Water level prediction of river runoff is an important part of hydrological forecasting.The change of water level not only has the trend and seasonal characteristics,but also contains the noise factors.And the water l...Water level prediction of river runoff is an important part of hydrological forecasting.The change of water level not only has the trend and seasonal characteristics,but also contains the noise factors.And the water level prediction ability of a single model is limited.Since the traditional ARIMA(Autoregressive Integrated Moving Average)model is not accurate enough to predict nonlinear time series,and the WNN(Wavelet Neural Network)model requires a large training set,we proposed a new combined neural network prediction model which combines the WNN model with the ARIMA model on the basis of wavelet decomposition.The combined model fit the wavelet transform sequences whose frequency are high with the WNN,and the scale transform sequence which has low frequency is fitted by the ARIMA model,and then the prediction results of the above are reconstructed by wavelet transform.The daily average water level data of the Liuhe hydrological station in the Chu River Basin of Nanjing are used to forecast the average water level of one day ahead.The combined model is compared with other single models with MATLAB,and the experimental results show that the accuracy of the combined model is improved by 7%compared with the traditional wavelet network under the appropriate wavelet decomposition function and the combined model parameters.展开更多
Mineralisation is the result of the coupled multi-geodynamic processes in the crust. The coupled mechano-thermo-hydrological (MTH) processes are the basic physical processes that govern the location of the hydrotherma...Mineralisation is the result of the coupled multi-geodynamic processes in the crust. The coupled mechano-thermo-hydrological (MTH) processes are the basic physical processes that govern the location of the hydrothermal mineralization, which can be simulated in the computer by using of the numerical codes, such as FLAC. The numerical modeling results can be used not only to explain the features of existing ore deposits, but also to predict the favorable mineralization locations. This paper has summarized the basic equations describing coupled MHT processes in the water-saturated porous rocks, the principles of FLAC, and its application to the MHT processes related to copper mineralization in the Fenghuangshan ore field. We used the FLAC to simulate the syn-deformation cooling and fluid flowing evolution after the intrusion was emplaced and solidified. The modeling results suggest a most prospective exploration area where the subsequent exploration supported the prediction and the test bore hole disclosed the high quality copper ore bodies in the target, demonstrating a positive role of the numerical MTH modeling in facilitating predictive ore discovery.展开更多
This study simulated and predicted the runoff of the Aksu River Basin, a typical river basin supplied by snowmelt in an arid mountain region, with a limited data set and few hydrological and meteorological stations. T...This study simulated and predicted the runoff of the Aksu River Basin, a typical river basin supplied by snowmelt in an arid mountain region, with a limited data set and few hydrological and meteorological stations. Two hydrological models, the snowmelt-runoff model (SRM) and the Danish NedbФr-AfstrФmnings rainfall-runoff model (NAM), were used to simulate daily discharge processes in the Aksu River Basin. This study used the snow-covered area from MODIS remote sensing data as the SRM input. With the help of ArcGIS software, this study successfully derived the digital drainage network and elevation zones of the basin from digital elevation data. The simulation results showed that the SRM based on MODIS data was more accurate than NAM. This demonstrates that the application of remote sensing data to hydrological snowmelt models is a feasible and effective approach to runoff simulation and prediction in arid unguaged basins where snowmelt is a major runoff factor.展开更多
The spatially distributed hydrologic model WetSpa that works on daily, hourly, and minutely timescales is used to predict the flood hydrographs and spatial distribution of the hydrologic characteristics in a river bas...The spatially distributed hydrologic model WetSpa that works on daily, hourly, and minutely timescales is used to predict the flood hydrographs and spatial distribution of the hydrologic characteristics in a river basin by combining elevation, soil and land-use data within Geographical Information System. This model was applied in Ziarat river basin (95.15 km2) located in Golestan Province of Iran. Hourly hydro-meteorological data from 2008 to 2010 consist of precipitation data of two stations, temperature data of one station and evaporation data measured at one station, which were used as input data of the model. Three base maps namely DEM, land-use and soil types were produced in GIS form using 30 × 30 m cell size. Results of the simulations revealed a good agreement between calculated and measured hydrographs at the outlet of the river basin. The model predicted the hourly hydrographs with a good accuracy between 62% - 74% according to the Nash-Sutcliff criteria. To evaluate the model performance during the calibration and validation periods an Aggregated Measure (AM) was introduced that measures different aspects of the simulated hydrograph such as shape, size, and volume. The statistics of Ziarat river basin showed that the results produced by the model were very good in the calibration and validation periods.展开更多
