Individual participation of pollutants in the pollution load should be estimated even if roughly for the appropriate environmental management of a river basin.It is difficult to identify the sources and to quantify th...Individual participation of pollutants in the pollution load should be estimated even if roughly for the appropriate environmental management of a river basin.It is difficult to identify the sources and to quantify the load, especially in modeling nonpoint source.In this study a revised model was established by integrating point and nonpoint sources into one-dimensional Streeter-Phelps(S-P) model on the basis of real-time hydrologic data and surface water quality monitoring data in the Jilin Reach of the Songhua River Basin.Chemical oxygen demand(COD) and ammonia nitrogen(NH 3-N) loads were estimated.Results showed that COD loads of point source and nonpoint source were 134 958 t/yr and 86 209 t/yr, accounting for 61.02% and 38.98% of total loads, respectively.NH 3-N loads of point source and nonpoint source were 16 739 t/yr and 14 272 t/yr, accounting for 53.98% and 46.02%, respectively.Point source pollution was stronger than nonpoint source pollution in the study area at present.The water quality of upstream was better than that of downstream of the rivers and cities.It is indispensable to treat industrial wastewater and municipal sewage out of point sources, to adopt the best management practices to control diffuse pollutants from agricultural land and urban surface runoff in improving water quality of the Songhua River Basin.The revised S-P model can be successfully used to identify pollution source and quantify point source and nonpoint source loads by calibrating and validating.展开更多
The source and sink landscape patterns refer to landscape types or units that can either promote positive evolvement of non-point source(NPS) pollution process, or can prevent/defer the ecological process, respectivel...The source and sink landscape patterns refer to landscape types or units that can either promote positive evolvement of non-point source(NPS) pollution process, or can prevent/defer the ecological process, respectively. Therefore, the role of a catchment landscape pattern in nutrient losses can be identified based on the spatial arrangement of source and sink landscapes. To reveal the relations between landscape spatial characteristics and NPS pollution in small catchment, a case study was carried out in a Wangjiagou small catchment of the Three Gorges Reservoir Region(TGRR), China. Google earth imagery for 2015 were processed and used to differentiate source and sink landscape types, and six subcatchments were selected as sample regions for monitoring nitrogen and phosphorus nutrients.Relative elevation, slope gradient and relative flow length was used to construct the Lorenz curves of different source and sink landscape types in the catchment, in order to assess the source and sink landscape spatial characteristics. By calculating the location-weighted landscape indices of each subcatchment and total catchment, the landscape spatial load characteristics affecting the NPS pollution was identified, with a further Pearson correlation analysis for location-weighted landscape indices and nitrogen-phosphorus monitoring indicators. The analysis of Lorenz curve has revealed that the obtained distribution trend of Lorenz curve and curve area quantified well the spatial characteristics of source and sink landscape pattern related to the relative elevation, slope gradient and relative flow length in small catchment. Results of Pearson correction analysis indicated that location-weighted landscape index(LWLI) combining of terrain and landscape type factor did better in reflecting the status of nitrogen and phosphorus loss than the indices related to relative elevation, slope gradient and relative flow length.展开更多
In a multi-source acoustic field, the actual measured pressure is a scalar sum of pressures from all the sources. The pressure belonging to every source cannot be separated out with the existing techniques. Consequent...In a multi-source acoustic field, the actual measured pressure is a scalar sum of pressures from all the sources. The pressure belonging to every source cannot be separated out with the existing techniques. Consequently, routine formulas cannot be used to reconstruct the acoustic source and predict the acoustic field directly. In this paper, a novel theoretical model of reconstruction and prediction of multi-source acoustic field in the distributed source boundary point method (DSBPM) based nearfield acoustic holography (NAH) is established. Three different methods, namely combination method with single surface measurement, combination method with multi-surface measurement and elimination method with multi-surface measurement, are proposed to realize the holographic reconstruction of sources. With these methods, the problem of reconstruction and prediction of acoustic field existing multiple coherent sources synchronously is solved effectively. Using the particular solutions constructed by the DSBPM to establish the vibro-acoustic transfer matrix, the calculation time, calculation precision and calculation stability are improved. These methods are valuable in localizing acoustic source and predicting acoustic field in engineering field.展开更多
