Uncertainty analysis and risk analysis are two important areas of modern water resource management,in which accurate variance estimation is required.The traditional runoff model is established under the assumption tha...Uncertainty analysis and risk analysis are two important areas of modern water resource management,in which accurate variance estimation is required.The traditional runoff model is established under the assumption that the variance is a constant or it changes with the seasons.However,hydrological processes in the real world are often heteroscedastic,which can be tested by McLeod-Li test and Engle Lagrange multiplier test.In such cases,the GARCH model of hydrological processes is established in this article.First,the seasonal factors in the sequence are removed.Second,the traditional ARMA model is established.Then,the GARCH model is used to correct the residual.At last,the daily runoff data in 1949-2001 of Yichang Hydrological Station is taken to be an example.The result shows that compared to the traditional ARMA model,the GARCH model has the ability to predict more accurate confidence intervals under the same confidence level.展开更多
Urban green land compensation plays an impor-tant role in county development,ecological environment management and many other fields.The concept,methods and principles of urban green land are introduced in this paper....Urban green land compensation plays an impor-tant role in county development,ecological environment management and many other fields.The concept,methods and principles of urban green land are introduced in this paper.According to the pay fee method,the value and ecological function of various types of urban green land were analyzed.The cost-benefit analysis method(CBAM)was used to estimate different external diseconomy benefits caused by green land loss.The authors applied CBAM to estimate such benefits in the case of Shanghai,China,and calculated the actual compensation value for green land.Results indicated that in 2002,the compensation value for the green land of Shanghai was RMB 8.58×10^(5) Yuan/hm^(2).展开更多
基金supported by the National Hi-Tech Research and Development Program of China ("863" Project) (Grant No. 2012BAB02B04)
文摘Uncertainty analysis and risk analysis are two important areas of modern water resource management,in which accurate variance estimation is required.The traditional runoff model is established under the assumption that the variance is a constant or it changes with the seasons.However,hydrological processes in the real world are often heteroscedastic,which can be tested by McLeod-Li test and Engle Lagrange multiplier test.In such cases,the GARCH model of hydrological processes is established in this article.First,the seasonal factors in the sequence are removed.Second,the traditional ARMA model is established.Then,the GARCH model is used to correct the residual.At last,the daily runoff data in 1949-2001 of Yichang Hydrological Station is taken to be an example.The result shows that compared to the traditional ARMA model,the GARCH model has the ability to predict more accurate confidence intervals under the same confidence level.
基金This work was supported by the National Natural Science Foundation of China(Grant No.50579003).
文摘Urban green land compensation plays an impor-tant role in county development,ecological environment management and many other fields.The concept,methods and principles of urban green land are introduced in this paper.According to the pay fee method,the value and ecological function of various types of urban green land were analyzed.The cost-benefit analysis method(CBAM)was used to estimate different external diseconomy benefits caused by green land loss.The authors applied CBAM to estimate such benefits in the case of Shanghai,China,and calculated the actual compensation value for green land.Results indicated that in 2002,the compensation value for the green land of Shanghai was RMB 8.58×10^(5) Yuan/hm^(2).
