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Workshop on Abundance Estimation   总被引:1,自引:0,他引:1  
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Summary. Mauldon (1998) suggested end-point estimators of areal frequency and mean trace length for a planar sampling window which were recently proved to be unbiased maximum likelihood estimators by Lyman (2003). The present paper is to expand the concept and applicability of the end-point estimators to those for a general non-planar sampling window. The generalized end-point estimators are verified and its applicability for variable discontinuity orientation is checked by Monte Carlo simulation. Standard deviation of estimation error and estimation efficiency of areal frequency and mean trace length are also considered.  相似文献   

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地貌单位线(GIUH)基于流域地貌特征和概率方法,在我国许多地区得到广泛应用。针对面雨量分布不均问题,通过分析初始概率的变化,考虑GIUH的非线性改正,并用实际资料进行了验证。  相似文献   

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Conclusion Many elements contributed to the urban expansion of Shanghai, but port expansion, industrial growth, population change and construction of new housing quarters were the main. Moreover, they were interdependent and interactive. This article summarizes these influences, on urban spatial expansion in Shanghai. It will be helpful in further approaches to this issue.  相似文献   

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从弹性半空间Boussiuesq解出发,采用有限元法和压缩层地基模型,探索计算厚筏基础倾斜值的方法,计算厚筏基础的不均匀沉降和倾斜值,并利用工程实例进行说明,计算结果与实测结果较吻合。  相似文献   

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Areal reallocation of China's water resources   总被引:1,自引:0,他引:1  
Changming Liu  Wei Du 《GeoJournal》1985,10(2):157-162
This paper mainly deals with the following aspects: (1) the necessity of water transfer; (2) major schemes proposed for water diversions and (3) some environmental assessments in the eastern route project.  相似文献   

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区域蒸散发量的气候学计算方法   总被引:6,自引:0,他引:6  
冯国章 《水文》1994,(3):7-11
本文介绍了一种计算区域蒸散发量的气候学方法。本法应用Bouchet区域蒸散发互补关系概念,以陕西省55个流域或区间的常规地面气候观测资料为基本输入,建立了区域蒸散发互补关系模型。该模型具有计算成果合理,精度较高,适应性广等特点。  相似文献   

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雷达-雨量计联合校准降水结合了雷达区域覆盖和雨量计单点精度高的优势, 利用雷达进行区域降水量估计是提高雷达应用能力的重要方向之一. 通过利用在青藏高原东北边坡地区的雷达回波-降水反演关系式, 对2012年5月10日的这一地区的一次区域性强降水过程进行反演比较, 并利用平均校准法、 最优插值法和用卡尔曼滤波确定变分系数的变分-卡尔曼滤波进行空间校准. 结果表明:利用最优化法得到的本地降水反演关系式效果要明显优于其他波段或地域的固有关系式, 可以有效改变过低估计的状况; 变分-卡尔曼滤波由于考虑了雷达区域扫描的优势, 校准效果最好, 可以细致反映空间降水分布, 对降水预报、 地质灾害预警等都有重要意义.通过建立多仰角多变量的降水关系式, 并进一步对反演结果采用有效的数学校正法可能会对空间面雨量估测取得更好的效果.  相似文献   

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肖玲  宋松柏 《水文》2013,33(6):1-5
研究基于高阶概率权重矩的广义极值分布参数估计。根据高阶概率权重矩法原理,建立了广义极值分布高阶概率权重矩估算参数模型。以陕北地区4个水文测站的年最大洪峰流量序列为例,结果表明:高阶概率权重矩法能赋予大洪水值更多的权重。蒙特卡洛试验表明:适当提高阶数可以减小误差,但阶数过高反而会增大误差。  相似文献   

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基于可持续发展的区域水资源多目标优化配置研究   总被引:2,自引:0,他引:2  
罗利民  仲跃  张晟  谢能刚 《水文》2006,26(4):6-9
以区域经济发展与水环境保护相协调为目标,考虑社会各产业经济部门的污水处理和节水调节的控制作用,建立水资源多目标优化配置模型,并利用模糊理论构建评价函数。通过应用于盐城市水资源的优化配置,计算分析结果表明该方法具有良好的可行性和合理性。  相似文献   

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中国暴雨面雨量极值分布   总被引:2,自引:1,他引:2       下载免费PDF全文
研究了暴雨面积、面平均雨深、暴雨降水总量等有关面暴雨量极值的主要内容;给出了最大时面深记录等各种雨量极值;探讨了面暴雨极值的地域分布规律和影响因素。  相似文献   

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Lithology and Mineral Resources -  相似文献   

