洞庭湖流域水生态系统服务功能经济价值研究   总被引：9，自引：2，他引：9  

李景保  常疆  李杨  周亮  喻小红 《热带地理》2007,27(4):311-316

以洞庭湖流域水生态系统为例,在明确河湖库塘生态系统服务功能内涵的基础上,运用生态学与生态经济学方法对洞庭湖流域各类水生态系统服务功能经济价值进行了评估。结果表明,全流域河湖库塘水生态系统服务功能总价值量为1106.19亿元,约占湖南省2004年GDP(5612.26亿元)的19.7%,其中,城镇和农村生活供水、工农业生产供水、水力发电、内陆航运等直接利用价值为415.698亿元;调洪、输沙、水资源贮存等间接利用价值为690.492亿元。可以认为,流域水生态系统服务功能对湖南省工农业生产的持续发展,维系生态环境健康和人民生命财产安全起到了不可替代的支撑和保障作用。  相似文献   

Geographic variations in shell growth rates of the mussel Diplodon chilensis from temperate lakes of Chile: Implications for biodiversity conservation     

Claudio Valdovinos  Pablo Pedreros 《Limnologica》2007,37(1):63-75

The Chilean lake district includes diverse lentic ecosystems along ca. 700 km of the country (36°–43°S), including the “Nahuelbutan lakes”, “Araucanian lakes” and “Chiloe lakes”. This area is recognized as an important “hot spot” of benthic freshwater biodiversity in Southern South America. In Chilean temperate lakes, increased nutrient loads of P and N caused eutrophication, particularly in the Nahuelbutan Lakes. The freshwater Hyriidae mussel Diplodon chilensis (Gray, 1828) which is one of the most abundant species in Chilean temperate lakes, is known to be very susceptible to eutrophication. This species presents a clear reduction in its geographic ranges and is considered to be a threatened species in many Chilean lakes. In this study, we used a correlative approach to determine how eutrophication-driven changes in the food supply and in geographical parameters of different Chilean lakes affected the shell growth rates of D. chilensis. The results obtained from sclerochronological analyses of the mussel shells suggest an association with a group of environmental variables, including geographical types (negative), such as latitude and altitude, and limnological types (positive), especially phosphorous and turbidity. However, the D. chilensis populations under extreme conditions of turbidity in eutrophic and hypertrophic lakes are extinct or nearly so. The high positive correlation of the mean D. chilensis growth rates with orthophosphate (R=0.76; P<0.05), in relation to dissolved inorganic nitrogen, suggests that P is the major limiting factor of the primary productivity in Chilean temperate lakes. We discuss some implications of our results in terms of the conservation of biodiversity in temperate lake ecosystems at different taxonomic levels.  相似文献   

Expected loss‐based alarm threshold set for earthquake early warning systems     

Iunio Iervolino  Massimiliano Giorgio  Gaetano Manfredi 《地震工程与结构动力学》2007,36(9):1151-1168

Earthquake early warning systems (EEWS) seem to have potential as tools for real‐time seismic risk management and mitigation. In fact, although the evacuation of buildings requires warning time not available in many urbanized areas threatened by seismic hazard, they may still be used for the real‐time protection of critical facilities using automatic systems in order to reduce the losses subsequent to a catastrophic event. This is possible due to the real‐time seismology, which consists of methods and procedures for the rapid estimation of earthquake features, as magnitude and location, based on measurements made on the first seconds of the P‐waves. An earthquake engineering application of earthquake early warning (EEW) may be intended as a system able to issue the alarm, if some recorded parameter exceeds a given threshold, to activate risk mitigation actions before the quake strikes at a site of interest. Feasibility analysis and design of such EEWS require the assessment of the expected loss reduction due to the security action and set of the alarm threshold. In this paper a procedure to carry out these tasks in the performance‐based earthquake engineering probabilistic framework is proposed. A merely illustrative example refers to a simple structure assumed to be a classroom. Structural damage and non‐structural collapses are considered; the security action is to shelter occupants below the desks. The cost due to a false alarm is assumed to be related to the interruption of didactic activities. Results show how the comparison of the expected losses, for the alarm‐issuance and non‐issuance cases, allows setting the alarm threshold on a quantitative and consistent basis, and how it may be a tool for the design of engineering applications of EEW. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

斯堪的那维亚臭氧亏损和地面加热     

Zhou Libo  Zou Han  Ji Chongping  Wang Wei  Jian Yongxiao 《大气科学进展》2001,18(3):454-466

