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以清流河流域琅琊山周边815km2的区域为研究样区,通过预处理后的1∶1万DEM、1∶5万DEM、1∶25万DEM、90mSRTM3-2、30mASTERGDEM五种DEM数据和ArcGIS中内置水文模块Hydrology提取了河网和子流域等水文因子,并以1∶1万DEM提取的水文因子为基准,得到基于其余四种DEM数据的河网套合差、子流域周长差、子流域面积差,分析了四种不同源DEM数据在提取水文因子中的精度差异。实验表明,在较大尺度范围的非平原区内进行水文分析,且上游汇流面积达到0.625km2时,1∶5万DEM、90mSRTM3-2、30mASTERGDEM三种DEM提取水文因子均可获得较理想的结果。就提取水文因子的整体精度而言,其中1∶5万DEM较高,90mSRTM3-2次之,30mASTERGDEM稍差,1∶25万DEM较前三者差距较大。 相似文献
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《资源开发与市场》2016,(8)
运用空间句法,结合云南省DEM数据和美国陆地卫星影像数据,以富源县七彩胜境乡村旅游规划为例,对其土地利用、景区分布和道路结构进行分析。结果表明:1研究区坡度为0—8°的土地面积较多,其次为8°—20°的土地面积。2景区内隐形旅游资源较多,其中,海田湿地、洞上水库、回隆漏斗、天生桥等景点的影响范围大致相同,旅游价值较高;响水河水库、大洞石壁、山立哨梯地等影响范围较大。3规划区林地和耕地面积较大,其中耕地约占46.04%,林地约占19.50%;住宅用地和工业建设用地较少,合计占5.32%。4通过研究区现状和总体规划后道路结构模型可见,整合度较高的都是320国道、001、002和洞大公路段,可达性强,而景区边缘道路的整合度都相对较低。此外,总体规划后道路整合度整体较高,景区可达性和渗透性较高。 相似文献
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本文提出了水库消落区土地资源的利用问题,把水库消落区划分为常年利用区、季节性利用区和暂时性利用区.根据黄壁庄水库多年调度运行、水位变化规律,结合平山县农作物生长特性,运用频率分析计算方法,确定了3个时段(全年、3~9月、10~5月)不同保证率下的消落区土地利用高程,并估算了水库消落区土地面积和可利用土地面积,为合理利用该区土地资源,种植农作物等提供了科学依据. 相似文献
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以重庆市永川区陈食街道朱龙花等6村为例,基于全国二次调查土地利用现状图和数字高程模型(DEM),在ArcGIS 9.3平台支持下,进行了30m×30m栅格单元的土地利用与地形因子关系研究,探讨了重庆市永川土地利用特征。结果表明,海拔高度、坡度和坡向与土地利用类型的综合分析有助于从定量剖析土地利用空间分布特征;朱龙花等6村海拔、坡度及坡向均值分别为345m、17.28°和271.25°(西坡);采用高程分带、坡度分级及坡向分类的方法能直观展示土地利用格局特征。耕地(水田及旱地)主要分布在低海拔的平原和丘陵上,阳坡面积大于阴坡,水田尤为突出。园地和林地主要分布在海拔低于400m的丘陵上,坡度小于15°,西坡和西北坡分布最多;草地主要分布在海拔200—500m的平原和丘陵上,坡度小于25°,各坡向均有少量分布;水域、水利建设用地、城镇村及工矿用地分布格局类似,主要分布在300—400m的丘陵上,坡度小于6°,东坡、东南坡分布较多;其他土地分布在海拔低于500m,坡度小于25°,西坡分布较多。从土地利用与生态环境的协调发展角度看,该区域土地利用空间分布格局基本符合生态环境建设的要求,约有2.34hm2的耕地位于坡度大于25°的缓陡坡和陡坡上,应继续推行退耕还林、还草。研究结果表明,地形因子对土地利用的空间格局的影响较大;同一地形因子不同级别下的土地主导利用方式各异,土地利用类型的优势区域不尽相同。 相似文献
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玉溪市土地资源利用程度的时空变化特征 总被引:1,自引:0,他引:1
通过对2002-2005年玉溪市土地资源分类面积数据的变化分析,利用土地利用程度综合指数模型以及土地利用程度变化模型统计了各地区土地资源利用程度在时间变化、空间分布上的特征.结果表明,玉溪市土地资源利用程度总体上呈现逐年增加的时间变化趋势,表明人类活动对土地资源利用程度的影响在加剧,尤其表现在建设用地的增加和未利用地的减少上.各区域间以玉溪市中心城区红塔区的土地资源利用程度最高;其次为通海县,土地资源利用程度较小的为澄江、江川、华宁等地.土地资源利用程度较高的地区人口密度也较大,表明受自然环境条件、经济社会发展状况的影响,玉溪市土地资源利用程度具有显著的空间差异. 相似文献
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基于CA-Markov模型的新疆克州土地利用动态模拟研究 总被引:2,自引:0,他引:2
利用"3S"技术及IDRISI软件中的CA-Markov模型,以2005年为起始时刻,对新疆克州2015年土地利用格局进行模拟预测.研究认为:研究区土地利用覆盖结构呈现"两大、四小"的特点,即:草地及未利用土地面积大,而耕地、林地、水域及城乡居民工矿建设用地面积较小;与2005年相比,模拟的2015年研究区土地利用结构变化不大,仍然是以草地和未利用地面积为主,各土地利用类型面积变化也不大,其中,耕地、林地和城乡建设用地面积将略有增加,而草地、水域面积将有所减少,未利用地面积也有一定的增加,总体上,研究区内生态环境将可能进一步呈恶化趋势. 相似文献
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B. K. Panigrahi A. Das Gupta 《Journal of the American Water Resources Association》1979,15(4):1168-1172
ABSTRACT: Double-mass analysis for checking consistency of a hydrological record is considered to be essential before taking it for analysis purpose. Because of increasing computer application in hydrological analyses, in the present paper, a simple and efficient method for the double-mass checking has been developed. The problem has been formulated in FORTRAN IV language and the basic steps and a computer output of the program are presented in a flow chart and a table. 相似文献
