تحليل مقدماتي سري هاي زماني تراز سطح آب درياچه ي اروميه

Preliminary Analysis of the Time Series of Urmia Lake Water Elevation

The frequent occurrence of drought and high evaporation of water resources on one hand the execution of dam projects on the rivers flowing into the lake and exploiting the surface water on the other hand has caused great reduction in the amount of water volume and the area covered by it during recent decades, resulting significant changes in the coastal lines. This has resulted in extra salinity of the water to leave undesired impact on vulnerable ecological system. Regarding the impact of such process, the main aim of this article is to provide a graphical description of different water elevation data through derived indicators of time series. To reach a goal the daily records of water elevation from 1970 to 2004 existing at Golmankhaneh station were used and analysed. To create time series in seasonal and annual scale, Excel software and Mini Tab have been used. For preliminary analysis of time series, firstly the primary indexes like observation smoothed data; moving average and percentage of fluctuation have been illustrated through graphic models. Secondly other factors like observed seasonal and irregular cycle have been calculated and simulated, and thirdly normalized remain mass curve techniques are used to detect the fluctuations in lake water elevation. Final findings indicate magnificent fluctuations in Urmia lake water elevation.