基于水资源生态足迹的浑河流域水资源利用评价          下载免费PDF全文

王秀颖  刘和平 《水文》2016,36(3):50-55

用水资源生态足迹模型计算浑河流域2005~2013年水资源生态足迹和水资源生态承载力,并基于各评价指标对浑河流域水资源利用情况进行评价。结果表明:2005~2013年浑河流域水资源生态足迹呈现不显著的下降趋势,水资源生态承载力呈现波动变化;流域一直处于水资源生态赤字状态,仅在2010年出现盈余;流域水资源生态足迹指数低于可持续发展足迹指数范围,但万元GDP水资源生态足迹持续下降。总体来看,流域水资源利用处于不可持续状态,但2010年后流域水资源利用效率明显提高,并向着可持续的方向发展。  相似文献   

Temperature dependence of variations in the end of the growing season from 1982 to 2012 on the Qinghai–Tibetan Plateau     

Mingjun Ding  Qian Chen  Lanhui Li  Zhaofeng Wang  Linshan Liu 《地理信息系统科学与遥感》2016,53(2):147-163

A growing number of studies have focused on variations in vegetation phenology and their correlations with climatic factors. However, there has been little research on changes in spatial heterogeneity with respect to the end of the growing season (EGS) and on responses to climate change for alpine vegetation on the Qinghai–Tibetan Plateau (QTP). In this study, the satellite-derived normalized difference vegetation index (NDVI) and the meteorological record from 1982 to 2012 were used to characterize the spatial pattern of variations in the EGS and their relationship to temperature and precipitation on the QTP. Over the entire study period, the EGS displayed no statistically significant trend; however, there was a strong spatial heterogeneity throughout the plateau. Those areas showing a delaying trend in the EGS were mainly distributed in the eastern part of the plateau, whereas those showing an advancing trend were mostly scattered throughout the western part. Our results also showed that change in the vegetation EGS was more closely correlated with air temperature than with precipitation. Nonetheless, the temperature sensitivity of the vegetation EGS became lower as aridity increased, suggesting that precipitation is an important regulator of the response of the vegetation EGS to climate warming. These results indicate spatial differences in key environmental influences on the vegetation EGS that must be taken into account in current phenological models, which are largely driven by temperature.  相似文献   

Stochastic modeling based on deterministic formulation: An example   总被引：1，自引：0，他引：1  

G. R. Dargahi-Noubary 《Mathematical Geology》1992,24(2):161-169

In the context of seismology, an example of stochastic modeling on the basis of an established deterministic formulation is presented. The advantages of this approach to modeling over those based solely on statistical fit are discussed. It is demonstrated that the result of applying this procedure is a model whose main parameter has a physical interpretation, and therefore a validation based on criteria other than statistical goodness of fit is also possible. Statistical inference together with some demonstrating examples are also included.  相似文献   

钾长石矿物在全新世样品光释光测年中的应用与校正问题   总被引：9，自引：9，他引：0       下载免费PDF全文

李国强  赵晖  文星  彭海梅  陈发虎 《第四纪研究》2010,30(1):54-61

使用钾长石进行释光测年时,由于长石的释光信号存在异常衰减,会导致沉积事件年龄的低估。对中国北方4个全新世样品分别使用石英和钾长石矿物组分释光测年,通过测量钾长石的衰退系数(g值)对钾长石使用再生剂量法获得的表征年龄进行了校正。发现对于本文所研究的年轻样品钾长石表征年龄与石英年龄相比系统偏小约2％～9％,钾长石校正年龄与石英年龄相比则严重偏大约16％～40％,表明使用g值无法校正年轻样品的钾长石年龄。对于年轻样品,钾长石IRSL信号异常衰减现象对测年结果的影响是可以忽略的。  相似文献   

Determination of Fluorine and Chlorine by Pyrohydrolysis and Ion Chromatography: Comparison with Alkaline Fusion Digestion and Ion Chromatography     

Qiaoyun Wang  Akio Makishima  Eizo Nakamura 《Geostandards and Geoanalytical Research》2010,34(2):175-183

A method to determine F and Cl in silicate materials by employing pyrohydrolysis and ion chromatography (IC) is described. Pyrohydrolysis involved mixing a pulverised sample (∼ 40 mg) with V₂O₅ (∼ 160 mg) and heating to 1100 °C under a wet oxygen flow in a quartz tube. Recovery yields of F and Cl were ∼ 97% using a NaF + NaCl standard solution. Detection limits of the pyrohydrolysis-IC method for silicate samples were 0.36 and 0.69 μg g^-1 for F and Cl, respectively. Fluorine and Cl concentrations were determined in the reference materials JB-2, JB-3 and JA-1 from the GSJ; BCR-2, BHVO-1, BHVO-2, AGV-1 and AGV-2 from the USGS; and NIST SRM 610, 612 and 614 glasses. Precisions (RSD) for determinations of F were 1–13% (except NIST SRM 614) and 2–19% for Cl, and were dependent on the concentration and blank correction. Most results obtained in this study were in good agreement with those of previous studies. In comparison, the Na₂CO₃ + ZnO fusion method at 900 °C showed that the yields of F and Cl by alkaline fusion systematically decreased with fusion duration time. The yields were 84% and 83% for JB-3, inferring that F and Cl were lost in this alkaline fusion.  相似文献   

