首波震相跟踪系统     

邵平荣  洪星 《福建地震》2006,(Z2)

本文简述了首波震相跟踪系统的主要功能和技术。  相似文献   

航空摄影区域可视化软件的设计与实现     

张杰  王红卫等 《测绘学院学报》2002,19(4):280-282

介绍了航空摄影区域可视化的设计与实现过程，解决了摄影区域内航片预览、航线划分及有关信息查询等软件的实际问题。实现过程采用了高级软件编程平台VC 6.0及可视化技术，经实用测试达到了设计目标。文中重点陈述了软件的实现步骤、关键技术及特殊情况的解决方案。  相似文献   

Windows下二维气象绘图软件——客观分析诊断图形系统   总被引：14，自引：3，他引：14  

郑永光  王洪庆  陶祖钰  陈敏 《气象》2002,28(3):42-45

客观分析诊断图形系统是一款操作界面友好的二维气象绘图软件，它运行于微软Windows操作系统下，具有多种数据接口，能够绘制等值线、流线、矢量、多种投影地图及不规则数据分布图等多种图形。客观分析诊断图形系统还能够对气象地面、探空数据进行客观分析诊断，并能根据用户所选择气压层、变量由客观分析诊断的结果绘制相应图形。  相似文献   

浅谈GPS测量多路径误差   总被引：2，自引：1，他引：1  

谭观龙 《地理空间信息》2008,6(5):56-58

对GPS测量多路径误差进行了分析,根据多路径误差变化同时间段一致性特性,采用残差相减重复部分的方法,探索抑制多路径效应的途径。  相似文献   

Mapping Paleo‐Fire Boundaries from Binary Point Data: Comparing Interpolation Methods     

Amy Hessl  Jennifer Miller  James Kernan  David Keenum  Don McKenzie 《The Professional geographer》2007,59(1):87-104

Fire history studies have traditionally emphasized temporal rather than spatial properties of paleo‐fire regimes. In this study we compare four methods of mapping paleo‐fires in central Washington from binary point data: indicator kriging, inverse distance weighting, Thiessen polygons, and an expert approach. We evaluate the results of each mapping method using a test (validation) dataset and receiver operating characteristic plots. Interpolation methods perform well, but results vary with fire size and spatial pattern of points. Though all methods involve some subjectivity, automated interpolation methods perform well, are replicable, and can be applied across varying landscapes.  相似文献   

土壤侵蚀预报研究中的标准小区问题论证   总被引：19，自引：2，他引：17  

张科利  刘宝元  蔡永明 《地理研究》2000,19(3):297-302

确定标准小区在土壤侵蚀预报中具有重要意义,也是进行土壤侵蚀规律研究的必要基础。文中根据我国的自然环境条件、土壤侵蚀特征、农业生产特点,通过分析土壤侵蚀发生的地形特点、已有资料的坡度变化范围,以及土壤流失量估算中的误差变化规律,提出并论证了我国土壤侵蚀研究中的标准小区应选定15°坡度、20m坡长、5m宽的清耕休闲地。小区每年按传统方法准备成苗床,并按当地农作习惯适时中耕,保证没有明显的杂草生长。  相似文献   

Are spatial patterns of soil moisture at plot scales generalisable across catchments,climates, and other characteristics? A synthesis of synoptic soil moisture across the Mid-Atlantic     

Charles I. Scaife  Jonathan M. Duncan  Laurence Lin  Christina Tague  Colin D. Bell  Lawrence Band 《水文研究》2021,35(9):e14313

The spatial variation of soil moisture over very small areas (<100 m²) can have nonlinear impacts on cycling and flux rates resulting in bias if it is not considered, but measuring this variation is difficult over extensive temporal and spatial scales. Most studies examining spatial variation of soil moisture were conducted at hillslope (0.01 km²) to multi-catchment spatial scales (1000 km²). They found the greatest variation at mid wetness levels and the smallest variation at wet and dry wetness levels forming a concave down relationship. There is growing evidence that concave down relationships formed between spatial variation of soil moisture and average soil moisture are consistent across spatial scales spanning several orders of magnitude, but more research is needed at very small, plot scales (<100 m²). The goal of this study was to characterise spatial variation in shallow soil moisture at the plot scale by relating the mean of measurements collected in a plot to the standard deviation (SD). We combined data from a previous study with thousands of new soil moisture measurements from 212 plots in eight catchments distributed across the US Mid-Atlantic Region to (1) test for a generalisable mean–SD relationship at plot scales, (2) characterise how landcover, land use, season, and hillslope position contribute to differences in mean–SD relationships, and (3) use these generalised mean–SD relationships to quantify their impacts on catchment scale nitrification and denitrification potential. Our study found that 98% of all measurements formed a generalised mean–SD relationship like those observed at hillslope and catchment spatial scales. The remaining 2% of data comprised a mean–SD relationship with greater spatial variation that originated from two riparian plots reported in a previous study. Incorporating the generalised mean–SD relationship into estimates of nitrification and denitrification potential revealed strong bias that was even greater when incorporating mean–SD observations from the two riparian plots with significantly greater spatial variation.  相似文献   

Supporting USLE‐MM reliability by analyzing soil loss measurement errors          下载免费PDF全文

