A total of 30 surface sediments samples from the estuary wetland of the Tangxi River, Chaohu Lake Basin were obtained and tested. Enrichment factor （EF） and geoaccumulation index （Igeo） as well as multivariate sta...A total of 30 surface sediments samples from the estuary wetland of the Tangxi River, Chaohu Lake Basin were obtained and tested. Enrichment factor （EF） and geoaccumulation index （Igeo） as well as multivariate statistical analysis methods including Factor Analysis （FA） and Hierarchical Cluster Analysis （HCA） were applied for the assessment of heavy metal pollution in surface sediments. The results of EF values show that the pollution of copper （Cu） and cadmium （Cd） occurs in the estuarine sediments, and that zinc （Zn）, lead （Pb） and chrome （Cr） may originate from crustal materials or natural weathering process. The mean EF values of the five heavy metals are in the decreasing order： Cu〉Cd）Zn〉Pb〉Cr. Based on the lgeo of target heavy metals, the surface sediments collected from the study area can be approximately categorized as unpolluted with Zn, Pb and Cr, and moderately polluted with Cu and Cd. The degree of heavy metal pollution decreases in the order of Cu〉Cd〉Zn〉Pb〉Cr. Three groups of pollution factors are presented from FA： Zn-TOC, Cu-Cd and Cr-Pb, which respectively accounte for 27.22%, 25.20% and 21.05% of variance. By means of HCA, a total number of seven groups are distinguished from 30 sampling sites. Results indicate that Cu and Cd are the prior controlled pollutants in the estuarine sediments of the Tangxi River.展开更多
Flood is one kind of unexpected and the most common natural disasters, which is affected by many factors and has complex mechanism. At home and abroad, there is still no mature theory and method used for the long-term...Flood is one kind of unexpected and the most common natural disasters, which is affected by many factors and has complex mechanism. At home and abroad, there is still no mature theory and method used for the long-term forecast of natural precipitation at present. In the present paper the disadvantages of grey GM (1, 1) and Markov chain are ana- lyzed, and Grey-Markov forecast theory about flood is put forward and then the modifying model is developed by making prediction of Chaohu Lake basin. Hydrological law was conducted based on the theoretical forecasts by grey system GM (1, 1) forecast model with improved Markov chain. The above method contained Stat-analysis, embodying scientific approach, precise forecast and its reliable results.展开更多
快速无序的城市化导致了区域生境斑块间生态联系的退化,生态网络对城市因快速发展而中断的生态过程的恢复具有重要作用。以巢湖流域为例,引入了空间分类系统,综合运用形态空间格局分析、景观连通性分析、最小累积阻力模型、重力模型和...快速无序的城市化导致了区域生境斑块间生态联系的退化,生态网络对城市因快速发展而中断的生态过程的恢复具有重要作用。以巢湖流域为例,引入了空间分类系统,综合运用形态空间格局分析、景观连通性分析、最小累积阻力模型、重力模型和电流理论等方法进行生态网络的构建与优化。研究表明:优化后的巢湖流域生态网络由24个生态源地、57条生态廊道和30个生态节点组成,生态源地总面积为3036.58 km 2,生态廊道总长度为2134.30 km,形成了“一湖八核三带联动、三纵多点蓝绿交织”的结构布局。优化后的巢湖流域生态网络的网络闭合度、点线率、网络连接度分别提升了13.55%、31.62%、9.36%。展开更多
基金Under the auspices of the Key Technology R&D Program of Anhui Province,China (No. 07010302165)
文摘A total of 30 surface sediments samples from the estuary wetland of the Tangxi River, Chaohu Lake Basin were obtained and tested. Enrichment factor （EF） and geoaccumulation index （Igeo） as well as multivariate statistical analysis methods including Factor Analysis （FA） and Hierarchical Cluster Analysis （HCA） were applied for the assessment of heavy metal pollution in surface sediments. The results of EF values show that the pollution of copper （Cu） and cadmium （Cd） occurs in the estuarine sediments, and that zinc （Zn）, lead （Pb） and chrome （Cr） may originate from crustal materials or natural weathering process. The mean EF values of the five heavy metals are in the decreasing order： Cu〉Cd）Zn〉Pb〉Cr. Based on the lgeo of target heavy metals, the surface sediments collected from the study area can be approximately categorized as unpolluted with Zn, Pb and Cr, and moderately polluted with Cu and Cd. The degree of heavy metal pollution decreases in the order of Cu〉Cd〉Zn〉Pb〉Cr. Three groups of pollution factors are presented from FA： Zn-TOC, Cu-Cd and Cr-Pb, which respectively accounte for 27.22%, 25.20% and 21.05% of variance. By means of HCA, a total number of seven groups are distinguished from 30 sampling sites. Results indicate that Cu and Cd are the prior controlled pollutants in the estuarine sediments of the Tangxi River.
基金Under the auspices of the National Natural Science Foundation of China (No. 40571162)the Natural Science Foun-dation of Anhui Province (No. 050450401)
文摘Flood is one kind of unexpected and the most common natural disasters, which is affected by many factors and has complex mechanism. At home and abroad, there is still no mature theory and method used for the long-term forecast of natural precipitation at present. In the present paper the disadvantages of grey GM (1, 1) and Markov chain are ana- lyzed, and Grey-Markov forecast theory about flood is put forward and then the modifying model is developed by making prediction of Chaohu Lake basin. Hydrological law was conducted based on the theoretical forecasts by grey system GM (1, 1) forecast model with improved Markov chain. The above method contained Stat-analysis, embodying scientific approach, precise forecast and its reliable results.
文摘快速无序的城市化导致了区域生境斑块间生态联系的退化,生态网络对城市因快速发展而中断的生态过程的恢复具有重要作用。以巢湖流域为例,引入了空间分类系统,综合运用形态空间格局分析、景观连通性分析、最小累积阻力模型、重力模型和电流理论等方法进行生态网络的构建与优化。研究表明:优化后的巢湖流域生态网络由24个生态源地、57条生态廊道和30个生态节点组成,生态源地总面积为3036.58 km 2,生态廊道总长度为2134.30 km,形成了“一湖八核三带联动、三纵多点蓝绿交织”的结构布局。优化后的巢湖流域生态网络的网络闭合度、点线率、网络连接度分别提升了13.55%、31.62%、9.36%。
