安徽庐枞中生代富钾火山岩成因的地球化学制约   总被引：74，自引：7，他引：74  

刘洪  邱检生  罗清华  徐夕生  凌文黎  王德滋 《地球化学》2002,31(2):129-140

庐枞中生代火山岩产于下扬子断裂坳陷带的继承式火山盆地中，主要为一套以粗面玄武岩－玄武粗安岩－安粗岩－粗面岩为主体的偏碱质中基性岩石组合。化学成分上具有富碱、富钾、富轻稀土及大离子亲石元素（如Rb、Th、Pb)和贫高场强元素（如Nb、Ti)等特点。在郯庐断裂中南段及其邻近地区的中生代火山岩中，庐枞盆地火山岩的特征最接近钾玄岩系火山岩。这套火山岩具有较高的ISr值（0.70570-0.70653)及偏低的εNd(t)值（－5.01～-9.96)。火山岩产出地质背景的全面分析及元素－同位素的综合示踪，排除了岩浆上升过程中存在强烈的地壳物质的混染，富钾火山岩的岩浆源区应为受俯冲板片析出流体交代作用所形成的富集地幔（EMI），岩石主要起源于富集型地幔的部分熔融。  相似文献   

鄂尔多斯盆地上古生界储层中包裹体最小捕获压力的PVTsim模拟   总被引：9，自引：1，他引：9  

米敬奎  肖贤明  刘德汉  申家贵 《地球化学》2002,31(4):402-406

应用传统的方法求取包裹体的捕获压力存在许多问题。近几个发展起来的PVTsim软件已广泛应用于计算机含油气盆地中液态烃包裹体的捕获压力，然而利用该软件缺乏液态烃包裹体的天然气藏储层中包裹体的捕获压力的文章尚未见报道。在对鄂尔多斯盆地上古生界储层砂岩中次生盐水包裹体进行有关测定和分析的基础上，利用PVTsim软件对该类包裹体捕获压力进行了模拟计算。结果表明，包裹体的最小捕获压力为16－21MPa，并有从南向北逐渐减小的趋势，而且包裹体的捕获压力远小于深盆气藏形成时的静水压力，这一特征与深盆气藏形成的地质地球化学条件相一致。  相似文献   

Results from One-Year Continuous Operation of a Large Aperture Scintillometer over a Heterogeneous Land Surface   总被引：8，自引：0，他引：8  

F. Beyrich  H. A. R. De Bruin  W. M. L. Meijninger  J. W. Schipper  H. Lohse 《Boundary-Layer Meteorology》2002,105(1):85-97

A large-aperture scintillometer (LAS) was operated continuouslyduring a period of more than one year over a heterogeneous land surface in Central Europeat the transition between marine and continental climates. The LAS measurements of the refractiveindex structure parameter, C_N ², were used to estimate the sensible heat flux. Thiswas possible for about 60to 80% of the time under daytime conditions during thesummer, with lower values obtained for the cold season (October to March). Using datafrom a three-week long field experiment, the LAS-based heat flux was compared with a weighedaverage of local heat flux measurements over the main land use classes (forest, agriculture,water) in the area, resulting in reasonable agreement. LAS-based heat fluxes were then used forcomparison with the heat flux values of a numerical weather prediction model. An over-predictionof the model heat flux was found in summer but the modelled values were lower than the LASderived data during the cold season.  相似文献   

An Extra Large Aperture Scintillometer For Long Range Applications   总被引：3，自引：1，他引：3  

W. Kohsiek  W. M. L. Meijninger  A. F. Moene  B. G. Heusinkveld  O. K. Hartogensis  W. C. A. M. Hillen  H. A. R. De Bruin 《Boundary-Layer Meteorology》2002,105(1):119-127

An incoherent scintillometer with 0.31-m aperture was testedalong a 9.8-km path over grassland. Scintillometer derived heat fluxes were comparedwith in situ eddy covariance measurements. Albeit with considerable scatter, the fluxescompared well during daytime. During nighttime credible fluxes are also obtained. The scintillometerfunctioned satisfactory for 96% of the 7-week period.  相似文献   

Determination of Area-Averaged Sensible Heat Fluxes with a Large Aperture Scintillometer over a Heterogeneous Surface – Flevoland Field Experiment     

W. M. L. Meijninger  O. K. Hartogensis  W. Kohsiek  J. C. B. Hoedjes  R. M. Zuurbier  H. A. R. De Bruin 《Boundary-Layer Meteorology》2002,105(1):37-62