Vincenzo Bagarello  Vito Ferro 《水文研究》2017,31(4):847-853

Sampling the collected suspension in a storage tank is a common procedure to obtain soil loss data. A calibration curve of the tank has to be used to obtain actual concentration values from those measured by sampling. However, literature suggests that using a tank calibration curve was not a common procedure in the past. For the clay soil of the Sparacia (Italy) experimental station, this investigation aimed to establish a link between the relative performances of the USLE‐M and USLE‐MM models, usable to predict plot soil loss at the event temporal scale, and soil loss measurement errors. Using all available soil loss data, lower soil loss prediction errors were obtained with the USLE‐MM (exponent of the erosivity term, b₁ > 1) than the USLE‐M (b₁ = 1). A systematic error of the soil loss data is unexpected for the Sparacia soil because the calibration curve does not depend on the water level in the tank. In any case, this type of error does not have any effect on the b₁ exponent. Instead, this exponent decreases as the level of underestimation increases for increasing soil loss values. This type of error can occur at Sparacia if it is assumed that a soil loss measurement can be obtained by a bottle sampler dipped close to the bottom of the tank after mixing the suspension and assuming that the measured concentration coincides with the actual one. In this case, the risk is to obtain a lower b₁ value than the actual one. In conclusion, additional investigations on the factors determining errors in soil loss data collected by a sampling procedure are advisable because these errors can have a noticeable effect on the calibrated empirical models for soil loss prediction.  相似文献   

全站仪在森林生态系统大样地定位中的应用     

林观土  王长委  韩锡君  徐庆华  陈军 《测绘科学》2011,36(4):242-243,207

本文介绍全站仪在森林大样地内进行放样测量、树高测量及胸径测量的原理与方法,通过误差传播定律分析其测量的精度,结果表明:全站仪在森林生态调查定位中是可行的.放样距控制点300m的方格顶点的精度可达到1/100,树高测量的精度可达到1/250,胸径测量的精度可达到1/50,可满足林业调查规范的要求.对于日后森林生态系统大样...  相似文献   

Applying the box plot to the recognition of footwall alteration zones related to VMS deposits in a high-grade metamorphic terrain, South Africa, a lithogeochemical exploration application     

H.F.J. Theart  R. Ghavami-Riabi  H. Mouri  P. Gräser 《Chemie der Erde / Geochemistry》2011,(2):143-154

Alteration zones (more commonly foot wall alteration zones) are related to volcanic-hosted massive sulfide (VMS) deposits and represent unique features that may be targeted during exploration. Of these, the chloritic foot wall alteration pipe is the most extensive and characteristic of VMS deposits. This feature is geochemically identified by a strong relative enrichment in aluminium and magnesium and a coupled depletion in calcium and sodium, giving rise to chloritic rocks in the primary environment of formation. During high grade regional metamorphism such chloritic precursor rock types are replaced by an unusual mineral paragenesis, typically containing magnesium rich cordierite, phlogopite, orthoamphiboles or orthopyroxenes and aluminium rich minerals such as sillimanite and corundum. This suggests that the unusual geochemical features of the alteration zone, retained during the deformation and metamorphism, should be recognisable in lithogeochemical exploration.The massive sulfide deposit in the eastern part of the metamorphic Namaqua Province, South Africa, at Areachap, Kantienpan and the defunct Prieska Cu–Zn Mine are hosted by a Mid-Proterozoic volcano sedimentary succession known as the Areachap Group. These deposits were affected by a complex deformation and metamorphic history and represent examples of upper amphibolite to granulite grade metamorphosed VMS deposits.The application of the known lithogeochemical methods is especially complicated where the geology is not well understood, due to the poor rock exposure of complexly deformed and metamorphosed areas, such as in the eastern part of the Namaqua Province.The box plot presents a more readily applicable lithogeochemical method to characterize and identify the alteration process, but it was designed for relatively un-metamorphosed environments. It is demonstrated here that the box plot may also be applied to high-grade metamorphic terrains and that the mineral phases used in defining the boxplot in low grade metamorphic environments may be replaced by their equivalents in high grade metamorphic terrains. The compositional trends of the metamorphic minerals themselves may be used in defining the boxplot for high grade metamorphic terrains. These include the transition of: annite to phlogopite; grossular to almandine or pyrope, augite to enstatite or clinoenstatite, and hornblende to gedrite or cummingtonite. Close to the ore zone, the relative Mg content of pyroxene, cordierite and biotite are higher than further away from this zone. It could be demonstrated that the changes in the mineral compositions are gradational when comparing unaffected rocks with progressively more altered wall rocks.Conclusions based on an application of the isocon method demonstrate that primary footwall alteration zones in the Areachap Group's VMS deposits are characterized by elemental depletion of Na₂O, CaO, Sr, Ni, V and La and enrichment of MgO, Fe₂O_3(total), S, Zn, SiO₂, Co and F. It is shown that the whole rock compositions of rocks that were independently identified as the metamorphic equivalents of altered rocks, using the isocon method, plot in the correct place in the box plot for high grade regionally metamorphosed terrains. This establishes the box plot as an effective and practical tool for lithogeochemical exploration for VMS deposits in complexly deformed high grade metamorphosed terrains.  相似文献