对ＮＡＳＡ的ＴＯＭＳ臭氧资料进行分析后指出：冬季在北极的斯堪的那维亚地区存在一个明显的臭氧亏损区，亏损区的中心值达－５０ ＤＵ，相当于该区域平均值的 １５％。对臭氧亏损和北大西洋海温的东西向差异作相关分析得到：其季节变化的相关系数为－０．９６，逐月（ １６８个月）变化的相关系数为－０．７０。同样对臭氧亏损与地面加热进行相关分析后指出：斯堪的那维亚地区的臭氧亏损和该地区地面的热通量关系极其密切，其相关系数均在－０．８７以上。由此我们认为：北大西洋暖流向北输送能量，引起斯堪的纳维亚地区地面加热，由此造成了冬季该地区的臭氧亏损。  相似文献   

矢量数据在多尺度栅格化中的精度损失模型探讨   总被引：14，自引：2，他引：14  

杨存建  张增祥 《地理研究》2001,20(4):416-422

在进行空间分析时,由于栅格数据便于空间分析,因而通常将矢量数据转化成栅格数据进行空间分析。在转化过程中,采用不同尺度的栅格大小会造成怎样的精度损失?精度损失、栅格大小和平均斑块大小之间的关系是否可以用模型来表达?本文正是针对这样的问题,以重庆市1∶10万的土地利用矢量数据为例,探讨了在不同尺度栅格大小(从30m×30m到1000m×1000m)的情况下,各种土地利用类型在转化过程中的精度损失情况,对精度损失与栅格大小和平均斑块大小之间的关系进行了定量分析。研究表明,精度损失与地类的平均斑块大小和栅格尺度之间的关系可以用模型来表达。该模型为:Y=5.366-0.179X-0.978ln(S)+0.0348Xln(S)。模型中Y为精度损失,S为地类的平均斑块大小,X表示栅格的大小。该模型的复相关系数为0.93。  相似文献   

塔里木河水资源利用的效益与生态损失   总被引：13，自引：17，他引：13  

李新  杨德刚 《干旱区地理》2001,24(4):327-331

针对塔里木河流域水资源利用引起的下游水量减少，进而导致生态退化，分析了近30年该河源流区地表水引用和河流水量变化关系，用分摊法估算了水资源利用的直接效益和恢复下游地表径流的恢复费用。  相似文献   

永城煤电集团滤波装置改造的技术经济分析     

艾永乐  康润生等 《中国煤田地质》2001,13(4):67-69

根据对永城煤电集团供电系统中存在的主要谐波情况，翔实分析了其所造成的附加损耗和经济损失。针对永城煤电集团用电负荷造成的谐波现状及现有的固定LC滤波装置的特点，经综合分析最后确定选用TCR型静止动态无功补偿装置与两矿现有的LC滤波装置并联，组成TCR＋FC结构。从技术、经济两方面看，具有重大意义。  相似文献   

Freshwater snail communities and lake classification. An example from the Åland Islands, southwestern Finland     

Ralf Carlsson   《Limnologica》2001,31(2)

The freshwater snail fauna in 51 lakes on the Åland Islands was investigated. By means of cluster analysis it appears that lakes may be divided into four groups on the basis of snail species composition. The lakes of the four groups show a spatial distribution which is related to topographical differences, terrestrial vegetation and land use. Snails may be divided on the basis of water hardness into hard water species and calcium indifferent species or into demanding and modest/indifferent species when clustering is based on presence/absence.  相似文献   

MEASUREMENTS AND MODEL SIMULATIONS OF SURFACE OZONE VARIATIONS AT DIFFERENT BACKGROUND CONCENTRATIONS OF THE PRECURSORS   总被引：1，自引：0，他引：1  

罗超  汤洁  周秀骥 《Acta Meteorologica Sinica》1996,(2)

Ozone photochemical production and loss in very different environments at Waliguan baselinestation and Lin'an background station were simulated by using the measurement data and photo-chemical box model.The results show that net ozone photochemical production rate is negative,about 0.5 ppb/d,at Waliguan baseline sation,because of very low precursor concentrations.Butat Lin'an background station,the net photochemical ozone production is positive,about 2—3 ppb/h.which is very closed with the measurement at Lin'an.That means ozone production was con-trolled by photochemical reactions at Lin'an background station,because of the higher precursorconcentrations.The net destruction rate,at Waliguan Mt.,is not large,so that future increase inanthropogenic emission of reactive nitrogen will lead to larger production rates of steady-state O_3concentration.  相似文献   

1996年上半年世界地震灾害综述     

赵荣国  李卫平 《国际地震动态》1996,(11):11-16

１９９６年上半年全世界共发生６级以上地震５８次，其中７级以上地震１０次，成灾的地震１０次，死亡人数总５１０人，伤约１．５万人，经济损失为８３亿－１００亿元人民币。其中我国境内灾害地震３次，死亡人数共计３４９人，伤约１．４５万人，经济损失约７８亿元人民币。我国因地震死亡的总人数约占全世界地震  相似文献