云南逐月雨量和气温的格点数据资料场建立   总被引：8，自引：2，他引：8  

尤卫红  夏欣健  赵宁坤 《云南地理环境研究》2004,16(1):14-18,32

根据云南各气象台站的逐月雨量和气温观测数据资料,采用距离平方加权平均的格点插值方法,建立了云南(98.0°E～106.0°E、21.0°N～29.0°N)1951年1月～2002年12月0.25°×0.25°经纬度分辨率的逐月格点降水和气温数据资料场。应用该格点数据资料场,分析得到了云南年降水量场和年气温场变化的一些基本空间分布特征和时间演变特征。  相似文献   

Weights of Evidence Modeling of Mineral Potential: A Case Study Using Small Number of Prospects,Abra, Philippines   总被引：9，自引：1，他引：9  

Carranza  Emmanuel John M. 《Natural Resources Research》2004,13(3):173-187

Weights of evidence (WofE) modeling usually is applied to map mineral potential in areas with large number of deposits/prospects. In this paper, WofE modeling is applied to a case study area measuring about 920 km² with 12 known porphyry copper prospects. A pixel size of 100 m × 100 m was used in the spatial data analyses to represent in a raster-based GIS lateral extents of prospects and of geological features considered as spatial evidence. Predictor maps were created based on (a) estimates of studentized values of positive spatial association between prospects and spatial evidence; (b) proportion of number of prospects in zones where spatial evidence is present; and (c) geological interpretations of positive spatial association between prospects and spatial evidence. Uncertainty because of missing geochemical evidence is shown to have an influence on tests of assumption of conditional independence (CI) among predictor maps with respect to prospects. For the final predictive model, assumption of CI is rejected based on omnibus test but is accepted based on a new omnibus test. The final predictive model, which delineates 30% of study area as zones with potential for porphyry copper, has 83% success rate and 73% prediction rate. The results demonstrate plausibility of WofE modeling of mineral potential in large areas with small number of mineral prospects.  相似文献   

利用现有重力场模型求定CHAMP卫星加速度计修正参数   总被引：3，自引：0，他引：3  

徐天河  杨元喜 《测绘学报》2004,33(3):200-204

CHAMP卫星加速度计数据的标定是通过确定其尺度因子和偏差参数来完成的.本文基于能量守恒方程,给出利用现有重力场模型标定CHAMP卫星加速度数据的基本原理和数学模型;提出相邻历元间差分算法,大大简化了观测方程,同时避免积分常量的计算.该算法既能同时解算尺度因子和偏差参数,也可任意求解其中之一.基于实测的CHAMP卫星加速度数据,利用EGM96模型和最新公布的EIGEN-2模型进行计算与比较,验证该方法的有效性.  相似文献   

竖向地震动强度包络函数的空间变化规律          下载免费PDF全文

钟菊芳  胡晓  屈铁军  吴胜兴 《地震工程学报》2005,27(1):42-46

利用SMART 1台阵三次地震记录拟合了各个测点在地震中的竖向地震动强度包络曲线及Amin 和Ang的强度包络函数中各模型参数值,分析了各模型参数的空间变化规律,建立了各模型参数随二维空间坐标及土层厚度变化的随机模型,为多点地震动合成中竖向强度包络函数的计算提供了理论依据。  相似文献   

Histogram and variogram inference in the multigaussian model   总被引：1，自引：4，他引：1  

Xavier Emery  Julián M. Ortiz 《Stochastic Environmental Research and Risk Assessment (SERRA)》2005,19(1):48-58

Several iterative algorithms are proposed to improve the histogram and variogram inference in the framework of the multigaussian model. The starting point is the variogram obtained after a traditional normal score transform. The subsequent step consists in simulating many sets of gaussian values with this variogram at the data locations, so that the ranking of the original values is honored. The expected gaussian transformation and the expected variogram are computed by an averaging operation over the simulated datasets. The variogram model is then updated and the procedure is repeated until convergence. Such an iterative algorithm can adapt to the case of tied data and despike the histogram. Two additional issues are also examined, referred to the modeling of the empirical transformation function and to the optimal pair weighting when computing the sample variogram.  相似文献   

