Application of Time-series Analysis Method on Groundwater Dynamic Variety on Changwu Tableland
Wenzhao Liu · DOAJ (DOAJ: Directory of Open Access Journals) · 2010
According to problem existed in water resource indigent on Changwu tableland,the time-series analysis theory is applied to analyze and simulate the dynamic variation of groundwater on Changwu tableland. First,the trend component of groundwater level dynamic variation is picked up by polynomial calibration,the periodic component is extracted by spectrum analysis and the stochastic component is simulated by using autoregression（AR） model. Then,a forecasting model is established through superposition of the three components. According to the month-average groundwater level data of the three wells in Changwu tableland,the dynamic simulating and forecasting model of groundwater level is established respectively by using index smooth model provided by SAS,and the accuracy of models is analyzed. The analysis of the application example shows that:（1） The time-series model is a simple simulation and forecast model of groundwater level because of simple computation and less demand of data. But the data should be continually updated in order to improve the accuracy of model; （2） But the data should be continually updated in order to improve the accuracy of model; （3） There is a major period in the variation of groundwater level in this area,including 7.4 years and 10 years cycle which becomes longer year by year,by which seasonal and secular variation of groundwater level is revealed; （4） The prediction for years after 2008 indicates that a continuing decline of groundwater level exists in this area,which must be controlled in time.