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1.
Some karst regions of Indonesia (Java, Sulawesi, Bali, Madura), on closer examination geomorphologically and hydro-geologically quite distinct from each other, are checked with regard to land-use, settlement and other economic and cultural significance. Brief comparisons are made to similar regions from the Philippines (Bohol), Thailand etc. An amazingly strong differentiation, especially of the rice-cultivation systems, is determined by the varying access to water. Some densely populated limestone regions are suffering even from critical water supply for human consumption, cattle etc. Proposals for improvement and rural development are given. The comparison of agricultural landscape types under changing geo-ecological conditions yield fine examples of closely interwoven man-earth eco-systems.  相似文献   

2.
基于经济区域分析层次,采用多区域投入产出分析法、锡尔指数空间差异分解与伪基尼系数差异成因分解方法,探寻我国水足迹总量、部门结构及相关指标的经济区域间和区域内省区间异同点及差异成因,并列出我国特色水安全保障体系构建中有必要调整用水的地区。结果表明:(1)经济区域间和区域内省区间差异对中国水足迹总体空间差异的贡献率相差甚微。(2)西北、中部、西南区域水足迹高于中国其他区域,农林牧渔业人均水足迹、人口数量区域间差异是水足迹经济区域间差异的主要成因;北部沿海区域和西北区域的第一产业水足迹、其他区域的食品制造及烟草加工业水足迹,是当地水足迹重要组成部分。(3)中国各经济区域内水足迹省区间差异的最主要贡献因子存在一定异同,这些因子本身均主要源于其对应部门人均水足迹省区间差别;各省区水足迹部门结构有所异同。(4)东北区域(尤其黑龙江)、京津区域(尤其天津)、山东、上海、海南、宁夏、重庆、山西“很有必要”调整用水,而北部沿海区域(不含山东)、东部沿海区域(不含上海)、西北区域(不含宁夏)、云南、江西调整用水的必要性次之。  相似文献   

3.
Water resources in northern Cameroon have continuously been reducing over the past years. Many studies have suggested two principal causes: (1) human activities such as poor farming practices, unsustainable use of water resources, increased demand of water, deforestation, land-use change, etc., (2) human-induced climate change. Northern Cameroon in this study includes: the Adamawa, North and Far North regions located closer to the Sahel regions of Africa. These regions are already water stressed because of their location and any further change in climate with rising temperature would impact water resource either positively or negatively. Time series analysis and a 12-month standardized precipitation index (SPI12) with digital data between 1957 and 2006 were used to investigate the variation of water resources in northern Cameroon. Results obtained varies between the different regions with an increased annual trend in temperature and precipitation for Ngaoundere (Adamawa region) and Garoua (north region), whereas Maroua (far north region) had a decreased annual trend in both precipitation and temperature. Further variability results obtained from a SPI12 show that wetter period out number drought period in all three regions. The study concluded that water resources vary with the changing climatic condition and the severity of the impact varies from region to region. Furthermore, water deficiency in northern Cameroon might not be due to climate change. The reasons might be a combination of poor water management and other factors such population growth, the environmental condition, etc.  相似文献   

4.
我国干旱区生态需水若干问题评述   总被引:7,自引:0,他引:7  
刘桂民  王根绪 《冰川冻土》2004,26(5):650-656
生态需水是当前水问题研究中的一个热点问题,对于生态环境急剧恶化的我国内陆干旱区,这一研究尤为紧迫.目前生态需水尚无明确统一的定义,研究方法也因人而异.归纳了已有的生态需水的相关概念和干旱区生态需水研究的主要成果、研究方法等.从概念主体角度,区分了生态需水、环境需水、生态环境需水之间的关系,并对  相似文献   

5.
多年冻土路基的稳定性很大程度上取决于其下伏多年冻土层的热稳定性. 当融雪、降雨或人为等外界因素形成的路基坡脚积水持续一段时间后,这些积水可能通过入渗对流换热、热边界侵蚀、补给冻胀水分等方式加剧或诱发多年冻土路基热稳定性的下降和丧失. 通过回顾国内外相关文献,从影响多年冻土路基稳定性的因素、积水对路基活动层冻融过程中水分迁移的影响、热融湖塘类积水对冻土路基的热影响、降雨和融雪积水入渗对冻土路基的热影响等方面,归纳总结了坡脚积水对多年冻土路基影响方面的研究进展;在此基础上,提出了对此问题进一步深入的研究展望和探讨.  相似文献   