柴里煤矿二水平岩巷的工程地质问题探讨     

王四洋  钱勋等 《中国煤田地质》2001,13(3):45-47,49

论证了柴里矿区现代地应力场为大地静力场型，指出地应力研究的工程意义，通过层位，实践，经济效益几方面的对比，指出三灰是二水平主干岩层位选择的最佳层位。  相似文献   

裂隙、离层及冒落带的声波成像识别方法   总被引：9，自引：0，他引：9  

韩绪山  张景考等 《中国煤田地质》2001,13(3):65-66

煤层采空形成的冒落带，裂隙带和沉降变形情况的查明对灾害防治及土地利用是非常重要的，在勘察钻孔中进行声波扫描成像测井能提供清晰直观的图像资料，给工程地质的评价分析提供了可靠的依据。  相似文献   

Recognition of the hydrogeological potential using electrical sounding in the Khemisset-Tiflet region,Morocco          下载免费PDF全文

Fatima Zahra FAQIHI  Anasse BENSLIMANE  Abderrahim LAHRACH  Mohamed CHIBOUT  Mohamed EL MOKHTAR 《地下水科学与工程》2020,8(2):172-179

The low recharge of reservoirs and the increasing demand for water limit the potential of mobilized resources, especially in arid to semi-arid areas like Morocco. Integrated management is essential to safeguard this resource. In respect with this perspective, this work provides the analysis of hydrogeological potential of Khemisset-Tiflet region, which falls within the action area of the Sebou Hydraulic Basin Agency. The basis of our studies was as follows:(1) The interpretation of the existing geoelectric data;(2) application of geophysical methods for non-destructive reconnaissance and their integration into a Geographic Information System(GIS). The analysis demonstrates that: The map of the isohypses and the geoelectric cross-section of the substratum of the superficial roof aquifer show clearly a plunge associated with development of the Paleozoic roof in the South and the direction of flow of the surface water is from south to north, from the upper zone to the north of the El Kansera dam. These conclusions constitute very useful contribution for any resource management projects in this area.  相似文献   

Static compression of α-Fe<Subscript>2</Subscript>O<Subscript>3</Subscript>: linear incompressibility of lattice parameters and high-pressure transformations     

H.?Liu  W. A.?Caldwell  L. R.?Benedetti  W.?Panero  R.?JeanlozEmail author 《Physics and Chemistry of Minerals》2003,30(9):582-588

The high-pressure behavior of -Fe₂O₃ has been studied under static compression up to 60 GPa, using a laser-heated diamond anvil cell. Synchrotron-based angular-dispersive X-ray diffraction shows that the sample remains in the corundum structure up to 50 GPa, but with the appearance of coexisting diffraction lines from a high-pressure phase at pressures above 45 GPa. A least-squares fit of low-pressure phase data to an Eulerian finite-strain equation of state yields linear incompressibilities of K _{a 0}=749.5 (± 18.4) GPa and K _{c 0}= 455.7 (± 21.4) GPa, differing by a factor of 1.6 along the two directions. The enhanced compressibility of the c axis may lead to breaking of vertex- or edge-sharing bonds between octahedra, inducing the high-pressure phase transformation at 50 GPa. Analysis of linear compressibilities suggests that the high-pressure phase above 50 GPa is of the Rh₂O₃ (II) structure. Continuous laser heating reveals a new structural phase transformation of -Fe₂O₃ at 22 GPa, to an orthorhombic structure with a=7.305(3) Å, b=7.850(3) Å, and c=12.877(14) Å, different from the Rh₂O₃ (II) structure.  相似文献   

近四十年来山东南四湖环境演化的元素地球化学记录   总被引：17，自引：5，他引：17  

杨丽原  沈吉  张祖陆  朱育新  孙庆义 《地球化学》2003,32(5):453-460

根据^137Cs放射性同位素比率获得了南四湖上级湖沉积岩芯(0～20cm)分辨率达1．4年过去约43年的连续沉积序列(1957～2000年)。利用ICP-AEs和HG-AFS获得了柱状沉积物中的主要元素含量。根据聚类分析和沉积原理与人类活动进程的对比，认为Cu、V、K、Ni、Be、Cr、Ti、Ba、Mg、Al、Fe、zn、Na、Co、Ca和Sr等元素的含量变化主要受流域侵蚀物质的变化控制；Hg、Pb、As和Mn则主要来源于人为污染。受流域侵蚀物质来源控制的元素含量变化可以分为两个阶段：1957～1962年为上升阶段，1962～2000年为下降阶段，这与区域气候向干旱化方向渐变和历史记载资料一致。人为污染来源的元素如Hg、Pb和Mn在1982年后表现为明显上升趋势，这与该地区以燃煤为主的能源结构且华东地区为最重要的煤田能源基地、城市扩展及区域经济发展有密切关系；而As含量在1974～1982年间增加明显，这与该流域内当时农业上大量使用含As农药，残留物随农业退水进入湖泊水体有关；尔后含As农药使用量减少，沉积物中的As含量明显下降。  相似文献