两城水源地喀斯特水资源评价     

王延恩  李念国  韩汝钊 《地下水》2003,25(2):103-105

两城水源地具有较丰富的喀斯特水，根据长期观测资料，充分考虑水资源的各种补给和开采条件，应用水均衡原理，对其水资源量进行定量评价，获得允许可开采量，为工农业供水提供可靠依据。  相似文献   

Compositional Geometry and Mass Conservation   总被引：1，自引：0，他引：1  

Robert F. Shurtz 《Mathematical Geology》2003,35(8):927-937

A geometrical structure is imposed on compositional data by physical and chemical laws, principally mass conservation. Therefore, statistical or mathematical investigation of possible relations between data values and such laws must be consistent with this structure. This demands that geometrical concepts, such as points that specify both mass and composition in linear space, and lines in projective space that specify composition only, be clearly defined and consistent with mass conservation. Mass thus becomes the norm in composition space in place of the Euclidean norm of ordinary space. Coordinate transformations inconsistent with this geometry are accordingly unnatural and misleading. They are also unnecessary because correlation arising from the constant mass presents no unusual difficulty in the analysis of the underlying quadratic form.  相似文献   

Use of accessory zircon for the quantification of volume changes in ductile shear zones cutting plutonic rocks     

Robert Sturm  Hans Peter Steyrer 《Chemie der Erde / Geochemistry》2003,63(1):31-54

  相似文献   

地震灾害现场救援搜索策略与搜索方法有关问题的讨论   总被引：13，自引：3，他引：13  

顾建华  陈维锋  郝清源 《国际地震动态》2003,(6):6-12

对地震灾害现场的搜索策略和搜索方法等有关问题进行了讨论，推荐了常用的搜索策略，对不同搜索方法的利弊进行了分析；对搜索方法的使用也做了讨论。通过讨论，文章就搜索分队的组成、任务、装备和部署等提出了建议。  相似文献   

陆面过程模式的改进及其检验   总被引：11，自引：0，他引：11  

周锁铨  代刊  陈涛  屠其璞  陈万隆 《气象学报》2003,61(3):275-290

文中对陆面过程模式 (BATS)进行了改进 ,改进后的模式能较好地模拟地表物理量的年、季和日变化 ,它有两方面的特点 :采用热扩散方程模拟 7层土壤温度 ,模拟的温度可与实测值进行比较 ;在BATS的地表径流方案中 ,考虑了空间不均匀性的一般地表径流 (GVIC)过程 ,研究结果表明 :⑴模式能很好地模拟各层土壤温度的年、季和日变化。冬季土壤温度下层高于上层 ,而在夏季上层高于下层 ,这种上下层温度的转换时间大约在 4和 10月份 ,这与实测土壤温度的年变化非常一致。较为准确地模拟了各层土壤温度日变化的时滞效应。⑵用南京和武汉站的资料 ,将BATS地表径流方案模拟的地表水分分量与GVIC方案进行比较 ,BATS地表径流方案模拟的地表水分分量 ,与总水量的平衡相差较大 ,而GVIC模拟的效果相对较好 ,地表总水量基本上与降水总量达到了平衡  相似文献   

Quantitative Evaluation of Water Deposited By Dew on Monuments   总被引：1，自引：0，他引：1  

Dario Camuffo  Roberta Giorio 《Boundary-Layer Meteorology》2003,107(3):655-672

Samples of White and Green Carrara marble, and three types oflimestone and brick exposed in the field vertically and horizontally were used to evaluate condensationon monuments during clear sky nights. Experiments in a simulation chamber under controlledconditions led to a general equation for the actual amount of water deposited on a surface by dew.This is determined by: How much and for how long the surface temperature falls below the dew point,the moisture content in the air and the ventilation. On clear nights, the condensation on buildingstructures facing the sky may reach some 0.2 kg m^-2 (or 0.2 mm), whereas condensation on verticalsurfaces is very small. Computation of the seasonal trend of night-time condensationshowed that the maximum amount of water condensed per night occurs in the autumn, with the moreabundant concentration of moisture in the air. The total amount of water condensed per month isfound to be a maximum in the summer-autumn period. Morning condensationfor the thermal inertia of monuments is also relevant, and has been calculated to reach the same order of magnitude as thenocturnal dew. A detailed analysis of the temperature and mixing ratio profiles near a condensingsurface has shown two different situations. In still air, the two profiles follow an exponentiallaw and the thermal and the concentration layers lie within a few tens of millimetres. Inthe presence of turbulence, the thickness of these two layers is dramatically reduced. In still air, infront of a vertical, chilly surface, the deposition rate of air pollutants by thermophoresis and/orStefan flow is increased by 3 or 4 times in comparison with a horizontal surface. In the presence ofturbulence, the thickness of the thermal and concentration layers was dramatically reduced, makingthese two kinds of deposition much faster.  相似文献   