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The achievements of the mineral industry of Israel and an overall reconnaissance of the natural resources endowment of the country have been evaluated by the areal value estimation method, using the COMOD software package. In broad terms, the evaluation relies on geological variables obtained from quantifying the geological map of a region and on cumulative past production records, which, when prorated per unit area, yield a series of unit regional values (u.r.v.)measurements for individual commodities, resource sectors, and total resources. The two groups of variables facilitate conducting comparisons with other well-developed and/or geologically similar regions from which the future potential of the region, with respect to both overall endowment and individual commodities, can be assessed. The model underlying this appraisal method assumes that all regions above a size of about 5,000 sq kms are equally valuable with respect to total endowment in natural resources, regardless of inherent geological characteristics. To date, several areal value estimation studies have been carried out for 11 different countries, encompassing a total of 111 politically-administratively defined regions. These studies provide an adequate information base for between-region comparisons. The individual states of the United States, constituting what can be regarded as well-developed regions, may serve as an expectation for all such comparisons. The distribution of the u.r.v. of total resources of the individual states is lognormal with a geometric mean of 54,954 1967 U.S. dollars per square kilometer. Based on the above assumption, this value can serve as a conservative estimate for the total output any region can be expected to produce. Thirty different mineral commodities are known to exist in Israel. Of these, 19 are economically exploited and the remaining 11 are at present uneconomical mineral occurrences. Past production records have been obtained and assembled for 14 of the exploited commodities. From these records, a number of statistics were computed to evaluate the development of the mineral industry of the country and its future potential. In absolute figures, the overall cumulative production has been rather small, amounting to only 1,679.8 million deflated 1967 U.S. dollars (equivalent to 2,082 million current U.S. dollars or 10,260 million current Israeli pounds). Only bromine, potash, and phosphate are of worldwide significance, amounting respectively to 10, 2.9, and 1 percent of the world production in 1977. Construction materials, with the longest production history, have been the most valuable, accounting for 53.6 percent of the total cumulative output. They are followed by nonmetals (34.7 percent),metals (8 percent)and fuels (3.7 percent).The value-ranking of individual commodities and their respective contribution to the total cumulative output is: cement, 35 percent; potash, 19 percent; stone, 15 percent; phosphate, 11 percent; copper, 8 percent; sand and gravel, 4 percent; bromine, 3 percent; petroleum, 2.5 percent; natural gas, 1 percent; periclase, 0.7 percent; salt, 0.4 percent; and glass sand, 0.2 percent. Total annual output for the period 1948–1977 exhibited a constant growth with no indication of approaching a plateau of diminishing returns. As new commodities became exploited, the share of constructional materials in the total output gradually declined from 100 percent in 1948 to 45 percent in 1977. The contribution of the mineral industry to the annual gross national product rose steadily from 0.55 percent in 1951 to 2.2 percent in 1964. Thereafter, it fluctuated around an average of about 1.8 percent. Total output and production of constructional materials correlate very highly with both gross national product (GNP)and population size. However, when only the annual changes in these variables are considered, the correlation coefficients are found to be insignificant. The u.r.v. of Israel (with an area of 20,700 sq kms and a population of 3,653,000)is 81,154 deflated 1967 U.S. dollars per sq km. It exceeds the expected value for well-developed regions. It can therefore be concluded that Israel is not exceptionally poor in natural resources, as is commonly felt. On the other hand, its high u.r.v. also implies (unfortunately)that the development potential of its mineral industry is rather limited. The u.r.v. estimates, which are based on area alone, can be refined to some degree by considering the geological characteristics of the investigated area. The geological composition of the country was quantified by point counting the geological map, using a grid network of 40.3 sq km cells. Each map unit was assigned to one of 65 standard time-petrographic units. This sampling density results in the recognition of 11 time-petrographic units (instead of 15, which are actually present).Based on linear statistical association between mineral resource diversity and geological diversity established for the states of the United States, Israel can be expected to possess 31 different commodities. Since only 19 have thus far been exploited, Israel can be expected to produce 12 additional commodities. The identity of these missing resources can be inferred by examining the inventory of commodities produced in other regions with a similar geological framework and by evaluating the potential of the 11 noneconomical mineral occurrences, which have already been discovered in the country. The geology of Israel was compared to 12 other regions; of these Egypt, Libya, Sudan, and Sinai were found to be most similar to Israel, each having 8 or 9 time-petrographic rock types in common with Israel, 7 of which are identical. Based on these comparisons and on additional information from other sources, it appears that the commodities that are more likely to be produced in the foreseeable future include manganese, feldspar, uranium (from phosphates),lignite, oil shale, and iron. The mineral industry of Israel accomplished quite significant achievements in the course of its modern history of only 35 years. These resulted from concerted national exploration and development efforts, which were supported by massive governmental capital investments. The areal value method of mineral resources appraisal is based on a cybernetic black box system model in which the degree of commitment derived from the socioeconomic infrastructure is viewed as the driving agent in converting the inherited geological characteristics of the region into economic marketable mineral commodities. The case history of Israel provides a strong substantiation for this generalized system model.  相似文献   

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