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基于不同分辨率影像的山区耕地细碎化评价及其尺度效应 总被引：2，自引：0，他引：2
研究耕地细碎化的尺度效应对山区耕地细碎化遥感监测、耕地整治与可持续利用具有重要意义。选取贵州省坝区孙家村、丘陵区亚鱼村和山地区小坝村3个不同地貌背景的典型村为案例区,在构建细碎化测度模型基础上,量化分析0.1 m、1 m、2 m、5 m、10 m分辨率下耕地细碎化程度的尺度效应。研究结论：① 随着影像分辨率下降,不同地貌背景下的耕作地块特征有明显的尺度效应。② 不同地貌背景下的耕地细碎化程度存在差异,丘陵区的细碎化程度最高,坝区次之,山地区最低。不同影像分辨率下的耕地细碎化程度具有明显的尺度效应,3个典型村的耕地细碎化指数均呈现幂函数式下降;且不同地貌背景的耕地细碎化程度对尺度变化响应程度不同,坝区的耕地细碎化粒度响应最为强烈,丘陵区次之,山地区最弱。③ 以前1个尺度为参照计算耕地细碎化程度的损失精度时,坝区和丘陵区的耕地细碎化程度在影像分辨率由2 m变为5 m时最敏感,山地区小坝村对尺度变化的敏感度从2 m处呈现升高趋势;以基础尺度为参照时,丘陵区的耕地细碎化程度对尺度变化的敏感度最高,山地区次之,坝区最低。研究旨在为山区的耕地细碎化调查、评价以及治理提供借鉴。 相似文献
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基于土地整治模式的区域生态服务价值变化研究——以湖北省为例 总被引：1，自引：0，他引：1
运用生态服务价值理论,在湖北省平原、丘陵和山地地貌类型区中选取不同工程模式、不同建设规模的土地整治工程,开展生态服务价值评价。结果表明:地貌和建设规模均是影响生态服务价值的重要因素;对于相同地貌类型,随着土地整治建设规模的扩大,土地整治后生态服务价值相应增加;不同地貌类型下土地整治后生态服务价值增大的边际规模有所差异(平原区最大、丘陵区次之、山地区最小)。实施土地整治对区域土地生态服务价值产生一定影响,并且影响幅度随着地貌类型变化有所不同。同等建设规模下,丘陵区和山地区生态服务价值改善比平原区要显著。 相似文献
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运用广西大化县的DEM、石漠化、地质数据,通过GIS叠加分析,探讨了地质地貌因素对石漠化分布的影响.结果表明:地貌区的石漠化发生率排序为高峰丛洼地区>中峰从洼地区>峰林谷地区>丘陵山地区.发生石漠化的4种碳酸盐岩中,发生率排序为连续性灰岩>灰岩夹碎屑岩>灰岩与白云岩混合组合>灰岩与碎屑岩互层组合.碳酸盐岩含量较高的3种岩性在25°～45°坡地石漠化发生率最高,含量较低的岩性石漠化发生率高峰在35°～60°,同时发现所有岩性的石漠化发生率在3°～ 8°坡度区间存在小高峰,这与坡脚普遍的顺坡耕种有关.断层与石漠化关系密切,中度以上石漠化集中分布在断层周围1.5 km内.石漠化的发生是人为干扰、坡面侵蚀、岩石成土与溶蚀作用等综合作用的结果.在石漠化的防治中,应该综合考虑地貌发育、坡度、岩石碳酸盐含量、断层分布等多个因子的影响. 相似文献
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地球内部蕴藏着难以想象的巨大的地热能量,地热资源由于储量巨大,相对于石油、煤炭等能源,对环境的负面影响小,因此被世界各国公认为可再生清洁能源,并逐渐成为重点研究开发的新能源。地热资源虽然蕴藏丰富,但在世界各地的分布不均匀,有些国家地热资源特别丰富,全球富地热资源的国家应首届冰岛。 相似文献
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贵州省内地热资源较为丰富,在注重统一规划的基础上,对地热资源进行合理开采,有助于本地区温泉旅游业的发展。本文以贵州省为例,对贵州省内地热地质特征及地热资源开发利用情况进行了分析。 相似文献
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河南省区域地质构造位置横跨我国南北两大板块,独特的地理位置造就了河南省丰富的地质遗迹旅游资源.依据<中国国家地质公园建设技术要求与指南>,河南省地质遗迹可分为7个主类,22个亚类.就主类而言,最重要的是地质地貌景观和典型地质剖面,分别占全省地质遗迹数量的35.7%和24.3%;就亚类而言,最重要的是构造地貌、花岗岩地貌、地层剖面、温泉景观及典型矿床.依据区域构造位置与地貌类型单元,可以将河南省地质遗迹划为5个分区,不同的分区在地质遗迹资源种类、数量、级别等方面存在明显差异. 相似文献