Advancing the understanding of the spatial aspects of air pollution in the city regional environment is an area where improved methods can be of great benefit to exposure assessment and policy support. We created land...Advancing the understanding of the spatial aspects of air pollution in the city regional environment is an area where improved methods can be of great benefit to exposure assessment and policy support. We created land use regression （LUR） models for SO2, NO2 and PMI0 for Tianjin, China. Traffic volumes, road networks, land use data, population density, meteorological conditions, physical conditions and satellite-derived greenness, brightness and wetness were used for predicting SOa, NO2 and PMt0 concentrations. We incorporated data on industrial point sources to improve LUR model performance. In order to consider the impact of different sources, we calculated the PSIndex, LSIndex and area of different land use types （agricultural land, industrial land, commercial land, residential land, green space and water area） within different buffer radii （1 to 20 kin）. This method makes up for the lack of consideration of source impact based on the LUR model. Remote sensing-derived variables were significantly correlated with gaseous pollutant concentrations such as SO2 and NO2. R2 values of the multiple linear regression equations for SO2, NO2 and PM10 were 0.78, 0.89 and 0.84, respectively, and the RMSE values were 0.32, 0.18 and 0.21, respectively. Model predictions at validation monitoring sites went well with predictions generally within 15% of measured values. Compared to the relationship between dependent variables and simple variables （such as traffic variables or meteorological condition variables）, the relationship between dependent variables and integrated variables was more consistent with a linear relationship. Such integration has a discernable influence on both the overall model prediction and health effects assessment on the spatial distribution of air pollution in the city region.展开更多
The growth of society and population has led to a range of water pollution issues.Among these,non-point source pollution assessment and treatment pose a particular challenge due to its formation mechanism.This has bec...The growth of society and population has led to a range of water pollution issues.Among these,non-point source pollution assessment and treatment pose a particular challenge due to its formation mechanism.This has become a focal point and challenge in water pollution treatment research.The study area for this research was the Huanghou basin in Guizhou Province,southwest China.The land use type of the basin was analyzed using remote sensing technology,and water quality data was collected by distributing points throughout the basin,based on source-sink landscape theory.The distribution map of the basin’s source-sink landscape and the results of water quality data accurately and efficiently identified the areas with high risk of non-point source pollution in the western and southwestern residential and agricultural areas of the upper basin.Hence,a strategy of“increasing sinks and decreasing sources”was proposed.The strategy was implemented at both macro and micro levels to address non-point source pollution in the basin using ecological remediation techniques.The work to control karst rocky desertification should continue at a macro level.The rocky desertification area in the basin should gradually transform into grassland and forested land,while increasing the overall area of the sink landscape.Ecological restoration techniques,such as slope planting,riparian zone vegetation restoration,increasing plant abundance,and restoring aquatic plants,can effectively control non-point source pollution at the micro level.Compared to traditional control methods,this remediation strategy focuses on source and process control.It is more effective and does not require large-scale water pollution control projects,which can save a lot of environmental control funds and management costs.Therefore,it has greater research significance and application value.展开更多
The Yellow River Basin (YRB) plays a very important role in China’s economic and social development and ecological security.In particular,the ecosystem of the YRB is sensitive to climate change.However,the change of ...The Yellow River Basin (YRB) plays a very important role in China’s economic and social development and ecological security.In particular,the ecosystem of the YRB is sensitive to climate change.However,the change of nutrient fluxes in this region during the past years and its main driving forces remain unclear.In this study,a hydrologic model R System for Spatially Referenced Regressions on Watershed Attributes (RSPARROW) was employed to simulate the spatio-temporal variations in the fluxes of total nitrogen (TN) and total phosphorus (TP) during the period of 2006-2017.The results suggested that the TN and TP loads increased by 138%and 38%during 2006-2014,respectively,and decreased by 66%and 71%from 2015 to 2017,respectively.During the period of 2006-2017,the annual mean fluxes of TN and TP in the YRB were in the range of 3.9 to 591.6 kg/km^(2)/year and 1.7 to 12.0 kg/km^(2)/year,respectively.TN flux was low in the upstream area of the Yellow River,and presented a high level in the middle and lower reaches.However,the flux of TP in Gansu and Ningxia section was slightly higher than that in the lower reaches of the Yellow River.Precipitation and point source are the key drivers for the inter-annual changes of TN loads in most regions of the YRB.While the inter-annual variations of TP loads in the whole basin are mainly driven by the point source.This study demonstrates the important impacts of climate change on nutrient loads in the YRB.Moreover,management measures should be taken to reduce pollution sources and thus provide solid basis for control of nitrogen and phosphorus in the YRB.展开更多
