粗差发现和定位能力与相关系数的关系   总被引：2，自引：0，他引：2  

顾利亚  岑敏仪  李志林 《武汉大学学报(信息科学版)》2005,30(7):621-624

根据粗差判断方程中的判断矩阵和两个统计检验量之间相关系数的函数式,论证了两种不同的研究方法所确定的粗差不能定位的数学模型实际上是相等的。通过算例,不仅说明两种研究方法对观测量不能定位粗差的判断是一致的,而且使用判断矩阵研究观测量的粗差发现和定位能力会更加方便简单。  相似文献   

FY-1C可见光通道衰减分析及订正试验          下载免费PDF全文

谷松岩 邱红刘玉洁  范天锡 《应用气象学报》2002,13(6):734-740

利用FY-1C连续两年的遥感资料，以敦煌辐射校正场为分析区，系统分析了FY-1C可见光、近红外通道的衰减特征，开展了通道衰减订正试验。分析结果表明，FY-1C除可见光通道1衰减强烈外，其它各可见光、近红外通道衰减性能稳定。利用统计分析法，可以建立定标系数衰减订正量随时间的变化关系。订正后的定标系数与2000年辐射校正场外定标实验结果一致性很好。更新后的定标系数可以有效克服通道衰减带来的通道反射率测值误差，提高FY-1C可见光、近红外通道遥感资料定量应用的精度。  相似文献   

Groundwater-flow modeling in the Yucatan karstic aquifer, Mexico   总被引：1，自引：0，他引：1  

Roger González-Herrera  Ismael Sánchez-y-Pinto  José Gamboa-Vargas 《Hydrogeology Journal》2002,10(5):539-552

The current conceptual model of the unconfined karstic aquifer in the Yucatan Peninsula, Mexico, is that a fresh-water lens floats above denser saline water that penetrates more than 40 km inland. The transmissivity of the aquifer is very high so the hydraulic gradient is very low, ranging from 7–10 mm/km through most of the northern part of the peninsula. The computer modeling program AQUIFER was used to investigate the regional groundwater flow in the aquifer. The karstified zone was modeled using the assumption that it acts hydraulically similar to a granular, porous medium. As part of the calibration, the following hypotheses were tested: (1) karstic features play an important role in the groundwater-flow system; (2) a ring or belt of sinkholes in the area is a manifestation of a zone of high transmissivity that facilitates the channeling of groundwater toward the Gulf of Mexico; and (3) the geologic features in the southern part of Yucatan influence the groundwater-flow system. The model shows that the Sierrita de Ticul fault, in the southwestern part of the study area, acts as a flow barrier and head values decline toward the northeast. The modeling also shows that the regional flow-system dynamics have not been altered despite the large number of pumping wells because the volume of water pumped is small compared with the volume of recharge, and the well-developed karst system of the region has a very high hydraulic conductivity. Electronic Publication  相似文献   

Hydrothermal Redistribution of Rare—Earth Elements in Pingxiang Dacite,Guangxi     

顾尚义  万国江  毛健全  张启厚 《中国地球化学学报》2002,21(2):170-174

Distribution of the rare-earth elements (REE) in dacite has been studied so as to get a better understanding of the migration behavior of REE during alteration. Both unaltered and altered samples were collected in an unpolluted area of Guangxi Zhuang Autonomous Region, southwest China. The REE concentrations were analyzed by ICP-MS. It is concluded that the REE were enriched during dacite alteration in varying degrees. The chondrite-normalized REE patterns of altered samples approximately maintain the characteristics of unaltered samples. However, if we normalize the REE concentrations of altered samples with unaltered dacite, fractionation of REE will appear. The LREE are more enriched than HREE in all altered samples with the LREE possibly precipitated as carbonate minerals. Both positive and negative Eu anomalies exist. Enrichment, immobility and depletion are noticed for the element Lu. Heavy mineral alteration, difference in stability constant between carbonate LREE and HREE complexes, downward migration of weathering fluid and microenvironment change may be responsible for the fractionation of REE in the altered dacite.  相似文献   

The base of the Portsdown Chalk Formation (Chalk Group, White Chalk Subgroup) in the BGS Big Almer Wood Borehole, Dorset, southern England     

C. Roger BristowIan Wilkinson  Chris WoodMark Woods 《Proceedings of the Geologists' Association. Geologists' Association》2002,113(1):37-45