The climatic impacts of land surface change and carbon management, and the implications for climate-change mitigation policy   总被引：4，自引：0，他引：4  

Gregg Marland  Roger A. Pielke Sr. 《Climate Policy》2003,3(2):149-157

Strategies to mitigate anthropogenic climate change recognize that carbon sequestration in the terrestrial biosphere can reduce the build-up of carbon dioxide in the Earth’s atmosphere. However, climate mitigation policies do not generally incorporate the effects of these changes in the land surface on the surface albedo, the fluxes of sensible and latent heat to the atmosphere, and the distribution of energy within the climate system. Changes in these components of the surface energy budget can affect the local, regional, and global climate. Given the goal of mitigating climate change, it is important to consider all of the effects of changes in terrestrial vegetation and to work toward a better understanding of the full climate system. Acknowledging the importance of land surface change as a component of climate change makes it more challenging to create a system of credits and debits wherein emission or sequestration of carbon in the biosphere is equated with emission of carbon from fossil fuels. Recognition of the complexity of human-caused changes in climate does not, however, weaken the importance of actions that would seek to minimize our disturbance of the Earth’s environmental system and that would reduce societal and ecological vulnerability to environmental change and variability.  相似文献   

冀北张麻井铀钼矿床黄铁矿化蚀变岩地球化学迁移特征及与成矿关系亲缘性的讨论     

宋凯  巫建华  郭恒飞  郭国林 《高校地质学报》1997,25(3):352

张麻井铀钼矿床是中国北方最大的与火山岩有关的热液铀矿床，围岩蚀变广泛发育，其中黄铁矿化在该矿床分布虽 较为局限，但是与铀钼成矿关系密切。为了研究黄铁矿化蚀变与铀、钼成矿的亲缘关系，文章对张麻井的黄铁矿化蚀变岩 进行主、微量元素分析，并选择Yb作为不活动组分，使用质量平衡迁移计算方法， 利用Grant公式对其组分迁移进行定量 计算。岩石地球化学特征显示，黄铁矿化蚀变岩的TFeO含量极高，介于11.24%~24.57%之间(平均18.45%)，其中Fe2O3含量 10.78%~25.25% （平均18.64%）、FeO含量1.43%~1.90% （平均1.69%），Fe2O3/FeO比值平均为10.99，有可能受到后期氧 化。黄铁矿化蚀变岩在Isocon图解上等浓度线斜率小于1，表明整体发生了组分的带入，带入的主要组分为大量的TFeO （131倍），成矿元素Mo（884倍）、Pb（11倍）、U（4.9倍）、V（2.8倍）、Ta（0.44倍）、Cu（0.64倍），碱金属Na2O（0.45 倍），以及Cd（424倍）、Bi（13倍） 等；带出的主要组分有碱金属Li（-0.73）、K2O（-0.17），成矿元素Zn（-0.38）、Cr （-0.37），以及Eu（-0.58）、Sc（-0.25） 等。其中SiO2略微减少（-0.03），带入的Mo含量远大于U的含量，据此认为黄铁 矿化与钼成矿关系更为密切。  相似文献   

Using rainfall-runoff modeling to interpret lake level data   总被引：2，自引：0，他引：2  

Lars Bengtsson  Joakim Malm 《Journal of Paleolimnology》1997,18(3):235-248

Using water balance computations, the behavior of different kinds of lakes is discussed. Simple analytical expressions relating water level to hydrological conditions and lake bathymetry are given. The importance of knowing the river basin area when analyzing lake levels is stressed. A conceptual rainfall-runoff model including lake routing is used to simulate runoff and lake levels and to compute quasi-steady state conditions and long-term transient situations. It is suggested that models can be used to construct curves relating lake levels to precipitation and lake evaporation. By comparing with paleo-lake levels, the annual precipitation related to these levels can be found, provided information is available about the seasonal distribution of the precipitation.  相似文献   

中国硫的供求现状和展望   总被引：1，自引：0，他引：1  

范可正  林乐 《化工矿产地质》1996,18(4):317-324

从工业和农业两个方面供需现状分析，中国目前硫的供需基本平衡，且供略大于求。展望２０００年，中国硫的供求关系将出现缺口，需进一步开拓硫的潜在资源。从总体上看，目前中国土壤供硫情况尚好，但一些地区已开始出现缺硫和严重缺硫的状况，预测今后土壤缺硫状况将会加剧，希望各有关部门对此应给予充分注意  相似文献