Rainfall is considered as one of the most difficult and complex elements of the
hydrological cycle, to understand and model, due to the complexity of air operations that
generate rain. The importance of research comes from the direct relationship b
etween the
rainfall amount and economic & social activities of the population, planning scopes of the
water resources management, particularly with respect to the agricultural development.
The research aims to highlight the rainfall amounts in Tartous station which is
located in the southern part of the Syrian coast, and applying one model of Box-Jenkins
models for the purpose of predicting future rainfall amounts. Multiple Arima models have
been tested. The results showed that the model SARIMA (3,0,4) was the best one. Data
were divided into 43 years to build the model and eight years to test it. The test results
gave high accuracy in the performance, and the model was used to predict the values of
annual rainfall for the next twenty years.
The study aims at comparing ARIMA models and the exponential
smoothing method in forecasting. This study also highlights the special
and basic concepts of ARIMA model and the exponential smoothing
method.
The comparison focuses on the ability
of both methods to forecast
the time series with a narrow range of one point to another and the time
series with a long range of one point to another, and also on the different
lengths of the forecasting periods. Currency exchange rates of Shekel to
American dollar were used to make this comparison in the period
between 25/1/2010 to 22/10/2016. In addition, weekly gold prices were
considered in the period between 10/1/2010 to 23/10/2016. RMSE
standard was used in order to compare between both methods. In this
study, the researcher came up with the conclusion that ARIMA models
give a better forecasting for the time series with a long range of one point
to another and for long term forecasting, but cannot produce a better
forecasting for time series with a narrow range of one point to another as
in currency exchange prices.
On the contrary, exponential smoothing method can give better
forecasting for Exchange Rates that has a narrow range of one point to
another for its time series, while it cannot give better forecasting for long
term forecasting periods