The developmental characteristics of groundwater flow system are not only controlled by formation lithology and groundwater recharge conditions,but also influenced by the physical properties of fluids.Numerical simula...The developmental characteristics of groundwater flow system are not only controlled by formation lithology and groundwater recharge conditions,but also influenced by the physical properties of fluids.Numerical simulation is an effective way to study groundwater flow system.In this paper,the ideal model is generalized according to the fundamental characteristics of groundwater system in inland basins of Western China.The simulation method of variable density flow on the development of groundwater system in inland basins is established by using EOS9 module in TOUGHREACT numerical simulation software.In accordance with the groundwater streamline,the groundwater flow system is divided into three levels,which are regional groundwater flow system,intermediate groundwater flow system and local groundwater flow system.Based on the calculation of the renewal rate of groundwater,the analysis shows that the increase of fluid density in the central part of the basin will restrain the development of regional groundwater flow system,resulting in a decrease of the circulation rate from 32.28% to 17.62% and a certain enhancement to the local groundwater flow system,which increased from 37.29% to 51.94%.展开更多
Hydrological circulation,as the most basic material cycle and active natural phenomenon on earth,exerts a significant in fluence on climate change.The mid-Holocene is an important period to better understand modern en...Hydrological circulation,as the most basic material cycle and active natural phenomenon on earth,exerts a significant in fluence on climate change.The mid-Holocene is an important period to better understand modern environmental change;however,little research has focused on its quantitative simulation of paleo-hydrological process.In this research,we first collected chronological evidence and sediment records from six Holocene sedimentary sections in the Shiyang River Ba sin to reconstruct the mid-Holocene environment and terminal paleo-lake area.Secondly,we comprehensively analyzed modern pollen combinations and their propagation characteristics in surface soil,air,river and lacustrine sediments in the Shiyang River Basin,and combined the pollen records,as well as quantitatively reconstructed the millennial-scale vegeta tion zones.Finally,based on the land-cover adjustment results during the mid-Holocene,we successfully used the Soil and Water Assessment Tool(SWAT)model,a modern distributed hydrological watershed model,to simulate mid-Holocene runoff in the basin.Results show that the reconstructed climate in the basin was warmer and moister than that in recent times.Vegetation types in the mid-Holocene mainly consisted of sub-alpine shrub distributed between 2,550 m and 2,750 m,forest at an elevation of 2,550 2,750 m,steppe at an elevation of 1,550 2,150 m and desert steppe below 1,550 m.The up stream,midstream,downstream and average annual runoff of the mid-Holocene in the basin were 16.76×10^8 m^3,22.86×10^8 m^3,9.00×10^8 m^3 and 16.20×10^8 m^3 respectively,compared to 15.61×10^8 m^3 of modern annual runoff.Also,the area of terminal paleo-lake in the mid-Holocene was 628 km^2.Thus,this study provides a new quantitative method for paleo-hy drological simulation.展开更多
基金jointly funded by the National Natural Science Foundation of China (41702282, 41602268)China Geological Survey Project (DD20160311, DD20160238)the Basic Research Service Fee of the Chinese Academy of Geological Sciences (YYWF201626)
文摘The developmental characteristics of groundwater flow system are not only controlled by formation lithology and groundwater recharge conditions,but also influenced by the physical properties of fluids.Numerical simulation is an effective way to study groundwater flow system.In this paper,the ideal model is generalized according to the fundamental characteristics of groundwater system in inland basins of Western China.The simulation method of variable density flow on the development of groundwater system in inland basins is established by using EOS9 module in TOUGHREACT numerical simulation software.In accordance with the groundwater streamline,the groundwater flow system is divided into three levels,which are regional groundwater flow system,intermediate groundwater flow system and local groundwater flow system.Based on the calculation of the renewal rate of groundwater,the analysis shows that the increase of fluid density in the central part of the basin will restrain the development of regional groundwater flow system,resulting in a decrease of the circulation rate from 32.28% to 17.62% and a certain enhancement to the local groundwater flow system,which increased from 37.29% to 51.94%.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41822708 and 41571178)the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDA20100102)+1 种基金the Fundamental Research Funds for the Central Universities (Grant No. lzujbky-2018k15)the Second Tibetan Plateau Scientific Expedition (STEP) program (Grant No. XDA20060700)
文摘Hydrological circulation,as the most basic material cycle and active natural phenomenon on earth,exerts a significant in fluence on climate change.The mid-Holocene is an important period to better understand modern environmental change;however,little research has focused on its quantitative simulation of paleo-hydrological process.In this research,we first collected chronological evidence and sediment records from six Holocene sedimentary sections in the Shiyang River Ba sin to reconstruct the mid-Holocene environment and terminal paleo-lake area.Secondly,we comprehensively analyzed modern pollen combinations and their propagation characteristics in surface soil,air,river and lacustrine sediments in the Shiyang River Basin,and combined the pollen records,as well as quantitatively reconstructed the millennial-scale vegeta tion zones.Finally,based on the land-cover adjustment results during the mid-Holocene,we successfully used the Soil and Water Assessment Tool(SWAT)model,a modern distributed hydrological watershed model,to simulate mid-Holocene runoff in the basin.Results show that the reconstructed climate in the basin was warmer and moister than that in recent times.Vegetation types in the mid-Holocene mainly consisted of sub-alpine shrub distributed between 2,550 m and 2,750 m,forest at an elevation of 2,550 2,750 m,steppe at an elevation of 1,550 2,150 m and desert steppe below 1,550 m.The up stream,midstream,downstream and average annual runoff of the mid-Holocene in the basin were 16.76×10^8 m^3,22.86×10^8 m^3,9.00×10^8 m^3 and 16.20×10^8 m^3 respectively,compared to 15.61×10^8 m^3 of modern annual runoff.Also,the area of terminal paleo-lake in the mid-Holocene was 628 km^2.Thus,this study provides a new quantitative method for paleo-hy drological simulation.
