格尔木河水质现状及生态风险评估

为了解经济迅速发展背景下格尔木河流域水体中痕量元素分布、水环境质量现状和生态风险,对格尔木河9个采样点水样21种痕量元素的分布及相关性进行了分析,以Cu、Zn、Hg、Cd、Cr和Pb为目标重金属,评估了格尔木河水质现状及生态风险。结果表明:重金属Pb浓度在所有水样中均低于检出限,其它痕量元素浓度在0.001(Cd)～6297.013(Sr)μg·L~(-1)范围变化。根据相关性分析,推测格尔木河水体中Li、Sc、Ti、V、Cu、Ge、Rb、Sr、Mo、Cd来源可能相同。采样点水样6种重金属浓度均达到地表水环境质量I类的标准。采用5种方法评价了格尔木河水质现状,研究区水质处于无污染的理想状态。格尔木河重金属引发的潜在生态风险处于低风险水平(生态风险指数变化范围为0.35～0.68)。     

The influence of rainfall and land use patterns on soil erosion in multi-scale watersheds: A case study in the hilly and gully area on the Loess Plateau,China

Soil erosion has become a major global environmental problem and is particularly acute on the Loess Plateau (LP), China. It is therefore highly important to control this process in order to improve ecosystems, protect ecological security, and maintain the harmonious relationship between humans and nature. We compared the effects of rainfall and land use (LU) patterns on soil erosion in different LP watersheds in this study in order to augment and improve soil erosion models. As most research on this theme has so far been focused on individual study areas, limited analyses of rainfall and LU patterns on soil erosion within different- scale watersheds has so far been performed, a discrepancy which might influence the simulation accuracies of soil erosion models. We therefore developed rainfall and LU pattern indices in this study using the soil erosion evaluation index as a reference and applied them to predict the extent of this process in different-scale watersheds, an approach which is likely to play a crucial role in enabling the comprehensive management of this phenomenon as well as the optimized design of LU patterns. The areas considered in this study included the Qingjian, Fenchuan, Yanhe, and Dali river watersheds. Results showed that the rainfall erosivity factor (R) tended to increase in these areas from 2006 to 2012, while the vegetation cover and management factor (C) tended to decrease. Results showed that as watershed area increased, the effect of rainfall pattern on soil erosion gradually decreased while patterns in LU trended in the opposite direction, as the relative proportion of woodland decreased and the different forms of steep slope vegetation cover became more homogenous. As watershed area increased, loose soil and craggy terrain properties led to additional gravitational erosion and enhanced the effects of both soil and topography.     

青海省盐湖钾、镁、锂盐资源开发利用探讨

论述了青海省盐湖资源中钾、镁、锂盐工业的资源状况、生产现状以及开发利用的迫切性 ,并对钾、镁、锂盐资源的综合利用进行了探讨     

大规模地形实时绘制算法

该文提出一种适合大规模地形实时绘制的简单高效的LOD简化算法。该算法使用一种紧凑有效的规则网格表示方法,优化网格节点的数目,减少可视化过程中的计算量,降低额外内存开销。探讨该算法相关的数据组织、视域裁剪、LOD层次选择、裂缝消除、三角形化等关键问题。实验结果表明,该算法实现简单,内存开销较少,CPU耗费小,对图形卡要求低,能够在普通机器上实现大规模地形的实时漫游。     

我国城乡关联度评价指标体系构建及区域比较分析

科学评价城乡关系的发展程度和发展状况是城乡一体化研究中需要解决的关键问题。本文在分析了影响城乡融合诸多因素的基础上 ,运用层次分析法构建了一套用以反映区域城乡关系发展特征及程度的评价指标体系 ;并用此评价指标体系的综合评价值———城乡关联度对我国 31个省 (直辖市 ) 2 0 0 0年城乡关系发展状态进行了静态评价 ,评价结果比较真实地反映了城乡两大开放系统之间的要素流转情况和区域城乡关系发展的实际水平。文中对城乡关联度概念及其评价方法的提出是对城乡关系及其量化评价研究所做的有益尝试。     

淮河流域水文随机方法的径流图化(英文)