6.
寒区环境中的古DNA分子   总被引:1,自引:0,他引:1  
林清  程国栋 《冰川冻土》2002,24(6):812-818
寒区埋藏环境常年处于负温条件下,土壤冻结或冰的形成过程产生封闭作用,可以隔离造成埋藏生物遗体同DNA氧化分解的氧气之间的接触.由于液态水含量极大地减少和冰胶结作用,使得主要依赖于液态水而发生的生物大分子的化学分解以及生物降解反应作用减慢,有机体没有成岩过程中降解以及水解作用,从而使古DNA分子可以得到较好的保存.目前绝大多数关于古DNA研究的重要成果所使用生物材料均来自寒区环境,最为引人注目的有关猛犸象、棕熊和企鹅化石古DNA的研究.这些研究分别从个体、种群和同一种群在不同时间尺度上描绘了它们与现代生物种之间的亲缘关系、过去发生的生物迁移和空间隔离以及特定生物分子水平上的时间演化.从目前来看,大量的生物标本很好地保存在那里,以至于单一考贝基因都可以获得,因此是获取古DNA并获得相应遗传信息的理想地区.  相似文献   

7.
8.
This paper briefly presents the research progress of the State Major Basic Research Project 2001CB309400, “Theory and Application for Retrieval and Fusion of Spatial and Temporal Quantitative Information from Complex Natural Environment”. Based on the rapid advancement of synthetic aperture radar (SAR) imagery technology, information theory of fully polarimetric scattering and applications in polarimetric SAR remote sensing are developed. To promote the modeling of passive microwave remote sensing, the vector (polarized) radiative transfer theory (VRT) of complex natural media such as inhomogeneous, multi-layered and 3-dimensional VRT is developed. With these theoretical progresses, data validation and retrieval algorithms for some typical events and characteristic parameters of earth terrain surfaces, atmosphere, and oceans from operational and experimental remote sensing satellites are studied. Employing remote sensing, radiative transfer simulation, geographic information systems (GIS), land hydrological process, and data assimilation, the Chinese land data assimilation system (CLDAS) is established. Towards the future development of China’s microwave meteorological satellites, employing remote sensing data of currently available SSM/I (special sensor microwave/imager), AMSU (advanced microwave sounding unit), MTI (microwave temperature imager), etc., with ground-based measurements, several operational algorithms and databases for atmospheric precipitation, water vapor and liquid water in clouds, and other hydrological/hydrological applications are developed. To advance China’s SAR and InSAR (interferometric SAR) technologies, the image processing and analysis of ERS (European remote sensing), Radarsat SAR, and Chinese SAR, etc., the software platforms are accomplished. Based on the researches of multi-information fusion, some simulations, identification, and information extractions of the targets from complex background clutter scenes are studied. Some experiments of radio wave propagation in anomalous atmospheric status are also carried out. Translated from Advances in Earth Science, 2007, 22(2): 111–125 [译自: 地球科学进展]  相似文献   

9.
Identifying and quantifying urban recharge: a review   总被引:12,自引:1,他引:12  
The sources of and pathways for groundwater recharge in urban areas are more numerous and complex than in rural environments. Buildings, roads, and other surface infrastructure combine with man-made drainage networks to change the pathways for precipitation. Some direct recharge is lost, but additional recharge can occur from storm drainage systems. Large amounts of water are imported into most cities for supply, distributed through underground pipes, and collected again in sewers or septic tanks. The leaks from these pipe networks often provide substantial recharge. Sources of recharge in urban areas are identified through piezometry, chemical signatures, and water balances. All three approaches have problems. Recharge is quantified either by individual components (direct recharge, water-mains leakage, septic tanks, etc.) or holistically. Working with individual components requires large amounts of data, much of which is uncertain and is likely to lead to large uncertainties in the final result. Recommended holistic approaches include the use of groundwater modelling and solute balances, where various types of data are integrated. Urban recharge remains an under-researched topic, with few high-quality case studies reported in the literature. Electronic Publication  相似文献   

