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101.
遥感旱灾模型综合分析 总被引:8,自引:0,他引:8
本文在野外实验的基础上,对遥感旱灾模型进行综合分析和评价。运用四年的实地观测数据,校正了旱灾模型中的待定系数,使其能用于NOAA气象卫星对旱情的监测。对复杂的蒸散模型简化的可行性进行了尝试性研究。 相似文献
102.
As a result of the '16-year drought' that Burkina Faso experienced from the late 1970s to the mid-1980s, there has been significant
movement of people from the north of the country to the south. The large numbers of people that were displaced as a result
of this natural disaster put pressure on the production systems of the south and caused concern amongst development organisations
that environmental degradation would follow. Through a 2-year research period, using participatory approaches, it was found
that despite a doubling of the population and the introduction of foreign production systems, the process of communal land
control has significantly limited environmental degradation. This paper explains how customary law has controlled the settlement
of immigrants (the Mossi and Fulani) and how it has overseen land allocation in three villages. The conclusions of the study
indicate that, firstly, the customary law mechanisms in the three villages are effective in addressing communal resource use
and, secondly, there is an evolution in customary law systems as they respond to local change.
Received: 24 February 1999 · Accepted: 15 May 1999 相似文献
103.
长江中下游地区旱涝气候年景和评定方法的研究 总被引:5,自引:0,他引:5
采用经过修改的Z值指标,利用1961~1995年5~9月的总降水量,建立了长江中下游地区7省市逐年的旱涝等级序列;同时通过计算干旱指数、洪涝指数和旱涝综合指数,对长江中下游地区的旱涝和旱涝气候年景进行了评定,初步实现了气候年景评定从定性向定量的转变,并得到一致的可比的历史序列。 相似文献
104.
灾害等级的灰色聚类分析 总被引:20,自引:0,他引:20
灰色聚类分析是灾害等级研究的一种简单易行的方法。本文利用灰色聚类分析的原理和方法来确定灾害的等级归属问题,避免了人为判断中的主观任意性,从而使等级归属问题由定性判断推进到定量计算 相似文献
105.
洪水的等级划分及其减灾意义 总被引:11,自引:3,他引:11
根据地震,风力等级的数学结构,提出一种洪水等级划分公式;对用等级表示洪水大小的减灾意义作了初步分析。 相似文献
106.
1994年,中国出现了大范围的反常气候,给社会经济和人民生命财产带来严重的损失。本文就洪涝、干旱、热带气旋、高温酷热等四种主要气象异常事件及其影响进行了较详细的描述和分析。 相似文献
107.
Kent M. McGregor Glen A. Marotz Donald O. Whittemore 《Journal of the American Water Resources Association》1988,24(1):43-48
ABSTRACT: Drought affects the quality of ground water in certain aquifers used by municipalities in Kansas. Water quality changes occur as a function of the amount of water available for recharge and hence to dilute more mineralized ground waters. Several measures of meteorological drought, including the Palmer Index and Eagleman Aridity Index, were correlated with water quality data to determine the degree of association. Several locations showed sharp delinces in water quality as the drought progressed. These relationships can be used to predict possible variations in present and future well-water supplies in locations subject to drought induced water quality deterioration. 相似文献
108.
109.
电子安全监控系统(PES)失效与控制 总被引:1,自引:5,他引:1
刘铁民 《中国安全生产科学技术》2005,1(6):10-14
随着电子安全监控系统(PES)的日益广泛应用,其系统自身的安全保护已成为安全科技最前沿的问题之一.本文论述了PES在安全系统中的主要应用领域,分析了PES出现故障和失误的原因主要分为硬件故障、系统失误和管理缺陷三大类,提出了建立PES安全保护系统的技术路线和提高系统可靠性的技术措施.建议我国从标准化的角度深入开展电子安全监控系统的安全性研究. 相似文献
110.
Naumburg E Mata-Gonzalez R Hunter RG McLendon T Martin DW 《Environmental management》2005,35(6):726-740
Although changes in depth to groundwater occur naturally, anthropogenic alterations may exacerbate these fluctuations and, thus, affect vegetation reliant on groundwater. These effects include changes in physiology, structure, and community dynamics, particularly in arid regions where groundwater can be an important water source for many plants. To properly manage ecosystems subject to changes in depth to groundwater, plant responses to both rising and falling groundwater tables must be understood. However, most research has focused exclusively on riparian ecosystems, ignoring regions where groundwater is available to a wider range of species. Here, we review responses of riparian and other species to changes in groundwater levels in arid environments. Although decreasing water tables often result in plant water stress and reduced live biomass, the converse is not necessarily true for rising water tables. Initially, rising water tables kill flooded roots because most species cannot tolerate the associated low oxygen levels. Thus, flooded plants can also experience water stress. Ultimately, individual species responses to either scenario depend on drought and flooding tolerance and the change in root system size and water uptake capacity. However, additional environmental and biological factors can play important roles in the severity of vegetation response to altered groundwater tables. Using the reviewed information, we created two conceptual models to highlight vegetation dynamics in areas with groundwater fluctuations. These models use flow charts to identify key vegetation and ecosystem properties and their responses to changes in groundwater tables to predict community responses. We then incorporated key concepts from these models into EDYS, a comprehensive ecosystem model, to highlight the potential complexity of predicting community change under different fluctuating groundwater scenarios. Such models provide a valuable tool for managing vegetation and groundwater use in areas where groundwater is important to both plants and humans, particularly in the context of climate change. 相似文献