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珠江下游较大河道总是绕开中生代晚期花岗岩的现象无论用岩性、断裂或现代地形都难以解释,而运用花岗岩原地重熔说的观点却迎刃而解,这些河道实际上是遗传河,其形成于中生代晚期花岗岩背斜（或穹窿）之间的相对低洼地带,渐新世才开始贯通,形成外流型河流,此格局没有发生大的改变而保留至今． 相似文献
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利用大量的地热流体化学成分及环境同位素（δD、δ18O、14C）测试数据，深入分析了隆起山地 构造对流型、沉降盆地传导型地热流体的化学特征及分布规律，进而对地热流体的环境同位素分 布特征及形成年龄进行了梳理总结，得出了明确的结论。结果表明：隆起山地构造对流型地热田 地热流体主要以断裂上升泉的形式出露，分布于西秦岭-祁连造山带，补给来源为当地及周边大气 降水入渗，地热流体形成年龄一般小于 5 000 ~ 30 000 a，水质较好，属“开启型”的地热系统；热储层 岩性、断裂规模及水热循环方式和深度等明显控制着地热流体化学类型、环境同位素特征和形成 年龄。沉降盆地传导型地热田地热流体主要以管井开采的方式出露；热储埋藏深度小于 1 600 m 的 地热井，地热流体补给来源为当地及周边大气降水入渗，形成年龄一般小于 5 000 ~ 30 000 a，水质
相对较好，属“半开启-半封闭型”的地热系统；热储埋藏深度介于 1 600 ~ 2 600 m 之间的地热开采 井，主要为地质历史时期逐步形成的“古水”，水化学类型复杂且水质较差，地热流体形成年龄介于
30 000 ~ 50 000 a,属“封闭型”的地热系统；热储层岩性、埋藏深度、地下水在岩层中的滞留时间与循 环深度等明显控制着地热流体化学类型、环境同位素富集程度和形成年龄。 相似文献
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Assessment of Exploration Bias in Data-Driven Predictive Models and the Estimation of Undiscovered Resources 总被引：3，自引：0，他引：3
The spatial distribution of discovered resources may not fully mimic the distribution of all such resources, discovered and
undiscovered, because the process of discovery is biased by accessibility factors (e.g., outcrops, roads, and lakes) and by
exploration criteria. In data-driven predictive models, the use of training sites (resource occurrences) biased by exploration
criteria and accessibility does not necessarily translate to a biased predictive map. However, problems occur when evidence
layers correlate with these same exploration factors. These biases then can produce a data-driven model that predicts known
occurrences well, but poorly predicts undiscovered resources.
Statistical assessment of correlation between evidence layers and map-based exploration factors is difficult because it is
difficult to quantify the “degree of exploration.” However, if such a degree-of-exploration map can be produced, the benefits
can be enormous. Not only does it become possible to assess this correlation, but it becomes possible to predict undiscovered,
instead of discovered, resources.