10.
地幔中水的存在形式和含水量   总被引:3,自引:0,他引:3  
水以含水变质矿物、无水硅酸盐矿物(橄榄石、辉石等)及其高压结构相(β橄榄石、γ橄榄石、钙钛矿相、方镁铁矿等)、高密度含水镁硅酸盐和熔体的形式存在于地幔各层圈中。根据各类玄武岩水含量推断出的上地幔源区的水含量,和由地幔岩主要矿物———橄榄石的水含量估算出的上地幔水含量(质量分数)很接近,在0.02%左右。以橄榄石和辉石高压相的水含量为依据,进行了过渡带和下地幔水含量的估算,其结果是:过渡带和下地幔上部的水含量(质量分数)为1.48%,下地幔下部水含量(质量分数)为0.21%。据此,计算出的地幔各层圈的总水量表明,地幔水的74%以上存在于过渡带和下地幔上部。将地幔总水量和现代海洋总水量之和作为地球总水量,计算出现代海洋总水量约占全球总水量(质量分数)的6.6%,这个结果与笔者根据地球的球粒陨石成分模型计算出的总水量(6%)十分接近。  相似文献   

11.
Roy BK 《GeoJournal》1990,20(3):271-284
In this paper an attempt is made to present some facets of status of water for agriculture and population in India. The issues are basic in nature which have been focused by scholars all over time and again. The materials are gathered from various sources to highlight and to consider a plea in the context of population-hydrological regions of the country to develop water potentials. Some characteristic mapping has also been conducted showing the main parameters of water utilization, need and spatial issues regarding consumptive use of water during agricultural operations as per the seasons prevalent in India. A relation is also established with the drought areas leading to assess the need for water. The human problems specially in relation to the safe drinking water is also projected in relation to distributional qualities with reference to natural regions by districts. The study does not claim a full assessment of the water issue due to paucity of statistics on water use, generation and potentials but it does indicate in many ways the geographical problems as an important study for further research by all concerned.  相似文献   

12.
长江中游瓦口子至马家咀河段二维水沙数学模型   总被引:1,自引:6,他引:1       下载免费PDF全文
针对长江中游瓦口子至马家咀河段(弯曲分汊河段)的水沙运动特点,给出了二维水沙数学模型尤其是推移质不平衡输沙计算的模式,主要包括推移质不平衡输沙方程、床沙级配方程、河床变形方程;对模型中的几个关键问题提出了处理方法,如非均匀沙起动及输移规律、床面混合层厚度等.利用大量的水流及河床变形资料,率定了模型的一些参数,进行了水面线、流速分布及河床变形的详细验证.在此基础上,根据设计部门提供的进出口水沙边界条件,预测了三峡工程蓄水初期该河段的冲淤过程与分布及航道条件的变化.  相似文献   

13.
A study of the mineralogy of some Laxfordian shear zones atScourie shows that they formed at about 600 °C, 6 kb, andwere zones of intense metasomatism. The gneisses in the shearzones have been enriched in potash and water, depleted in calciumand silica and oxidized relative to underformed gneisses adjacentto the shear zones. Microprobe analyses of the phases presentin the shear zones are used to write chemical reactions describingthe formation of new phases (biotite, kyanite, etc.) from pre-existingphases (pyroxene, horn-blende, garnet, etc.). Some kyanite-sillimanite-staurolite-corundum-spinel-bearingassemblages are described in detail since these provide themost definitive P–T indicators.  相似文献   

14.
Stream water composition, measured weekly for 8–9 months in 1994 in three arctic catchments on and around the Kola Peninsula (Russia, Finland and Norway), is presented in the form of time-series. In all three catchments, snowmelt causes a major dilution of the stream water, as reflected by marked dips in electrical conductance. In the most polluted catchment (C2), the snowmelt flood (the major hydrological event at these latitudes) is reflected in the stream water by a pH dip and a pulse in technogenic heavy metals (Cu, Ni, etc.), Al and S. This results from melting of the snow laden with heavy metals and sulphate, and from leaching of the topsoil layer. In the most pristine catchment (C8), snowmelt causes no heavy metal pulse (remote location) but yields an increase in stream water Al (acidic lithology/overburden). In the intermediate catchment (C5), very subdued heavy metal and S increases are noticeable in the stream water, whilst its pH increases steadily until summer (basic lithology). Some elements (Cl, S) may be mobilised out of the snowpack before its complete thawing and reach the stream 1–2 weeks ahead of the heavy metals. The substrate (soil, overburden and bedrock) of a catchment controls to a large extent its ability to buffer acid inputs.  相似文献   

