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991.
黄河流域水资源价值的计算与分析 总被引:2,自引:0,他引:2
利用经济杠杆的调节作用促使水资源的高效利用,是缓和水资源供需矛盾的有效措施之一。本文以水资源价值理论为基础,从黄河全流域水资源优化配置角度出发,以利用水资源获得最大经济效益为目标,测算了黄河水资源的理论价值,为制定黄河水资源费的征收标准提供科学的理论依据。 相似文献
992.
区域生态环境评价的灰色关联投影模型 总被引:11,自引:0,他引:11
区域生态环境评价是实现全面环境管理,协调区域经济发展与生态环境保护.实现区域可持续发展的重要手段。由于评价所涉及的地域复杂性和因素多样性,许多评价方法和体系都处于不断探索和发展之中。区域生态环境系统是一个灰色系统,包括了自然、经济和社会等方面具有信息不确知性和不完全性的因素。基于灰色系统理论和矢量投影原理,建立了区域生态环境评价的灰色关联投影模型。该模型将评价样本及各级质量标准视为矢量.分别向同一矢量(理想样本)进行投影。根据投影值的大小,确定样本所属的生态环境质量级别及样本间的优劣排序。以巢湖流域为个案,在建立生态环境评价指标体系和标准的基础上,运用所建模型对其生态环境质量现状进行了评价,结果与实际情况相吻合。即巢湖流域总体以及分区合肥市、六安市的生态环境质量为4级,分区巢湖市为5级。研究表明,灰色关联投影模型对于多指标的区域生态环境质量评价是科学的、有效的,具有一定的推广和实用价值。 相似文献
993.
鄂尔多斯周缘地震带中长期地震趋势估计 总被引:2,自引:0,他引:2
本文基于一定的地震资料,分别应用最大熵原理、贝努里概型以及计算地震复发周期的经验关系式,对鄂尔多斯周缘地震带进行了中强地震的中长期地震趋势估计。 相似文献
994.
基于人体皮肤热模型的热防护服评价方法研究 总被引:1,自引:0,他引:1
在热防护服热防护性能测试装置基础上,用自行研制的新型耐高温模拟皮肤传感器代替铜片热流计测量通过应急热防护服装面料的热流量,将热流量作为热波皮肤模型边界条件,得到人体皮肤表层下80μm处的温度值,从而得到一定条件下人体真实皮肤达到二级烧伤所需时间,用其评价热防护服用织物的热防护性能,并将热波皮肤模型(TWMBT)的测试值与Pennes模型以及铜片热流计的测试结果进行分析比较。采用热波皮肤模型分析织物层下的"皮肤"防热时间更接近实际皮肤达到二级烧伤时间值,可较为精确的量化织物热防护性能,为应急救援热防护服装的热设计提供理论依据。 相似文献
995.
可发性聚苯乙烯仓库消防安全评价研究 总被引:1,自引:0,他引:1
对火灾因素多样,且相互间又具有不确定性和模糊性的仓库火灾危险性分析,可应用层次分析法和模糊评价法相结合而形成的一种评价模式。该模式主要通过运用模糊层次综合评价法并结合层次分析法确定各指标的权重分配,对企业安全状况进行评价,经过专家咨询,将各因素层次化,最终得出模糊评价结果。笔者将该模式应用于实例,对可发性聚苯乙烯仓库进行消防安全研究,实例验证了该模式的可行性,并得知该仓库当前的消防安全程度为"临界的",应当采取适当的消防控制措施。通过理论分析和案例应用,证明该方法既能够充分体现评价因素和评价过程的模糊性,又尽量减少个人主观臆断所带来的弊端,更符合客观实际,其评价结果更可信,可靠。 相似文献
996.
David Moncoulon Anne Probst Liisa Martinson 《Water, Air, & Soil Pollution: Focus》2007,7(1-3):307-316
To evaluate the acid deposition reduction negotiated for 2010 within the UNECE LRTAP Gothenburg Protocol, sulphur and nitrogen
deposition time-series (1880–2100) were compared to critical loads of acidity on five French ecosystems: Massif Central basalt
(site 1) and granite (2); Paris Bassin tertiary sands (3); Vosges mountains sandstone (4) and Landes eolian sands (5). The
SAFE model was used to estimate the response of soil solution pH and ratio to the deposition scenario. Among the five sites, critical loads were exceeded in the past at sites 3, 4 and 5. Sites
3 and 4 were still expected to exceed in 2010, the Protocol year. Further reduction of atmospheric deposition, mainly nitrogen,
would be needed to achieve recovery on these ecosystems. At sites 3, 4 and 5, the delay between the critical load exceedance
and the violation of the critical chemical criterion was estimated to be 10 to 30 years in the top soil and 50 to 90 years
in the deeper soil. At site 5, a recovery was expected in the top soil in 2010 with a time lag of 10 years. Unexpectedly,
soil pH continued to decrease after 1980 in the deeper soil at sites 2 and 5. This time lag indicated that acidification moved
down the soil profile as a consequence of slow base cation depletion by ion exchange. This delayed response of the soil solution
was the result of the combination of weathering rates and vegetation uptake but also of the relative ratio between base cation
deposition and acid compounds. 相似文献
997.