基金Under the auspices of Major State Basic Research Development Program of China (973 Program) (No. 2004CB418502,No. 2007CB407205)the Knowledge Innovation Programs of Chinese Academy of Sciences (No. KSCX1-YW-09-13)
文摘Individual participation of pollutants in the pollution load should be estimated even if roughly for the appropriate environmental management of a river basin.It is difficult to identify the sources and to quantify the load, especially in modeling nonpoint source.In this study a revised model was established by integrating point and nonpoint sources into one-dimensional Streeter-Phelps(S-P) model on the basis of real-time hydrologic data and surface water quality monitoring data in the Jilin Reach of the Songhua River Basin.Chemical oxygen demand(COD) and ammonia nitrogen(NH 3-N) loads were estimated.Results showed that COD loads of point source and nonpoint source were 134 958 t/yr and 86 209 t/yr, accounting for 61.02% and 38.98% of total loads, respectively.NH 3-N loads of point source and nonpoint source were 16 739 t/yr and 14 272 t/yr, accounting for 53.98% and 46.02%, respectively.Point source pollution was stronger than nonpoint source pollution in the study area at present.The water quality of upstream was better than that of downstream of the rivers and cities.It is indispensable to treat industrial wastewater and municipal sewage out of point sources, to adopt the best management practices to control diffuse pollutants from agricultural land and urban surface runoff in improving water quality of the Songhua River Basin.The revised S-P model can be successfully used to identify pollution source and quantify point source and nonpoint source loads by calibrating and validating.
基金funded by the National Natural Science Foundation of China (Grant No.41671291)
文摘The source and sink landscape patterns refer to landscape types or units that can either promote positive evolvement of non-point source(NPS) pollution process, or can prevent/defer the ecological process, respectively. Therefore, the role of a catchment landscape pattern in nutrient losses can be identified based on the spatial arrangement of source and sink landscapes. To reveal the relations between landscape spatial characteristics and NPS pollution in small catchment, a case study was carried out in a Wangjiagou small catchment of the Three Gorges Reservoir Region(TGRR), China. Google earth imagery for 2015 were processed and used to differentiate source and sink landscape types, and six subcatchments were selected as sample regions for monitoring nitrogen and phosphorus nutrients.Relative elevation, slope gradient and relative flow length was used to construct the Lorenz curves of different source and sink landscape types in the catchment, in order to assess the source and sink landscape spatial characteristics. By calculating the location-weighted landscape indices of each subcatchment and total catchment, the landscape spatial load characteristics affecting the NPS pollution was identified, with a further Pearson correlation analysis for location-weighted landscape indices and nitrogen-phosphorus monitoring indicators. The analysis of Lorenz curve has revealed that the obtained distribution trend of Lorenz curve and curve area quantified well the spatial characteristics of source and sink landscape pattern related to the relative elevation, slope gradient and relative flow length in small catchment. Results of Pearson correction analysis indicated that location-weighted landscape index(LWLI) combining of terrain and landscape type factor did better in reflecting the status of nitrogen and phosphorus loss than the indices related to relative elevation, slope gradient and relative flow length.
基金the National Natural Science Foundation of China (Grant No. 50275044) the Research Fund for the Doctoral Program of Higher Education (Grant No. 20020359005) the Key Project of Chinese Ministry of Education (Grant No. 02126).
文摘In a multi-source acoustic field, the actual measured pressure is a scalar sum of pressures from all the sources. The pressure belonging to every source cannot be separated out with the existing techniques. Consequently, routine formulas cannot be used to reconstruct the acoustic source and predict the acoustic field directly. In this paper, a novel theoretical model of reconstruction and prediction of multi-source acoustic field in the distributed source boundary point method (DSBPM) based nearfield acoustic holography (NAH) is established. Three different methods, namely combination method with single surface measurement, combination method with multi-surface measurement and elimination method with multi-surface measurement, are proposed to realize the holographic reconstruction of sources. With these methods, the problem of reconstruction and prediction of acoustic field existing multiple coherent sources synchronously is solved effectively. Using the particular solutions constructed by the DSBPM to establish the vibro-acoustic transfer matrix, the calculation time, calculation precision and calculation stability are improved. These methods are valuable in localizing acoustic source and predicting acoustic field in engineering field.