Counting Beans: Agrobiodiversity,Indigeneity, and Agrarian Reform     

J. Anthony Abbott 《The Professional geographer》2005,57(2):198-212

In‐field conservation of locally domesticated crop varieties ameliorates agrobiodiversity losses, but the interaction among nationally regulated socioeconomic factors at the local scale tends to discourage this. Analyses of household surveys conducted in Ecuador demonstrate that state and nongovernmental institutions interact to discourage cultivation of locally domesticated varieties of beans (Phaseolus spp.). Land privatization, agricultural extension, and credit programs favor market production of introduced modern bean varieties, and locally domesticated varieties are noted for favorable nutrition, culinary, and agroecological qualities. Resolving disconnections between the market and social values for landrace beans may provide agrobiodiversity conservation opportunities.  相似文献   

Land tenure type as an underrated legal constraint on the conservation management of coastal dunes: examples from Ireland     

John McKenna  Michael MacLeod  rew Cooper  Anne Marie O'Hagan†  James Power‡ 《Area》2005,37(3):312-323

Legal factors play an underrated but significant role as constraints on conservation management. In this paper, based on observations in both Northern Ireland and the Republic of Ireland, mode of land tenure is assessed to determine its influence on the conservation management of coastal dunes. The tenure types considered are: private ownership, corporate private ownership, tenancy, secured tenancy, leasing, common (joint) ownership, uncertain ownership, public ownership and its subset military ownership. It is suggested that multiple private ownership is least likely to favour effective conservation management. Public ownership by a statutory conservation authority and corporate private ownership by a conservation-orientated NGO are regarded as the optimum tenure types for conservation management of coastal dunes.  相似文献   

Nutrient chemistry of groundwater in an intensively irrigated region of southern India   总被引：1，自引：0，他引：1  

N. Rajmohan  L. Elango 《Environmental Geology》2005,47(6):820-830

The concentration of nutrients in groundwater acts as an indicator to identify the influence of agricultural activities on the shallow subsurface environment. Hence, the present study was carried out to assess nutrient concentration (nitrate, phosphate and potassium) and understand its spatial and seasonal variations in the groundwater of Palar and Cheyyar River basin, Tamil Nadu, India. The groundwater samples collected from 43 wells were analyzed for nutrients once a month from January 1998 to June 1999. Results of the study suggested that agricultural activities, including application of fertilizers, soil mineralization processes and irrigation return flow, are major processes regulating the nutrients chemistry in the groundwater of this region. Groundwater in the sedimentary formation has comparatively higher concentration of nutrients than the groundwater in hard rock formations, which seems to be due to the adsorption of nutrients by the weathered rock materials. The seasonal water level fluctuation shows that rising water level increases nutrients concentration in groundwater due to the agriculture related activities. The results also indicate that nitrate and potassium concentrations are within the recommended drinking water limits, whereas phosphate concentration exceeds its drinking water limit and 35% of the samples are unsuitable for drinking purposes.Electronic Supplementary Material Supplementary material is available for this article at  相似文献   

地统计学方法在土壤学中的应用   总被引：24，自引：1，他引：24  

谭万能  李志安  邹碧  丁永祯 《热带地理》2005,25(4):307-311

地统计学目前在土壤科学中得到广泛的应用和发展,成为认识土壤特征的一个重要工具.地统计学的空间变异函数和克里格插值等方法是土壤性状分析的主要手段,空间变异函数主要用于描述土壤理化性状空间变异特性,不同的插值方法可优化田间试验设计和田间采样方案,克里格插值方法则特别适用于未测量点土壤属性值的估测等.近年插值方法又被广泛应用于确定区域土壤环境容量和土壤质量标准,随机模拟则用于对土壤特性进行不确定性估计等.因而,地统计学方法对我国大量土壤学资料的整合与分析具有极大的应用前景.  相似文献   

New Modes of Environmental Governance in Greater Sage-Grouse Conservation in Oregon     

Katherine Wollstein  Emily Jane Davis 《社会与自然资源》2020,33(5):555-573

Abstract

Natural resource challenges often span administrative jurisdictions and include actors and processes operating at different spatial and political scales. We applied concepts of new environmental governance to analyze Oregon’s approach to greater sage-grouse conservation. Through one in-depth case study in Lake County, we traced features of new environmental governance (cross-scale interactions, decentralization, and capacities of actors) through different governance levels. Interviews and qualitative analysis revealed that decentralization of administrative functions facilitated cross-scale interactions and relied on intermediaries, gap-filling, and perceptions of legitimacy at lower levels. State and agency guidelines steered the effort and were accompanied by financial and technical resources from multiple arenas, which increased local capacity. This study adds to the understandings of environmental governance for implementing multi-actor, multi-level conservation arrangements in resource-dependent communities. Further exploration of connections between higher levels and local contexts will reveal important, new ways to link policies with on-the-ground outcomes.  相似文献