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61.
区域场次特大旱灾划分标准与界定——以明清以来的山西省为例 总被引:4,自引:2,他引:2
基于方志、清官档案、民国报刊以及当代的水利、农业和气象资料,以明清以来的山西省为研究对象,探讨了省区性旱灾等级划分方法,即以县级政区为基本分析单元,采用自下而上的等级划分方法。在此基础上,提出了场次特大旱灾的概念,探讨了场次特大旱灾的划分标准,同时对明清以来山西省的场次特大旱灾时限进行了界定。研究发现,明清至2000年,山西省共发生过6场场次特大旱灾。且平均每3a就有2a发生旱灾。其中特大旱灾年12a,大旱灾年50a,中等旱灾年114a,一般旱灾年214a. 相似文献
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63.
M. Gómez‐Delgado S. Tarantola 《International journal of geographical information science》2013,27(4):449-466
A novel application of Sensitivity Analysis is presented. Useful applications of Global SA (GSA) already exist in the field of numerical modelling. In this paper, we explore the joint use of GSA, Geographical Information Systems (GIS) and Multi‐Criteria Evaluation. In this preliminary case study, 11 factors have been used to find the best place to locate a hazardous waste landfill. Two variance‐based methods (Sobol' and E‐FAST) are used to compute sensitivity indices in order to identify the factors that determine the variance of the model output. The results show that only three factors jointly account for 97% of the output variance. This information is employed to make a simplification of the original model, retaining only these three influential factors. In addition, if the SA is carried out in a pilot area where the spatial properties are similar to those of the whole region, we can infer the results to the whole area. This procedure achieves the goal of the study with an optimized allocation of resources for GIS data acquisition. 相似文献
64.
Giancarlo Biotto Lucia Gobbo Elisa Furlan Sonia Valenti Roberto Rosselli 《International journal of geographical information science》2013,27(10):1233-1244
This work deals with the identification of potentially contaminated areas using remote sensing, geographic information systems (GIS) and multi‐criteria spatial analysis. The identification of unknown illegal landfills is a crucial environmental problem in all developed and developing countries, where a large number of illegal waste deposits exist as a result of fast, and relatively unregulated, industrial growth over the past century. The criteria used to perform the spatial analysis are here selected by considering the characteristics which are ‘desirable’ for an illegal waste disposal site, chiefly related to the existence of roads for easy access and to a low population density which facilitates unnoticed dumping of illegal waste materials. A large dataset describing known legal and illegal landfills and the context of their location (population, road network, etc.) was used to perform a spatial statistical analysis to select factors and criteria allowing for the identification of the known waste deposits. The final result is a map describing the likelihood of an illegal waste deposit to be located at any arbitrary location. Such a probability map is then used together with remote sensing techniques to narrow down the set of possibly contaminated sites (Silvestri and Omri, 2008), which are candidates for further analyses and field investigations. The importance of the integration of GIS and remote sensing is highlighted and represents a key instrument for environmental management and for the spatially‐distributed characterization of possible uncontrolled landfill sites. 相似文献
65.
抛光花岗岩的二向反射比与偏振度的波谱关系 总被引:1,自引:0,他引:1
传统遥感定义双向反射率分布函数(BRDF)的概念,用以表达目标物空间反射的多角度分布特征,但其测量多偏重于单波长的微波及激光。偏振伴随多角度探测而生,蕴涵了目标物的自身特性。该文就城市常见地物——抛光的花岗岩,分别测量了其在350~2 500nm范围内的二向反射比和偏振度的波谱,分析并比较了两者波谱随探测角度的变化规律,并从定义上分析了两者的波谱关系,发现其随探测天顶角及方位角的变化规律一致,而且二向反射比和偏振度的波谱在一定程度上呈反比关系。 相似文献
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67.
用正交试验等方法优选壳聚糖生产中脱钙、脱蛋白质、脱乙酸基等工序的工艺条件。试验结果表明:用体积分数为3%的HCl脱钙15h可使制品的灰分含量<1%;用质量分数为8%的NaOH煮沸90min脱蛋白质,可使制品总氮含量<7%;在碱质量分数为42%、物料与碱液配比为1∶40、80℃保温18h的条件下,制品粘度>2000mPa.s.脱乙酰度>80%。 相似文献
68.
Ryan Holifield 《Geoforum》2009,40(3):363-372
A common source of conflict at hazardous waste sites in the US Environmental Protection Agency’s Superfund program is the accuracy of scientific investigations and representations produced to inform cleanup decisions. Liable firms often produce these technical representations themselves, and communities surrounding sites frequently argue that such “voluntary” investigations are compromised by conflicts of interest. In order to challenge the representations of powerful firms, locally situated actors often develop trans-local connections with expertise and equipment concentrated at distant centers of calculation. Although some interpret the spatial politics of such connecting in terms of “jumping scales,” another important spatial dimension of this network construction is differential positioning. In a conflict over groundwater models at the St. Regis Superfund Site in Minnesota, the counter-network that emerged to challenge the owner’s representations of the site positioned some actors as “outsiders” and others as “insiders.” This differential positioning enabled the counter-network to balance the need to demonstrate the reliability and impartiality of its claims with the requirement to maintain its accountability to local public interests. I argue that these requirements result from the prevalent view of the science-policy interface, which assumes a rigid separation between science and politics. Nonetheless, the conflict over groundwater at St. Regis reveals how at the science-policy interface, speaking for things and speaking for people are thoroughly entangled. 相似文献
69.
The Upper Cretaceous Bordighera Sandstone of NW Italy is a coarse-grained, sand-rich elongated turbidite system (ca. 15 × 45 km in outcrop) up to 250 m thick, interpreted to have been deposited in a trench setting. The siliciclastic succession interfingers with muddy calcareous turbidites, which become more abundant toward the lateral and distal domains. Bed type associations allow the distinction of a proximal channelized domain which transitions to a more distal lobe domain, characterized by abundant mudclast-rich sandstones and by bipartite and tripartite beds with a mud-rich middle or upper division (hybrid event beds). The transition between the proximal and distal domains occurs over a relatively limited spatial extent (ca. 5 km). The presence of lenticular bed-sets made up of coarse grained and mud-poor sandstones throughout the distal domain suggests that distributary channels were present, indicating sediment bypass further down-dip toward the most distal and not preserved parts of the system. Hybrid event beds - commonly associated with distal and marginal fan environments such as fan fringes - are present throughout the lobe domain and extend for up to ca. 30 km in down-dip distance. They are more abundant in the proximal and axial depositional lobe domain and their appearance occurs within a short basin-ward distance from the inferred channel-lobe transition zone. Flow expansion at the termination of the channelized domain and the enhanced availability of cohesive substrate due to the presence of intra-basinal muddy calcareous beds are interpreted as the key controls on the widespread occurrence of mudclast-rich and argillaceous sandstone beds. The abrupt appearance and the persistent occurrence of such beds across an extensive domain have implications for characterizing bed-scale (sub-seismic) heterogeneity of deep-water clastic hydrocarbon reservoirs. 相似文献
70.
在分析了顾客的要求结构基础上,逐步确定了顾客满意指标和顾客满意级度,并且对收集顾客满意信息的方式、内容及渠道提出看法及改进措施。 相似文献