عنوان مقاله [English]
Â Lake Urmia, the third hyper-saline lake in the world and because of its climatic, economic, social and ecological/environmental importance is a populated region in Iran. Recently, severe drought periods and low water levels are causing problems in this lake. Therefore, it is urgent and desirable to evaluate Urmia water level fluctuations in a scientific ways. Urmia lake water level the same as other great lakes have fluctuated over years which it can be taken as a classic tale in sun/climate relationship in Iran. For this reason we examined water level fluctuations and its candidate predictor variables from 1965 to 2006 years for investigation the changes in long-term and detect its relationship with sunspot activity. Also, the Continuous Wavelet Transform and Cross Wavelet were used to analysis and predict water level fluctuations. Hence, we have found that the Urmia lake level and sunspot activity shown most significant periodicities around 8-11 yr. Cross wavelet analysis showed that: Urmia lake level fluctuations have a higher power around the 8-11 solar cycle periods. So these two variables are correlated at 8-11 yr, but this correlation is reverse or negative. Results from analyzing the Urmia lake candidate predictor variable's also support such effects. Finally, we concluded that the most important natural phenomenon that effects Urmia lake level fluctuations is solar activity.