Surface water bodies are progressively subjected to stress as a result of anthropogenic activities. This study assessed and examined the impact of human activities on spatial variation in the water quality of 19 river...Surface water bodies are progressively subjected to stress as a result of anthropogenic activities. This study assessed and examined the impact of human activities on spatial variation in the water quality of 19 rivers in the Taihu watershed. Concentrations of physicochemical parameters of surface water quality were determined at the mouth of each river during the period of 2000-2004. Multivariate statistical techniques were applied to identify characteristics of the water quality in the studied rivers. The results showed that rivers strongly influenced by household wastewater have the highest concentrations of nutrients （TN and TP）. Moreover, rivers in the vicinity of a metropolis presented low dissolved oxygen （DO） levels. However, organic-chemical pollution （petroleum and volatile phenolics） was identified with high localization. Two rivers influenced by sewage from industry and ships were distinguished from other rivers with high values of petroleum. The Taige channel, a river located in Changzhou City that is strongly influenced by wastewater from industry, was characterized with an extraordinarily high value of volatile phenolics. Rivers passing through countries, especially through hilly countries were characterized with high DO contents and low nutrient and organic-chemical pollution, suggesting that agriculture puts less pressure on water quality in adjacent rivers. Therefore, more effort should be made in controlling point pollution to restore water quality in rivers adjacent to cities.展开更多
This paper outlines a methodology to estimate monthly precipitation surfaces at 1-kin resolution for the Upper Shiyang River watershed （USRW） in northwest China. Generation of precipitation maps is based on the appl...This paper outlines a methodology to estimate monthly precipitation surfaces at 1-kin resolution for the Upper Shiyang River watershed （USRW） in northwest China. Generation of precipitation maps is based on the application of a four-variable genetic algorithm （GA） trained on 10 years of weather and ancillary data, i.e., surface air temperature, relative humidity, Digital Elevation Model-derived estimates of elevation, and time of year collected at 29 weather stations in west-central Gansu and northern Qinghai province. An observed-to-GA predicted data comparison of 10 years of precipitation collected at the 29 weather stations showed that about 84% of the variability in observed values could be explained by the trained GA, including variability in two independent datasets. Point-comparisons of observed and modeled precipitation along an elevation-rainfall gradient demonstrated near-similar spatiotemporal patterns. A precipitation surface for USRW for July, 2005, was developed with the trained GA and input surfaces of surface air temperature and relative humidity generated from Moderate Resolution Imaging Spectroradiometer sensor （MODIS） products of land surface temperature. Spatial tendencies in predicted maximum and minimum values of surface air temperature, relative humidity, and precipitation within a 2-kin radius circle around selected weather stations were in close agreement with the values measured at the weather stations.展开更多
The determination of the processes responsible for the mineralization of ground-water requires a large number of samples and physicochemical data, the treatment of which proves to be tedious. Many statistical methods ...The determination of the processes responsible for the mineralization of ground-water requires a large number of samples and physicochemical data, the treatment of which proves to be tedious. Many statistical methods are developed to facilitate the treatment of a certain volume of data. In this study, multivariate statistical analysis including principal components analysis (PCA) and hierarchical cluster analysis (HCA) have been applied on the groundwater physicochemical data of the upper Kambo watershed. The aim is to simplify the data in order to evaluate the relationships between the parameters and also to detect the factors that influence the water chemistry. For the PCA, three factors were retained representing 70% of the total inertia. Factor 1 shows the heterogeneity of sources of acquisition of the mineralization by the positive correlation with all the variables. Factor 2 indicates the dissolution of carbonates and anthropogenic input. Factor 3 highlights the silicate, anthropogenic and atmospheric or marine origin. The HCA enables to differentiate 4 groups of water according to the degree of mineralization. Groups 1 and 2 represent the most mineralized waters, dominated by calcium. The poor mineralized waters are groups 3 and 4 with the rather close contents in calcium and sodium.展开更多
基金Project supported by the International Project between The Netherlands Royal Academy of Arts and Sciences and Chinese Academy of Sciences (No. 04CDP014) the National Natural Science Foundation of China (No. 40471130).