Using geothermal systems in Nevada, USA, as an example, a degree-of-exploration model is created, which then is resolved into
purely explored and unexplored equivalents, each occurring within coextensive study areas. A weights-of-evidence (WofE) model
is built first without regard to the degree of exploration, and then a revised WofE model is calculated for the “explored
fraction” only. Differences in the weights between the two models provide a correlation measure between the evidence and the
degree of exploration.
The data used to build the geothermal evidence layers are perceived to be independent of degree of exploration. Nevertheless,
the evidence layers correlate with exploration because exploration has preferred the same favorable areas identified by the
evidence patterns. In this circumstance, however, the weights for the “explored” WofE model minimize this bias. Using these
revised weights, posterior probability is extrapolated into unexplored areas to estimate undiscovered deposits. 相似文献
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ARDS (version 4.01), a modified version of the Arps-Roberts discovery process model, was used to forecast the remaining oil and gas resources in more than 50 provinces, super-exploration plays, and individual plays in the onshore and offshore United States for the 1995 National Oil and Gas Assessment. The size distribution of oil and gas fields was estimated for the underlying distribution of fields; the size distribution for the remaining fields was calculated to be the difference between this distribution and that of discovered fields. The guidelines that govern the 1995 National Assessment require the underlying size distribution of fields to be estimated by using only data from two standard commercial data files (the NRG Associates field file and the Petroleum Information Inc. well file). However, a variety of situations required further modification of the discovery process modeling system; for example, multiple exploration plays that occurred nearly simultaneously and also displaced each other in time, and the phenomenon of field growth introduced a large bias in the forecasts produced by the discovery process models for some provinces. 相似文献
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利用14C测年技术对驻马店市地热流体年龄进行计算,结合热储沉积时代、地热流体赋存深度可以判断流体补给来源、径流速度及可更新能力,对研究区域地热赋存规律、资源评价有重要意义。结果显示,驻马店市自西向东地热流体年龄从26ka增加到54ka,遂平县赋存深度1,400m的地热流体较上蔡县、汝南县、平舆县、新蔡县赋存深度1,000m的地热流体更为年轻,表明驻马店市地热流体以侧向缓慢径流为主,垂向交替作用极为微弱。在工程实践中,以不考虑侧向补给、垂向补给的弹性释水量作为地热流体的可开采量更为可靠。 相似文献
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浅层地温能的开发利用有助于优化区域能源结构、节约常规化石能源、减少CO2排放。为掌握兰州新区浅层地温能的适宜性特点,对该类资源的开发规划和政府决策提供科学依据,以兰州新区建成区和规划区为研究对象,在分析区内浅层地温能赋存条件的基础上,依据掌握的多年实际勘查资料和测试数据,通过综合运用改进的层次分析法、综合指数法,对兰州新区440 km2的区域进行了土壤源热泵系统适宜性评价分析。结果表明：（1） 兰州新区拥有较为优异的浅层地温能赋存条件,区内地层结构简单且分布稳定,岩土体综合热导率、比热容、地温梯度均较高,十分有利于土壤源热泵系统的应用;而受到含水层富水性弱、水质差等因素的影响,地下水源热泵系统适宜性差。（2） 基于层次分析法建立的适宜性评价模型共划分3个属性准则和7个要素指标,采用指数标度分别构建了各层次的判断矩阵,并全部高精度通过一致性检验,同时优化了各要素参数的无量纲化方法,构建的评价模型更符合实际。（3） 研究区内对于土壤源热泵适宜性影响较大的要素主要是平均热导率和地温梯度。评价显示兰州新区土壤源热泵系统适宜、较适宜区总面积359.46 km2,占评价区总面积的81.70%,主要分布于秦王川盆地平原区,其余丘陵山区地带不适宜土壤源热泵系统的建设。评价结果对兰州新区乃至其他地质条件类似地区土壤源热泵系统的开发利用规划具有指导意义。 相似文献
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The first assessment of temperature conditions in Kansas was made by geothermal gradient computations from temperature measurements in shallow boreholes, and these conditions are related to structural patterns, sedimentary cover and underlying basement properties. The area of south-central Kansas was selected for detailed study of geothermal character in relation to the geology. The aim was to quantify the relations and to determine the relationship of different variables of the temperature field. Input parameters included geothermal variables of gradient and temperature, and