研究格尔木河流域水文循环过程并预测未来流域水资源的变化特征,对地区生态环境保护和下游盐湖矿产资源可持续开发利用具有重要意义。选取格尔木水文站以上区域构建SWAT(Soil and Water Assessment Tool)分布式水文模型。采用大气同化...研究格尔木河流域水文循环过程并预测未来流域水资源的变化特征,对地区生态环境保护和下游盐湖矿产资源可持续开发利用具有重要意义。选取格尔木水文站以上区域构建SWAT(Soil and Water Assessment Tool)分布式水文模型。采用大气同化数据集为气象驱动,联合区域内纳赤台和格尔木水文站的实测月尺度径流数据进行参数的率定和验证。在率定期和验证期内,纳什效率系数、确定性系数和相对偏差系数均达到了良好的标准,表明SWAT模型在格尔木河高寒山区流域水文过程模拟中具有较好的适用性。研究表明流域降水量偏少,地表径流量、壤中流量与降水量的变化趋势具有较好的一致性,降水量年际变化中蒸散发量为主要消耗量,占40.26%。根据未来气候预测模型RegCM4.6,预测路径浓度RCP2.6、RCP4.5和RCP8.53种情景下格尔木河未来40年径流量呈增加趋势。3种情景下的年平均径流量较基准期(2006—2018年)分别增加了7.63%、11.01%、15.96%;随着温室气体排放浓度的增加,径流量呈现出增加趋势,特别是夏秋季增幅较大。短时间内径流量增大可能会引发格尔木市洪涝灾害,破坏盐湖企业生产设施;但若将洪水资源进行调控和利用,不仅防范了洪涝灾害,同时也利于解决盐湖企业日渐增大的用水需求难题。展开更多
Use of a non-zero hydrologic response unit(HRU) threshold is an effective way of reducing unmanageable HRU numbers and simplifying computational cost in the Soil and Water Assessment Tool(SWAT) hydrologic modelling. H...Use of a non-zero hydrologic response unit(HRU) threshold is an effective way of reducing unmanageable HRU numbers and simplifying computational cost in the Soil and Water Assessment Tool(SWAT) hydrologic modelling. However, being less representative of watershed heterogeneity and increasing the level of model output uncertainty are inevitable when minor HRU combinations are disproportionately eliminated. This study examined 20 scenarios by running the model with various HRU threshold settings to understand the mechanism of HRU threshold effects on watershed representation as well as streamflow predictions and identify the appropriate HRU thresholds. Findings show that HRU numbers decrease sharply with increasing HRU thresholds. Among different HRU threshold scenarios, the composition of land-use, soil, and slope all contribute to notable variations which are directly related to the model input parameters and consequently affect the streamflow predictions. Results indicate that saturated hydraulic conductivity, average slope of the HRU, and curve number are the three key factors affecting stream discharge when changing the HRU thresholds. It is also found that HRU thresholds have little effect on monthly model performance, while evaluation statistics for daily discharges are more sensitive than monthly results. For daily streamflow predictions, thresholds of 5%/5%/5%(land-use/soil/slope) are the optimum HRU threshold level for the watershed to allow full consideration of model accuracy and efficiency in the present work. Besides, the results provide strategies for selecting appropriate HRU thresholds based on the modelling goal.展开更多
Seagull Lake is an unusual saline lake,having a marine spring connected to a large continental ecosystem.With climate change the balance between marine,meteoric and groundwater inputs to,and evaporitic and groundwater
文摘Water level prediction of river runoff is an important part of hydrological forecasting.The change of water level not only has the trend and seasonal characteristics,but also contains the noise factors.And the water level prediction ability of a single model is limited.Since the traditional ARIMA(Autoregressive Integrated Moving Average)model is not accurate enough to predict nonlinear time series,and the WNN(Wavelet Neural Network)model requires a large training set,we proposed a new combined neural network prediction model which combines the WNN model with the ARIMA model on the basis of wavelet decomposition.The combined model fit the wavelet transform sequences whose frequency are high with the WNN,and the scale transform sequence which has low frequency is fitted by the ARIMA model,and then the prediction results of the above are reconstructed by wavelet transform.The daily average water level data of the Liuhe hydrological station in the Chu River Basin of Nanjing are used to forecast the average water level of one day ahead.The combined model is compared with other single models with MATLAB,and the experimental results show that the accuracy of the combined model is improved by 7%compared with the traditional wavelet network under the appropriate wavelet decomposition function and the combined model parameters.
文摘Mineralisation is the result of the coupled multi-geodynamic processes in the crust. The coupled mechano-thermo-hydrological (MTH) processes are the basic physical processes that govern the location of the hydrothermal mineralization, which can be simulated in the computer by using of the numerical codes, such as FLAC. The numerical modeling results can be used not only to explain the features of existing ore deposits, but also to predict the favorable mineralization locations. This paper has summarized the basic equations describing coupled MHT processes in the water-saturated porous rocks, the principles of FLAC, and its application to the MHT processes related to copper mineralization in the Fenghuangshan ore field. We used the FLAC to simulate the syn-deformation cooling and fluid flowing evolution after the intrusion was emplaced and solidified. The modeling results suggest a most prospective exploration area where the subsequent exploration supported the prediction and the test bore hole disclosed the high quality copper ore bodies in the target, demonstrating a positive role of the numerical MTH modeling in facilitating predictive ore discovery.