文摘Surface water bodies are progressively subjected to stress as a result of anthropogenic activities. This study assessed and examined the impact of human activities on spatial variation in the water quality of 19 rivers in the Taihu watershed. Concentrations of physicochemical parameters of surface water quality were determined at the mouth of each river during the period of 2000-2004. Multivariate statistical techniques were applied to identify characteristics of the water quality in the studied rivers. The results showed that rivers strongly influenced by household wastewater have the highest concentrations of nutrients （TN and TP）. Moreover, rivers in the vicinity of a metropolis presented low dissolved oxygen （DO） levels. However, organic-chemical pollution （petroleum and volatile phenolics） was identified with high localization. Two rivers influenced by sewage from industry and ships were distinguished from other rivers with high values of petroleum. The Taige channel, a river located in Changzhou City that is strongly influenced by wastewater from industry, was characterized with an extraordinarily high value of volatile phenolics. Rivers passing through countries, especially through hilly countries were characterized with high DO contents and low nutrient and organic-chemical pollution, suggesting that agriculture puts less pressure on water quality in adjacent rivers. Therefore, more effort should be made in controlling point pollution to restore water quality in rivers adjacent to cities.
基金funded by the Chinese Meteorological Administration (CMA),the Gansu Provincial Meteorological Bureau (GMB),under the direction of the Lanzhou Regional Climate Centre(Natural Science Foundation of China under Grant No.40830957)the Faculty of Forestry and Environmental Management,University of New Brunswick
文摘This paper outlines a methodology to estimate monthly precipitation surfaces at 1-kin resolution for the Upper Shiyang River watershed （USRW） in northwest China. Generation of precipitation maps is based on the application of a four-variable genetic algorithm （GA） trained on 10 years of weather and ancillary data, i.e., surface air temperature, relative humidity, Digital Elevation Model-derived estimates of elevation, and time of year collected at 29 weather stations in west-central Gansu and northern Qinghai province. An observed-to-GA predicted data comparison of 10 years of precipitation collected at the 29 weather stations showed that about 84% of the variability in observed values could be explained by the trained GA, including variability in two independent datasets. Point-comparisons of observed and modeled precipitation along an elevation-rainfall gradient demonstrated near-similar spatiotemporal patterns. A precipitation surface for USRW for July, 2005, was developed with the trained GA and input surfaces of surface air temperature and relative humidity generated from Moderate Resolution Imaging Spectroradiometer sensor （MODIS） products of land surface temperature. Spatial tendencies in predicted maximum and minimum values of surface air temperature, relative humidity, and precipitation within a 2-kin radius circle around selected weather stations were in close agreement with the values measured at the weather stations.
文摘The determination of the processes responsible for the mineralization of ground-water requires a large number of samples and physicochemical data, the treatment of which proves to be tedious. Many statistical methods are developed to facilitate the treatment of a certain volume of data. In this study, multivariate statistical analysis including principal components analysis (PCA) and hierarchical cluster analysis (HCA) have been applied on the groundwater physicochemical data of the upper Kambo watershed. The aim is to simplify the data in order to evaluate the relationships between the parameters and also to detect the factors that influence the water chemistry. For the PCA, three factors were retained representing 70% of the total inertia. Factor 1 shows the heterogeneity of sources of acquisition of the mineralization by the positive correlation with all the variables. Factor 2 indicates the dissolution of carbonates and anthropogenic input. Factor 3 highlights the silicate, anthropogenic and atmospheric or marine origin. The HCA enables to differentiate 4 groups of water according to the degree of mineralization. Groups 1 and 2 represent the most mineralized waters, dominated by calcium. The poor mineralized waters are groups 3 and 4 with the rather close contents in calcium and sodium.