基金supported by the Special Environmental Research Funds for Public Welfare (No. 200909005)the National Natural Science Foundation of China (No.20677030)the Doctor Funds of Tianjin Normal University (No. 52XB1110)
文摘Advancing the understanding of the spatial aspects of air pollution in the city regional environment is an area where improved methods can be of great benefit to exposure assessment and policy support. We created land use regression （LUR） models for SO2, NO2 and PMI0 for Tianjin, China. Traffic volumes, road networks, land use data, population density, meteorological conditions, physical conditions and satellite-derived greenness, brightness and wetness were used for predicting SOa, NO2 and PMt0 concentrations. We incorporated data on industrial point sources to improve LUR model performance. In order to consider the impact of different sources, we calculated the PSIndex, LSIndex and area of different land use types （agricultural land, industrial land, commercial land, residential land, green space and water area） within different buffer radii （1 to 20 kin）. This method makes up for the lack of consideration of source impact based on the LUR model. Remote sensing-derived variables were significantly correlated with gaseous pollutant concentrations such as SO2 and NO2. R2 values of the multiple linear regression equations for SO2, NO2 and PM10 were 0.78, 0.89 and 0.84, respectively, and the RMSE values were 0.32, 0.18 and 0.21, respectively. Model predictions at validation monitoring sites went well with predictions generally within 15% of measured values. Compared to the relationship between dependent variables and simple variables （such as traffic variables or meteorological condition variables）, the relationship between dependent variables and integrated variables was more consistent with a linear relationship. Such integration has a discernable influence on both the overall model prediction and health effects assessment on the spatial distribution of air pollution in the city region.
文摘The growth of society and population has led to a range of water pollution issues.Among these,non-point source pollution assessment and treatment pose a particular challenge due to its formation mechanism.This has become a focal point and challenge in water pollution treatment research.The study area for this research was the Huanghou basin in Guizhou Province,southwest China.The land use type of the basin was analyzed using remote sensing technology,and water quality data was collected by distributing points throughout the basin,based on source-sink landscape theory.The distribution map of the basin’s source-sink landscape and the results of water quality data accurately and efficiently identified the areas with high risk of non-point source pollution in the western and southwestern residential and agricultural areas of the upper basin.Hence,a strategy of“increasing sinks and decreasing sources”was proposed.The strategy was implemented at both macro and micro levels to address non-point source pollution in the basin using ecological remediation techniques.The work to control karst rocky desertification should continue at a macro level.The rocky desertification area in the basin should gradually transform into grassland and forested land,while increasing the overall area of the sink landscape.Ecological restoration techniques,such as slope planting,riparian zone vegetation restoration,increasing plant abundance,and restoring aquatic plants,can effectively control non-point source pollution at the micro level.Compared to traditional control methods,this remediation strategy focuses on source and process control.It is more effective and does not require large-scale water pollution control projects,which can save a lot of environmental control funds and management costs.Therefore,it has greater research significance and application value.
基金supported by the National Key Research and Development Program of China (No.2017YFA060500)the National Natural Science Foundation of China (Nos.51922010,41521003)。
文摘The Yellow River Basin (YRB) plays a very important role in China’s economic and social development and ecological security.In particular,the ecosystem of the YRB is sensitive to climate change.However,the change of nutrient fluxes in this region during the past years and its main driving forces remain unclear.In this study,a hydrologic model R System for Spatially Referenced Regressions on Watershed Attributes (RSPARROW) was employed to simulate the spatio-temporal variations in the fluxes of total nitrogen (TN) and total phosphorus (TP) during the period of 2006-2017.The results suggested that the TN and TP loads increased by 138%and 38%during 2006-2014,respectively,and decreased by 66%and 71%from 2015 to 2017,respectively.During the period of 2006-2017,the annual mean fluxes of TN and TP in the YRB were in the range of 3.9 to 591.6 kg/km^(2)/year and 1.7 to 12.0 kg/km^(2)/year,respectively.TN flux was low in the upstream area of the Yellow River,and presented a high level in the middle and lower reaches.However,the flux of TP in Gansu and Ningxia section was slightly higher than that in the lower reaches of the Yellow River.Precipitation and point source are the key drivers for the inter-annual changes of TN loads in most regions of the YRB.While the inter-annual variations of TP loads in the whole basin are mainly driven by the point source.This study demonstrates the important impacts of climate change on nutrient loads in the YRB.Moreover,management measures should be taken to reduce pollution sources and thus provide solid basis for control of nitrogen and phosphorus in the YRB.