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To improve the estimation accuracy of battery’s inner state for battery management system, an online parameters identification algorithm for Thevenin battery model is researched. The Thevenin model and parameters identification algorithm based on recursive least square adaptive filter algorithm was built with the Simulink/xPC Target. The results of hardware-in-loop experiment, which uses Federal Urban Driving Schedule test to verify the parameters identification approach, show the proposed approach can accurately identify the model parameters within 1% maximum terminal voltage estimation error, and the State of Charge error which calculated by the open circuit voltage estimates can be efficiently reduced to 4%. 相似文献
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Laurent Ahiablame Bernard Engel Indrajeet Chaubey 《Journal of the American Water Resources Association》2013,49(5):1167-1178
Pollutant coefficients have been widely used to assess runoff nonpoint source pollution from individual land uses (e.g., agricultural, residential) of a watershed. Pollutant coefficients, known as event mean concentrations (EMCs), were developed by the U.S. Environmental Protection Agency's Nationwide Urban Runoff Program (NURP) to serve as a national measure for characterizing pollutant loading in a receiving water body. The term “baseflow pollutant coefficient (BPC)” is used in this study as a surrogate for EMC to describe mean concentration of pollutants in base flow‐dominated flow. A method for characterizing base flow quantity and quality for different land uses was explored using inverse modeling with two optimization techniques (a least square method and a genetic algorithm [GA] optimization), land use information, and streamflow quantity and quality data. The inverse model was formulated as a constrained minimization problem and demonstrated with data for 15 watersheds in Indiana. Results showed that estimated pollutant coefficients are comparable to the published literature. This indicates that the proposed method has the potential to effectively estimate constituent mean concentrations for pollutant load determination in gauged and ungauged watersheds, albeit more analysis with larger and more robust datasets is desirable to further refine and validate the accuracy of the approach. 相似文献
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This paper presents a dynamic temperature model for a proton exchange membrane fuel cell (PEMFC) system. The proposed model overcomes the complexity of conventional models using first-order expressions consisting of load current and ambient temperature. The proposed model also incorporates a PEMFC cooling system, which depends upon the temperature difference between events. A dynamic algorithm is developed to detect load changing events and calculate instantaneous PEMFC temperature variations. The parameters of the model are extracted by employing the lightning search algorithm (LSA). The temperature characteristics of the NEXA 1.2 kW PEMFC system are experimentally studied to validate model performance. The results show that the proposed model output and the temperature data obtained from experiments for linear and abrupt changes in PEMFC load current are in agreement. The root-mean-square error between the model output and experimental results is less than 0.9. Moreover, the proposed model outperforms the conventional models and provides advantages such as simplicity and adaptability for low and high sampling data rates of input variables, namely, load current and ambient temperature. The model is not only helpful for simulations but also suitable for dynamic real-time controllers and emulators. 相似文献