Theoretical difficulties for mapping and for estimating river regime characteristics in a large-scale basin remain because of the nature of the variable under study: river flows are related to a specific area, i.e. the drainage basin, and are hierarchically organized in space through the river network with upstream-downstream dependencies. Another limitation is there are not enough gauge stations in developing countries. This presentation aims at de-veloping the hydro-stochastic approach for producing choropleth maps of average annual runoff and computing mean discharge along the main river network for a large-scale basin. The approach applied to mean annual runoff is based on geostatistical interpolation proce-dures coupled with water balance and data uncertainty analyses. It is proved by an applica-tion in the upstream at Bengbu in the Huaihe River Basin, a typical large-scale basin in China. Hydro-stochasitic approach in a first step interpolates to a regular grid net and in a second step the grid values are integrated along rivers. The interpolation scheme includes a con-straint to be able to account for the lateral water balance along the rivers. Grid runoff map with 10 km × 10 km resolution and the discharge map along the river with the 1 km basic length unit are the main results in this study. This kind of statistic approach can be widely used be-cause it avoids the complexity of hydrological models and does not depend on the meteoro-logical data.     

元谋干热河谷近50 a降水量时间序列的DFA分析

干热河谷是一类特殊的退化生态系统区域,降水对河谷景观格局的变化起着十分重要的作用.基于消除趋势波动分析法(DFA)分析了元谋地区近50 a降雨量变化趋势,同时也对1978～2006年进行了滑移分析.结果表明,元谋地区年均降水量序列至少在50 a的时间尺度上具有微弱的Hurst效应,即具有较弱的长期持续性及较强的随机性.区域植被覆盖率的变化能对该区域降雨量的动力学变化趋势做出有效的解释.     

Unraveling the multi-scalar residential segregation and socio-spatial differentiation in China: A comparative study based on Nanjing and Hangzhou

Residential segregation is a dual process of socio-spatial differentiation in residents and spatio-temporal heterogeneity in dwelling.However,most of the existing studies are es-tablished from the single perspective of urban residents based on demographic data,which is difficult to reveal the dynamics and complex spatial reconstruction within and between cities.With the characteristics of both stability and timeliness,the rapidly changing housing market is one of the processes and results of socio-spatial reconfiguration,and it is undoubtedly a better lens to observe residential segregation.This paper adopts methods such as multi-group segregation index,multi-scalar segregation profiles,and decomposition of segregation index,with Nanjing and Hangzhou as case cities,and establishes multi-scalar segregation profiles and comparative models based on three geographical scales of census tract,block and grid,and different residential types.A quantitative study was conducted on the degree and pattern of multi-scalar residential segregation in Nanjing and Hangzhou from 2009 to 2018.The pa-per found that the spatial segregation index is an improvement of the non-spatial segregation index.There are differences between Nanjing and Hangzhou in the evolution process of residential segregation.Nanjing has a higher degree of spatial differentiation as a whole,among which spatial components have a more significant impact.     

三峡库区梁滩河流域水化学与硝酸盐污染

运用水化学和水质分析技术,测定了三峡库区梁滩河流域地表水体和地下水体中的水化学组成和硝酸盐氮含量,揭示了梁滩河流域地表水和地下水水体的水化学组成和硝酸盐污染的空间分布规律、来源及循环过程。结果表明:梁滩河流域地表水的硝酸盐污染表现为沿着地表径流从上游到下游呈现出加重的趋势,这种污染趋势与养殖业、生活和工农业废污水的沿程直接排放有着直接关系;而地下水硝酸盐污染呈现出流域上游和下游较轻、而中游东侧支流区域较重的空间分布特征,这种空间分布特征与地表水体中氨氮和有机氮的含量、地表水与地下水之间的补给排泄关系、厚层土壤包气带的存在以及土地利用状况等因素有着密切的关系。     

New progress of research on water cycle in atmosphere in China

New progresses are introduced briefly about the water cycle study on atmosphere of China made in recent years. The introduction includes eight aspects as follows: 1) precipitation characteristics, 2) stability of climatic system, 3) precipitation sensitive region, 4) regional evaporation and evapotranspiration, 5) water surface evaporation, 6) vegetation transpiration, 7) cloud physics, and 8) vapor source.