区域火灾风险评估模型研究的理论与实践

首先立足于风险研究这个大背景下,在理论上对风险的概念进行了比较分析。然后针对水灾的风险根据其研究与实践中的侧重点不同,分为“损失可能性”学派、“未来损失”学派以及“损失不确定性”三个学派。在此基础上,分析了水灾风险的不确定性,从而提出了易于概率论和可能性理论的水灾风险定义,并将此定义应用于区域水灾风险评估的模型中。最后,探讨了水灾风险评估研究的问题与对其未来的展望。     

Reflections in a Stock Pond: Are Anthropogenically Derived Freshwater Ecosystems Natural, Artificial, or Something Else?

“A skyscraper is as natural as a bird’s nest” –Alan Watts For millennia, people have altered freshwater ecosystems directly through water development and indirectly by global change and surrounding land-use activities. In these altered ecosystems, human impacts can be subtle and are sometimes overlooked by the people who manage them. This article provides two case studies near Boulder, Colorado that demonstrate how perceptions regarding these ecosystems affect their management. These examples are typical of lakes and streams along the Front Range of Colorado that are simultaneously natural and social in origin. Although natural, many of the region’s freshwater ecosystems are affected by ongoing ecologic, hydrologic, chemical, and geomorphic modifications produced by human activity. People and nature are both active participants in the production of these freshwater ecosystems. The concept of “hybridity,” borrowed from geographers and social scientists, is useful for describing landscapes of natural and social origin. Hybrid freshwater ecosystems are features of the humanized landscape and are derived from deliberate cultural activities, nonhuman physical and biological processes, and incidental anthropogenic disturbance. Our perceptions of “natural” freshwater ecosystems and what definitions we use to describe them influences our view of hybrid systems and, in turn, affects management decisions regarding them. This work stresses the importance of understanding the underlying societal forces and cultural values responsible for the creation of hybrid freshwater ecosystems as a central step in their conservation and management.     

中国科技人才资源区域差异与类型

中国科技人才资源的地区和部门分布具有明显的区域差异.在三大地带间、地区内和各省市间差异程度不同且有扩大趋势,在三个重要部门中配置也表现出明显的地域差异.根据科技人才资源赋存状况及部门配置的区位熵值,将各省市区分成5种类型:科技人才资源高度型、中高度型、中度型、中低度型、低度型,这些区域类型与我国的区域经济发展格局相适应.     

MAPPING REGIONAL PRECIPITATION INTENSITY DURATION FREQUENCY ESTIMATES1

ABSTRACT: For regional precipitation frequency analyses, methods are needed to spatially interpolate or smooth point intensity duration frequency (IDF) estimates at gage sites for the purposes of visualization and estimation at ungaged sites. In this study to update IDF estimates for Michigan, the assumption is made that for practical purposes, the entire state may be treated as a homogeneous region in which annual maximum precipitation is identically distributed at each site apart from a site‐specific scaling factor, commonly known as the index flood. Several interpolation and smoothing techniques are evaluated for IDF estimation at ungaged sites, including trend surface analysis, thin plate splines, inverse distance weighting, and several kriging algorithms. Ordinary block kriging is recommended as a practical and objective method for smoothing the variability in the index flood values and developing isopluvial maps.     

EFFECTS OF BASIN-SCALE TIMBER HARVEST ON WATER YIELD AND PEAK STREAMFLOW1

ABSTRACT: Streamflow changes resulting from clearcut harvest of lodgepole pine (Pinus contorta) on a 2145 hectare drainage basin are evaluated by the paired watershed technique. Thirty years of continuous daily streamflow records were used in the analysis, including 10 pre-harvest and 20 post-harvest years of data. Regression analysis was used to estimate the effects of timber harvest on annual water yield and annual peak discharge. Removal of 14 million board feet of lodgepole pine (Pinus contorta) from about 526 hectares (25 percent of the basin) produced an average of 14.7 cm additional water yield per year, or an increase of 52 percent. Mean annual daily maximum discharge also increased by 1.6 cubic meters per second or 66 percent. Increases occurred primarily during the period of May through August with little or no change in wintertime streamflows. Results suggest that clearcutting conifers in relatively large watersheds (> 2000 ha) may produce significant increases in water yield and flooding. Implications of altered streamflow regimes are important for assessing the future ecological integrity of stream ecosystems subject to large-scale timber harvest and other disturbances that remove a substantial proportion of the forest cover.     

大西南旅游资源的评价与开发

大西南的旅游资源丰富而独特，但开发程度低、经营粗放、发展整体性差、组合效益低．本文根据近年来的研究，从大西南的整体对其旅游资源进行分区及评价、并分析其开发的市场条件，提出了开发途径。     

模糊数学在四川省自然灾害区划中的应用

本文通过对四川省自然灾害分布规律的系统分析,提出其区划的原则和要求,并引入模糊聚类的方法,对四川省自然灾害进行分区划片,目的是为区域规划提供减灾的重点方向。     

GROUND WATER OF THE ISLAND OF MONTREAL,CANADA1

ABSTRACT: The geochemistry and nature of the flow of ground water not only control the supply potential but constitute clues to the whole geology of an area. A study has been made of the largest available assemblage of data from 161 wells for the Island of Montreal collected by the Geological Survey of Canada in 1951–53. Data indicated that the system is generally subartesian, flowing from the principal topographically high areas towards the shores of the Island. As the probable use is about 13% of the estimated recharge of 140 million liters per day, most wells could be supplied by local recharge. The study has confirmed the predominance of calcium bicarbonate ground water from the carbonate sequence. The waters appeared to be saturated with respect to CaCO₃ in all but 10 wells. The presence of other types of waters suggests the effects of the igneous intrusions of the area, the post-glacial marine submergence and the upward movement of waters from deep sources through fault and other structural zones. Confirmation of the significant variations in chemical composition in some neighboring wells indicated the future need for repetitive sampling from specific horizons for chemical and isotopic analyses.     

Ecological land classification: A survey approach

A landscape approach to ecological land mapping, as illustrated in this article, proceeds by pattern recognition based on ecological theory. The unit areas delineated are hypotheses that arise from a knowledge of what is ecologically important in the land. Units formed by the mapper are likely to be inefficient or irrelevant for ecological purposes unless he possesses a sound rationale as to the interactions and controlling influences of the structural components of ecosystems. Here is the central problem with what have been called objective multivariate approaches to mapping based on grid units and the sometimes arbitrary attributes thereof; they tend to conceal the importance of ecological theory and the necessity for theory-based supervision of pattern recognition. Multivariate techniques are best used iteratively to verify and refine map units initially recognized and delineated by theoretical considerations. These ideas are illustrated by an example of a reconnaissance survey in the Northwest Territories of Canada.     

AN EX POST ANALYSIS OF THE UNCOMPAHGRE PROJECT1

ABSTRACT: The national and regional economic impact of the Bureau of Reclamation's Uncompahgre Project which was authorized in 1903 is assessed. Benefit-cost ratios for the project are calculated for a range of production cost estimates and discount rates. An economic base approach is used to estimate the project's regional economic impact. Although the project has been marginal in terms of an economic efficiency rationale it has been an important impetus to regional economic growth in the Uncompahgre Region over time.