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A. U. Mallik 《Environmental management》1995,19(5):675-684
Fire and logging in nutrient-poor temperate forests with certain ericaceous understory plants may convert the forests into
heaths. The process of disturbance-induced heath formation is documented by using examples ofCalluna in western Europe,Kalmia in Newfoundland, andGaultheria (salal) in coastal British Columbia. In a cool, temperate climate, rapid vegetative growth ofCalluna, Kalmia, and salal following disturbance results in increasing organic accumulation (paludification), nutrient sequestration, soil
acidification, and allelochemicals. These are thought to be the main reasons to conifer regeneration failure in disturbed
habitats.
If continuation in forest is a land-use objective, then temperate forests with an ericaceous understory should not be logged
unless effective silvicultural methods are devised to control the ericaceous plants and restore forest regeneration. Preharvest
vegetation control may be considered as an option. Failure to control the understory plants may lead to a long-term vegetation
shift, from forest to heathland, particularly in nutrient-poor sites. Successful methods of controllingKalmia andGaultheria, however, have yet to be developed. While theKalmia- andGaultheria- dominated heathlands are undesirable in Canada and the Pacific Northwest, a wide range ofCalluna heathlands of western Europe are being conserved as natural and seminatural vegetation. 相似文献
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Donald L. Chery Calvin G. Clyde Roger E. Smith 《Journal of the American Water Resources Association》1979,15(4):1126-1145
ABSTRACT: Mathematical models for predicting watershed surface flow responses are available, most of which are elaborate nonlinear numerical surface and channel flow models linked with infiltration models. Such models may be used to make predictions for ungaged areas, assuming an acceptable fitting of the model to the topography and roughness of the real system. For some application purposes, these models are impractical because of their complexity and expensive computer solutions. A procedure is developed that uses a complex model of an ungaged area to derive a simpler parametric nonlinear system model for repetitious simulation with input sequences. The predicted flow outputs are obtained with the simpler model at significant savings of money and time. The procedures for constructing a complex kinematic model of a 40 acre (161,880 m2) reference watershed and deriving the simpler system model are outlined. The results of predictions from both models are compared with a selected set of measured events, all having essentially the same initial conditions. Peak discharges ranged from 3 to 118 ft3/sec (0.085 to 3.34 m3/sec), which includes the largest event of record. The inherent limitations of lumped systems models are demonstrated, including the bias caused by their inability to model infiltration losses after rainfall ceases. Computer costs and times for the models were compared. The derived simple model has a cost advantage when repeated use of a model is required. Such an applications hydrologic model has an engineering tradeoff of reduced accuracy, and lumping bias, but is more economical for certain design purposes. 相似文献