Land-use forecasting and hydrologic model integration for improved land-use decision support 总被引:5,自引:0,他引:5
This paper develops a methodology for integrating a land-use forecasting model with an event scale, rainfall-runoff model in support of improving land-use policy formulation at the watershed scale. The models selected for integration are loosely coupled, structured upon a common GIS platform that facilitates data exchange. The hydrologic model HEC-HMS is calibrated for a specific storm event that occurred within central Washington State. The land-use forecasting model, What If? is implemented to forecast future spatial distributions of low-density residential land-uses under low and high population growth estimates. Forecasted land-use distribution patterns for the years 2015, 2025, and 2050 are then used as land-use data input for the calibrated hydrologic model, keeping all other parameters constant. Impacts to the stream discharge hydrograph are predicted as the study area becomes increasingly developed as forecasted by What If?. The initial results of this integration process demonstrate the synergy that can be generated through the linkage of the selected models. The ability to quantifiably forecast the potential hydrologic implications of proposed land-use policies before their implementation offers land-use decision-makers a valuable tool for discerning which proposed land-use alternatives will be effective at minimizing storm water runoff. 相似文献
998.
We present a framework of a scenario-based model that simulates the development of the municipality of Davos (Swiss Alps).
We illustrate our method with the calculation of the scenario for 2050 “Decrease in subsidies for mountain agriculture and liberalization of markets.” The main objective was to link submodels of land-use allocation (regression-based approach), material and energy flows submodels
(Material and Energy Flux Analysis), and economic submodels (Input–Output Analysis). Letting qualitative and quantitative
information flow from one submodel to the next, following the storyline describing a scenario, has proven to be suitable for
linking submodels. The succession of the submodels is then strongly dependent on the scenario. Qualitative information flows
are simulated with microsimulations of actor choices. Links between the submodels show different degrees of robustness: although
the links involving microsimulations are the weakest, the uncertainty introduced by the land-use allocation model is actually
advantageous because it allows one possible change in the landscape in the future to be simulated. The modeling results for
the scenario here presented show that the disappearance of agriculture only marginally affects the region’s factor income,
but that the consequences for the self-sufficiency rate, for various landscape-related indicators and ecosystem services,
and for the economy in the long term may be considerable. These benefits compensate for agriculture’s modest direct economic
value. The framework presented can potentially be applied to any region and scenario. This framework provides a basis for
a learning package that allows potential detrimental consequences of regional development to be anticipated at an early stage. 相似文献
999.
Assessment of the Water Quality and Ecosystem Health of the Great Barrier Reef (Australia): Conceptual Models 总被引:3,自引:0,他引:3
Haynes D Brodie J Waterhouse J Bainbridge Z Bass D Hart B 《Environmental management》2007,40(6):993-1003
Run-off containing increased concentrations of sediment, nutrients, and pesticides from land-based anthropogenic activities
is a significant influence on water quality and the ecologic conditions of nearshore areas of the Great Barrier Reef World
Heritage Area, Australia. The potential and actual impacts of increased pollutant concentrations range from bioaccumulation
of contaminants and decreased photosynthetic capacity to major shifts in community structure and health of mangrove, coral
reef, and seagrass ecosystems. A detailed conceptual model underpins and illustrates the links between the main anthropogenic
pressures or threats (dry-land cattle grazing and intensive sugar cane cropping) and the production of key contaminants or
stressors of Great Barrier Reef water quality. The conceptual model also includes longer-term threats to Great Barrier Reef
water quality and ecosystem health, such as global climate change, that will potentially confound direct model interrelationships.
The model recognises that system-specific attributes, such as monsoonal wind direction, rainfall intensity, and flood plume
residence times, will act as system filters to modify the effects of any water-quality system stressor. The model also summarises
key ecosystem responses in ecosystem health that can be monitored through indicators at catchment, riverine, and marine scales.
Selected indicators include riverine and marine water quality, inshore coral reef and seagrass status, and biota pollutant
burdens. These indicators have been adopted as components of a long-term monitoring program to enable assessment of the effectiveness
of change in catchment-management practices in improving Great Barrier Reef (and adjacent catchment) water quality under the
Queensland and Australian Governments’ Reef Water Quality Protection Plan. 相似文献
1000.
Irfan A. Khan 《Journal of the American Water Resources Association》1979,15(6):1618-1627
ABSTRACT: In projects involving ground water problems, dependence on the mathematical modeling of the ground water flow phenomena is inescapable. At present, two dimensional flow models, which require tremendous amounts of computer time and storage, are generally used. When such bulky models are used for planning purposes, the two requirements (computer time and storage) can severely limit the number of alternatives that can be considered. A simple quantity and quality simulation model is developed here which requires considerably less computer time and storage and gives reasonably accurate results. The model was applied to simulate a ground water basin in San Luis Rey River in Southern California. The results were compared with those obtained by a USGS model. It was found that the simple model gave results which were consistentaly within five percent of the USGS model results, while the requirements on computer time and storage were drastically reduced. 相似文献