15.
Molecular and supermolecular structures of fossilized resins from the North Eurasia have been studied in detail by IR-spectroscopy, atomic force microscopy (AFM), scanning (SEM), and high-resolution transmission electron (HRTEM) microscopy. The analysis of the IR-spectroscopy data allowed to identify the types of the fossil resins (succinite, rumanite, retinite, etc.). In the succinites and rumanite, the supermolecular structure was observed by AFM. Sizes of the supermolecular particles are 50–120 nm. Some chain-like and cluster-like aggregates can be observed when globules contact with each other. Using SEM and HRTEM techniques, it has been shown that mineral impurities are mainly located as scattered inclusions (from one nanometers up to several tens micrometers in size) in an amorphous organic matrix of the resin.  相似文献   

16.
南水北调中线工程前期工作成果信息系统技术开发   总被引:1,自引:0,他引:1       下载免费PDF全文
吴畏 《水科学进展》1999,10(4):418-423
介绍了南水北调中线工程前期工作成果信息系统在Intranet环境下开发的主要技术方案、系统开发和管理技术、网络建设、系统开发环境和工具等内容,探讨了实现类似系统开发的若干关键技术.  相似文献   

17.
陕西是我国金矿资源和产金量的大省之一。本文从金矿资源分布、矿床规模、类型、品位、成矿期、控矿条件、开采条件以及矿石的可选性能、资源保证程度等10个方面对陕西金矿的特点进行了剖析,为金矿找矿、采冶的决策提供了一些可供透视和挖掘的信息。  相似文献   

18.
Prediction of water quality from simple field parameters   总被引:2,自引:0,他引:2  
Water quality parameters like temperature, pH, total dissolved solids (TDS), total suspended solids (TSS), dissolved oxygen (DO), oil and grease, etc., are calculated from the field while parameters like biological oxygen demand (BOD) and chemical oxygen demand (COD) are interpreted through the laboratory tests. On one hand parameters like temperature, pH, DO, etc., can be accurately measured with the exceeding simplicity, whereas on the other hand calculation of BOD and COD is not only cumbersome but also inaccurate many times. A number of previous researchers have tried to use different empirical methods to predict BOD and COD but these empirical methods have their limitations due to their less versatile application. In this paper, an attempt has been made to calculate BOD and COD from simple field parameters like temperature, pH, DO, TSS, etc., using Artificial Neural Network (ANN) method. Datasets have been obtained from analysis of mine water discharge of one of the mines in Jharia coalfield, Jharkhand, India. 73 data sets were used to establish ANN architecture out of which 58 datasets were used to train the network while 15 datasets for testing the network. The results show encouraging similarity between experimental and predicted values. The RMSE values obtained for the BOD and COD are 0.114 and 0.983 %, respectively.  相似文献   

19.
中国水系的盒维数及其关系   总被引:15,自引:2,他引:13       下载免费PDF全文
应用分形理论,系统地探讨了整个中国水系及其各组成流域水系的分形结构特征。通过研究,得出主要结论如下:(1)整个中国水系及其各组成流域水系的分形结构特征是客观存在的;(2)应用网格法系统地计算出了中国各流域水系的盒维数值:整个中国水系的盒维数值为1.4189,中国外流区水系的盒维数值为1.4305;(3)中国平原地区水系的盒维数值一般较大;(4)整个中国水系盒维数值与组成它的各个层次流域水系的盒维数值的平均值并不相等,一般而言,不同层次流域水系盒维数值的平均值小于整个水系盒维数值。  相似文献   

20.
Use of numbers on maps and diagrams would eliminate the ambiguity arising from use of essentially meaningless terms, e.g. “widespread” (i.e. 10% to 90% of something), “much,” “little,” and others. Quantitative characterizations of geologic-lithologic sections, numerical expressions of mineral commodity reserves on maps, etc are entirely justified by the abundance of such data as exemplified by the Altay-Sayan regions and by other U.S.S.R. territories. -- V.P. Sokoloff.  相似文献   

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