基金supported by the National Basic Research Program of China(Grant No.2006CB400502)the World Bank Cooperative Project(Grant No.THSD-07)the 111 Program of the Ministry of Education and the State Administration of Foreign Expert Affairs,China(Grant No.B08048)
文摘This study simulated and predicted the runoff of the Aksu River Basin, a typical river basin supplied by snowmelt in an arid mountain region, with a limited data set and few hydrological and meteorological stations. Two hydrological models, the snowmelt-runoff model (SRM) and the Danish NedbФr-AfstrФmnings rainfall-runoff model (NAM), were used to simulate daily discharge processes in the Aksu River Basin. This study used the snow-covered area from MODIS remote sensing data as the SRM input. With the help of ArcGIS software, this study successfully derived the digital drainage network and elevation zones of the basin from digital elevation data. The simulation results showed that the SRM based on MODIS data was more accurate than NAM. This demonstrates that the application of remote sensing data to hydrological snowmelt models is a feasible and effective approach to runoff simulation and prediction in arid unguaged basins where snowmelt is a major runoff factor.
文摘The spatially distributed hydrologic model WetSpa that works on daily, hourly, and minutely timescales is used to predict the flood hydrographs and spatial distribution of the hydrologic characteristics in a river basin by combining elevation, soil and land-use data within Geographical Information System. This model was applied in Ziarat river basin (95.15 km2) located in Golestan Province of Iran. Hourly hydro-meteorological data from 2008 to 2010 consist of precipitation data of two stations, temperature data of one station and evaporation data measured at one station, which were used as input data of the model. Three base maps namely DEM, land-use and soil types were produced in GIS form using 30 × 30 m cell size. Results of the simulations revealed a good agreement between calculated and measured hydrographs at the outlet of the river basin. The model predicted the hourly hydrographs with a good accuracy between 62% - 74% according to the Nash-Sutcliff criteria. To evaluate the model performance during the calibration and validation periods an Aggregated Measure (AM) was introduced that measures different aspects of the simulated hydrograph such as shape, size, and volume. The statistics of Ziarat river basin showed that the results produced by the model were very good in the calibration and validation periods.
文摘研究格尔木河流域水文循环过程并预测未来流域水资源的变化特征,对地区生态环境保护和下游盐湖矿产资源可持续开发利用具有重要意义。选取格尔木水文站以上区域构建SWAT(Soil and Water Assessment Tool)分布式水文模型。采用大气同化数据集为气象驱动,联合区域内纳赤台和格尔木水文站的实测月尺度径流数据进行参数的率定和验证。在率定期和验证期内,纳什效率系数、确定性系数和相对偏差系数均达到了良好的标准,表明SWAT模型在格尔木河高寒山区流域水文过程模拟中具有较好的适用性。研究表明流域降水量偏少,地表径流量、壤中流量与降水量的变化趋势具有较好的一致性,降水量年际变化中蒸散发量为主要消耗量,占40.26%。根据未来气候预测模型RegCM4.6,预测路径浓度RCP2.6、RCP4.5和RCP8.53种情景下格尔木河未来40年径流量呈增加趋势。3种情景下的年平均径流量较基准期(2006—2018年)分别增加了7.63%、11.01%、15.96%;随着温室气体排放浓度的增加,径流量呈现出增加趋势,特别是夏秋季增幅较大。短时间内径流量增大可能会引发格尔木市洪涝灾害,破坏盐湖企业生产设施;但若将洪水资源进行调控和利用,不仅防范了洪涝灾害,同时也利于解决盐湖企业日渐增大的用水需求难题。
基金Under the auspices of National Natural Science Foundation of China(No.31901153)Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA23070103)。
文摘Use of a non-zero hydrologic response unit(HRU) threshold is an effective way of reducing unmanageable HRU numbers and simplifying computational cost in the Soil and Water Assessment Tool(SWAT) hydrologic modelling. However, being less representative of watershed heterogeneity and increasing the level of model output uncertainty are inevitable when minor HRU combinations are disproportionately eliminated. This study examined 20 scenarios by running the model with various HRU threshold settings to understand the mechanism of HRU threshold effects on watershed representation as well as streamflow predictions and identify the appropriate HRU thresholds. Findings show that HRU numbers decrease sharply with increasing HRU thresholds. Among different HRU threshold scenarios, the composition of land-use, soil, and slope all contribute to notable variations which are directly related to the model input parameters and consequently affect the streamflow predictions. Results indicate that saturated hydraulic conductivity, average slope of the HRU, and curve number are the three key factors affecting stream discharge when changing the HRU thresholds. It is also found that HRU thresholds have little effect on monthly model performance, while evaluation statistics for daily discharges are more sensitive than monthly results. For daily streamflow predictions, thresholds of 5%/5%/5%(land-use/soil/slope) are the optimum HRU threshold level for the watershed to allow full consideration of model accuracy and efficiency in the present work. Besides, the results provide strategies for selecting appropriate HRU thresholds based on the modelling goal.
基金Financial assistance for the researchers to undertake the initial fieldwork in 2012 was provided by the Friends of Streaky Bay Parks as a Caring for our Country grantThe Royal Society of South Australia provided a research grant to assist with the continuation of the work in 2013
文摘Seagull Lake is an unusual saline lake,having a marine spring connected to a large continental ecosystem.With climate change the balance between marine,meteoric and groundwater inputs to,and evaporitic and groundwater