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辽宁省数字化地震前兆数据库的建立     

魏柳  谷光裕 《东北地震研究》2002,18(2):74-77

地震前兆数据一直是地震分析预报必不可少的重要数据资源。随着辽宁省地震前兆台站数字化技术改造的开展，地震前兆模拟记录将逐步被数字化记录所取代。我们结合数字化技术改造的实际情况，采用先进的网络关系数据库模型构造了辽宁省数字地震前兆数据库。该数据库直接面向整个地震系统，为地震预报提供详实的数据服务和先进的研究手段。本文对数据库系统、数据库总体设计及数据共享服务也进行了深入研究和讨论。  相似文献   

A 1500-year record of climatic and environmental change in ElkLake, Minnesota I: Varve thickness and gray-scale density     

Walter Dean  Roger Anderson  J. Platt Bradbury  David Anderson 《Journal of Paleolimnology》2002,27(3):287-299

The deepest part (29.5 m) of Elk Lake, ClearwaterCounty, northwestern Minnesota, contains a complete Holocene section that iscontinuously varved. The varve components are predominantly autochthonous(CaCO₃, organic matter, biogenic silica, and several iron andmanganese minerals), but the varves do contain a minor detrital-clastic(aluminosilicate) component that is predominantly wind-borne (eolian) andprovides an important record of atmospheric conditions. Singular spectrumanalysis (SSA) and wavelet analysis of varve thickness recognized significantperiodicities in the multicentennial and multidecadal bands that varied inpower (i.e., variable significance) and position (i.e., variable period) withinthe periodic bands. Persistent periodicities of about 10, 22, 40, and 90 years,and, in particular, multicentennial periodicities in varve thickness and otherproxy variables are similar to those in spectra of radiocarbon production, aproxy for past solar activity. This suggests that there may be a solar control,perhaps through geomagnetic effects on atmospheric circulation. Multicentennialand multidecadal periodicities also occur in wavelet spectra of relativegray-scale density. However, gray-scale density does not appear to correlatewith any of the measured proxy variables, and at this point we do not know whatcontrolled gray scale.  相似文献   

The interpretation of reaction textures in Fe‐rich metapelitic granulites of the Musgrave Block,central Australia: constraints from mineral equilibria calculations in the system K2O–FeO–MgO–Al2O3–SiO2–H2O–TiO2–Fe2O3     

R. W. White  Roger Powell  G. L. Clarke 《Journal of Metamorphic Geology》2002,20(1):41-55

Fe‐rich metapelitic granulites of the Musgrave Block, central Australia, contain several symplectic and coronal reaction textures that post‐date a peak S2 metamorphic assemblage involving garnet, sillimanite, spinel, ilmenite, K‐feldspar and quartz. The earliest reaction textures involve spinel‐ and quartz‐bearing symplectites that enclose garnet and to a lesser extent sillimanite. The symplectic spinel and quartz are in places separated by later garnet and/or sillimanite coronas. The metamorphic effects of a later, D3, event are restricted to zones of moderate to high strain where a metamorphic assemblage of garnet, sillimanite, K‐feldspar, magnetite, ilmenite, quartz and biotite is preserved. Quantitative mineral equilibria calculations in the system K₂O–FeO–MgO–Al₂O₃–SiO₂–H₂O–TiO₂–Fe₂O₃ (KFMASHTO) using Thermocalc 3.0 and the accompanying internally consistent dataset provide important constraints on the influence of TiO₂ and Fe₂O₃ on biotite‐bearing and spinel‐bearing equilibria, respectively. Biotite‐bearing equilibria are shifted to higher temperatures and spinel‐bearing equilibria to higher pressures and lower temperatures in comparison to the equivalent equilibria in K₂O–FeO–MgO–Al₂O₃–SiO₂–H₂O (KFMASH). The sequence of reaction textures involving spinel is consistent with a D2 P–T path that involved a small amount of decompression followed predominantly by cooling within a single mineral assemblage stability field. Thus, the reaction textures reflect changes in modal proportions within an equilibrium assemblage rather than the crossing of a univariant reaction. The D3 metamorphic assemblage is consistent with lower temperatures than those inferred for D2.  相似文献   

A high-resolution magnetotelluric survey of the Iapetus Suture Zone in southwest Scotland   总被引：1，自引：0，他引：1  

Sebastian Tauber  Roger Banks  Oliver Ritter  Ute Weckmann 《Geophysical Journal International》2003,153(3):548-568

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美国国家公园的地理信息系统(GIS)   总被引：16，自引：0，他引：16  

辜寄蓉  范晓 《四川地质学报》2003,23(1):41-44

通过介绍美国国家公园中GIS的管理与实施经验，结合我国在地质公园的GIS应用情况，达到促进我国国家地质公园及其它国家公园中的GIS应用的目的。  相似文献