structure and sediment thickness. Two approaches were used: (1) the numerical computation of theoretical temperature-depth models based on conductive heat transfer, and (2) a map-comparison technique based on algebraic methods. The temperature field information usable for the map comparison is different in response to different measurements (nonequilibrium BHTs and temperatures from logged measurements in equilibrium). Derived from modelled results (plotted isotherms on cross-sections), a close relation between gradients and thermal conductivity of the sediments was confirmed. The most noticeable effect on the geothermal field, as noted quantitatively from the map-comparison study, is the relation of thickness of outcropping Permo-Pennsylvanian units because of their different thermal conductivity. The eastward increase of mean gradients is inversely related to the total sediment thickness, but this is mostly recognizable using the shallow temperature gradients. This dissimilarity gives additional evidence for a close link between gradients and thermal conductivity of the sediments in which the temperature measurements were made. The effect caused by the structure in deeper (older) units is not important and seems not to be significant, nor is the influence of the basement rock composition as indicated by the temperature modelling. 相似文献
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陡坡钼矿床是一新发现的中型钼矿床,该矿床赋存于早白垩世灵山超单元岩体与围岩的接触带内侧,矿化类型主要为细脉浸染状。矿床中金属矿物主要为黄铜矿、辉钼矿、方铅矿、闪锌矿、黄铁矿、磁铁矿、赤铁矿,次为磁黄铁矿、斑铜矿等。灵山超单元花岗岩岩石类型属高硅富碱钙碱性(偏碱性)系列,SiO2含量72～77%,K2O+Na2O总量大于7.9%,K2O/Na2O大于1。矿床的围岩蚀变叠加组合主要为硅化——钾长石化——黄铁矿化组合、硅化——绿泥石化——黄铁矿化组合。该矿床属中高温热液斑岩型钼矿床,结合岩浆岩特征,成矿作用于与岩体关系密切,并可能受幔源岩浆混合作用的影响。 相似文献
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A case study is made of the Mendeleev volcano (Kunashir Island, Southern Kuril Chain) to carry out a quantitative assessment of the influence of magmatic energy of an active volcano on the thermal regime of the soil and the ground-level air level as well as on the water balance and forest formation processes in the insular volcanic landscape. It is established that the influent channels of steam-hydrotherms cause an anomalous rise in soil temperature thereby having a substantial influence on the structure and functioning of forest ecosystems. Using a specially developed method, we calculated the geotherm-caused temperature anomalies in the soil. Calculations showed that the forest communities of the Mendeleev volcanic landscape evolved into existence and persist under the same heat and energy conditions as their zonal marginalmainland counterparts. The active volcano compensates for a deficiency in the climatic resource and ensures a stable functioning and a structural configuration of these “climatically unjustified” (extrazonal) island-arc ecosystems. We have empirically substantiated the proposition that geothermal energy of passive volcanoes serves as the factor for acceleration evolution of the insular phytobiota. This constitutes the phenomenon of biogeocenological organization of the volcanogenic landscape in the continent-to-ocean transition zone. It is shown that the magmatic geotherms of the Mendeleev volcano promoted the transgression of species and whole communities from southern areas to this boreal-forest region. We examine the rearrangement of the forest cover toward an increase in its floro- and phytocenotic diversity, the formation of relatively stable boreal-subboreal forest ecosystem with subtropical relicts as well as rudimentary buffer forest communities. It is demonstrated that a geothermal heating of the soil on the slopes and at the foot of the volcanoes of the Kuril Ridge is a large-scale (rather than an exceptional) phenomenon in the hydrothermal regime of forest ecosystems of island-arc ecoregions. 相似文献