| Runoff changes influence the development of social economy in a basin,the study of runoff change has always been hydrologists problem of concern,the present study mainly has two aspects: one is the quantitative analysis of the contribution of human activities and climate change on runoff change size,secondly,in view of the change of the runoff time series,how to accurately and effectively predict a basin the size of the runoff in the future.Quantitative study of the impact of climate change and human activities on runoff and the main factors leading to runoff change is of great significance to the sustainable management of water resources in the basin.At the same time,it can make an effective and accurate prediction of runoff forecast and provide a reference for the allocation of water resources in the basin.In this paper,based on the hydrometeorological data of Changshui hydrology station in Luohe river basin sequence from 1961 to 2016,the moving average method is used,Mann Kendall nonparametric statistical tests and R/S analysis method has carried on the trend analysis,applying the Mann-Kendall mutation approach,mutation accumulation curve method is used for testing,then the contribution rate of runoff from human activities and climate change was quantitatively distinguished by the comparison of cumulative slope change rate.Finally,ridge regression analysis model and R/S gray combination model were used to study and analyze the runoff prediction of Changshui hydrographic station in Luohe River basin.The conclusion is as follows:(1)The results of trend analysis show that the annual precipitation of Luohe River basin during 1961-2016 shows no significant decline trend,and has a weak continuous decline trend in the future.The evaporation and annual runoff showed a significant downward trend for a period of time in the future.And the average annual temperature showed a significant upward trend and will continue to rise in the future.The results of abrupt change analysis show that the temperature abrupt change occurred in 1998.Evaporation mutation point in 1999;The annual precipitation is divided into several abrupt change points in 1966,1968,1973,1977,1985 and 1989 respectively,and the abrupt change point of annual precipitation is 1977.(2)The research on the contribution rate of climate change and human activities to the runoff of Luohe River basin shows that the cumulative anomaly method is used to identify the abrupt change years in the annual runoff and annual precipitation change process.Based on the cumulative change rate comparison method,the base period 1961-1985 and the abrupt period 1985-2016 were taken as the abrupt period.During the abrupt period,the contribution rate of human activities to the runoff reduction was 57.08%,the contribution rate of precipitation to the runoff reduction was 15.85%,and the contribution rate of evaporation to the low runoff was 27.07%.Finally,it is concluded that human activity is the main factor affecting runoff.(3)Based on ridge regression analysis model of Changshui hydrographic station of Luohe River basin runoff forecast results show that using ridge regression model with meteorological and hydrological data of 1961-2010 as analysis samples,the Luohe river basin runoff from 2011 to 2016 is forecasted,the results show that using ridge regression analysis model to predict the percent of pass is 50%,the prediction precision is low.Ridge regression analysis as a mathematical statistical method can be applied to runoff prediction,but the stability of prediction effect needs to be further improved.(4)Based on the R/S grey combination model of Changshui hydrographic station of Luohe River basin runoff forecast results show that using R/S grey combination model to forecast the results of 2011-2016 annual runoff accuracy reached 81.58%,and by a single gray theory model prediction accuracy is 53.83%,in river annual runoff prediction,R/S grey forecasting model is superior to the single grey model. |
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