To test the applicability of the scintillation method over a heterogeneous area an experiment was carried out in the summer of 1998 in Flevoland (The Netherlands). In the patchy area only four crops were grown namely sugar beet, potatoes, wheat and onions. From eddy covariance measurements it was found that the heterogeneity was mainly caused by differences in thermal properties. No variations in the aerodynamics roughness length were observed. Two large aperture scintillometers were installed at a height of 11.6 and 20.4 m. A good resemblance was found between the sensible heat fluxes derived from both LAS instruments and the area-averaged fluxes obtained from the in-situ eddy covariance measurements. The slight underestimation of the lower LAS could be assessed using a blending height model and an analytical footprint model. The results also indicated that when scintillometer measurements are made below the blending height the violation to Monin–Obukhov Similarity Theory is small and that reasonable fluxes can be obtained from path-averaged structure parameters.  相似文献   

Waves to the lee of a meso-scale elliptic orographic barrier     

S. Dutta  M. Maiti  U. S. De 《Meteorology and Atmospheric Physics》2002,81(3-4):219-235

Summary ?The paper considers a meso-scale, adiabatic, inviscid and Boussisnesq flow of a stably stratified fluid over a three-dimensional (3-D) meso-scale orographic barrier with elliptic contour, with special reference to a part of the Western ghats mountain along west coast of India and on the Khasi-Jayantia hill in the northeast India. The airstream characteristics are simplified by assuming that the upstream wind velocity (U) and buoyancy frequency (N) are constant with height. Solutions for perturbation vertical velocity (w′) and streamline displacement (η′) are expressed in terms of double integrals. These integrals cannot be evaluated exactly, hence they have been approximated by asymptotic expansion method. Side by side solutions using numerical method have also been obtained. The results of the study indicate that the updraft regions in the asymptotic solution are crescent shaped, symmetrical about the axis y = 0, tilting upwind and spreading laterally with height. The study also shows that in both asymptotic solution and numerical solution w′ and η′ fall off down wind of the barrier in the central plane (y = 0), further more in the asymptotic solution w′ and η′ fall off as x ⁻¹. The study also indicates that the discrete updraft regions obtained in the numerical solution, when joined, take a crescent shape. Received November 26, 2001; accepted February 27, 2002  相似文献   

兰州市低空风时空变化特征及其与空气污染的关系   总被引：7，自引：9，他引：7  

刘宇  王式功  尚可政  杨德保  祁斌 《高原气象》2002,21(3):322-326

对1988年至1992年兰州市环境监测站自动监测系统监测到的近地面逐时风和空气污染浓度资料以及对应时段的兰州市低空风资料乃至城，郊近40年的地面风资料做了深入的分析，并将城区与郊区对照点（榆中站）进行对比研究，揭示了风向频率变化特征和风速日变化，年变化，年际变化以及风随高度的变化规律。同时分析了对应时段空气污染的分布状况及其与风速的相关关系，为研究兰州市边界层大气动力稳定度的时空变化规律和开展空气污染预报提供了一定的依据。  相似文献   

Convergence of realization-based statistics to model-based statistics for the LU unconditional simulation algorithm: some numerical tests     

S. De Iaco  M. Palma 《Stochastic Environmental Research and Risk Assessment (SERRA)》2002,16(5):333-341

 In geostatistics, stochastic simulation is often used either as an improved interpolation algorithm or as a measure of the spatial uncertainty. Hence, it is crucial to assess how fast realization-based statistics converge towards model-based statistics (i.e. histogram, variogram) since in theory such a match is guaranteed only on average over a number of realizations. This can be strongly affected by the random number generator being used. Moreover, the usual assumption of independence among simulated realizations of a random process may be affected by the random number generator used. Simulation results, obtained by using three different random number generators implemented in Geostatistical Software Library (GSLib), are compared. Some practical aspects are pointed out and some suggestions are given to users of the unconditional LU simulation method.  相似文献   

辽宁省防震减灾“九五”重点项目实施概况及建设成果     

蒋秀琴  张书栋  佟晓辉  卢群  单德华 《东北地震研究》2002,18(1):1-12

“九五”期间，辽宁省地震局按照中国地震局的统一部署，应用先进的数字技术、网络技术和计算机技术，对原有的前兆与地震观测的模拟技术系统进行了改造，新建了辽宁省地震信息网络系统和防震减灾指挥中心，这是辽宁省第一次这样大规模地对防震减灾技术系统进行建设和改造。本文对“九五”重点项目的任务、技术系统构成及建设成果进行了阐述。  相似文献   

闾阳-康平-梨树深地震测深剖面野外资料数字化的设计与实现     

白云  姜德录  吴小兵  翟文杰  李爱民 《东北地震研究》2002,18(2):51-56

通过分析闾阳－康平－梨树深地震测深剖面的观测设计、观测结果以及仪器系统特点，根据项目研究目的及要求，对该剖面的模拟记录进行了数字化设计与实现，以满足用新方法对资料的进一步处理运算，并为资料的交流和永久保存打下了良好基础。  相似文献