980 to 2009 were investigated. Initially changes of Nisan rainfalls trend were analyzed using the non-parametric Mann-Kendall test and Sen's estimator slope that are the most common methods of non-parametric tests. In order to predict changes of Nisan rainfalls in the next years, ARMA time series model was used. The results indicated that according to non-parametric tests in the study period, time series of Nisan rainfalls have no trend in none of the stations except Azarshahr. After reviewing of different patterns of ARMA model, proportional model for each station was selected based on Akaike information criterion (ACI) and, the Nisan rainfalls in East Azerbaijan Province were predicted for next 10 years. The accuracy of models was confirmed based on normality tests for residuals of the model and RMSE

Keywords

• nisan rainfalls
• trend
• mann-kenedall
• prediction
• arma model
• east azerbaijan