广州市CORS系统的精度分析和应用

采用虚拟参考站技术,结合应用广州市似大地水准面精化成果;对系统进行了精度分析,并以实例说明该系统实现了实时三维城市定位的功能。     

多尺度非静力通用模式框架的设计策略

针对目前国际上数值预报模式的最新发展趋势,综述了新形势下多尺度非静力通用数值预报模式框架的设计策略。目前世界上开发通用模式主要有两个途经,一是建立一个离散化方案和源程序代码共享的、全球和有限区通用的模式,二是建立一个单一的全球可变分辨率的模式。还从通用模式方程组的选取策略、模式网格属性的构造,时间积分方案、空间离散方案,垂直坐标的选取等方面进行了分析。     

关于动力Alfven波的色散与朗道阻尼

根据完全动力论理论,证明了可由简化漂移动力论方程求得动力Ａｌｆｖｅｎ波色散方程,即横向用磁流体力学方程,纵向用Ｖｌａｓｏｖ方程,在初级近似下由此推导出适合于日冕和太阳风的色散关系和Ｌａｎｄａｕ阻尼,得到在性质上与ＭＨＤ　Ａｌｆｖｅｎ波完全不同的动力Ａｌｆｖｅｎ波,太阳风中Ａｌｆｖｅｎ湍流很容易由动力Ａｌｆｖｅｎ波演化而来。提出由动力Ａｌｆｒｅｎ波构筑太阳风高速流模型将更符合观测结果。     

Recent progress in estimating uncertainty in geomagnetic field modeling

Abstract

Recent work pertaining to estimating error and accuracies in geomagnetic field modeling is reviewed from a unified viewpoint and illustrated with examples. The formulation of a finite dimensional approximation to the underlying infinite dimensional problem is developed. Central to the formulation is an inner product and norm in the solution space through which a priori information can be brought to bear on the problem. Such information is crucial to estimation of the effects of higher degree fields at the Core-Mantle boundary (CMB) because the behavior of higher degree fields is masked in our measurements by the presence of the field from the Earth's crust. Contributions to the errors in predicting geophysical quantities based on the approximate model are separated into three categories: (1) the usual error from the measurement noise; (2) the error from unmodeled fields, i.e. from sources in the crust, ionosphere, etc.; and (3) the error from truncating to a finite dimensioned solution and prediction space. The combination of the first two is termed low degree error while the third is referred to as truncation error.

The error analysis problem consists of “characterizing” the difference δz = z—z, where z is some quantity depending on the magnetic field and z is the estimate of z resulting from our model. Two approaches are discussed. The method of Confidence Set Inference (CSI) seeks to find an upper bound for |z—?|. Statistical methods, i.e. Bayesian or Stochastic Estimation, seek to estimate E(δz² ), where E is the expectation value. Estimation of both the truncation error and low degree error is discussed for both approaches. Expressions are found for an upper bound for |δz| and for E(δz² ). Of particular interest is the computation of the radial field, B., at the CMB for which error estimates are made as examples of the methods. Estimated accuracies of the Gauss coefficients are given for the various methods. In general, the lowest error estimates result when the greatest amount of a priori information is available and, indeed, the estimates for truncation error are completely dependent upon the nature of the a priori information assumed. For the most conservative approach, the error in computing point values of B_r at the CMB is unbounded and one must be content with, e.g., averages over some large area. The various assumptions about a priori information are reviewed. Work is needed to extend and develop this information. In particular, information regarding the truncated fields is needed to determine if the pessimistic bounds presently available are realistic or if there is a real physical basis for lower error estimates. Characterization of crustal fields for degree greater than 50 is needed as is more rigorous characterization of the external fields.     

Under‐ice salinity and stable isotope distribution of Saroma‐ko Lagoon,Hokkaido, northern Japan

In winter, lakes and lagoons at high altitudes or high latitudes have interesting hydrological cycles that differ from those in other seasons or in other regions, because water surfaces are covered with ice. Hydrological balances of lakes and lagoons are complex dynamic systems, and to elucidate them, isotopic tracers of water have been used as effective tools along with observations of precipitation, evaporation, inflows, and outflows. Here, to understand hydrological processes during freezing periods in the brackish Saroma‐ko Lagoon, Hokkaido, northern Japan, we examined horizontal and vertical distributions of salinity and isotope compositions of lagoon water and ice in 2005 and 2006. Horizontal and vertical gradients of salinity and isotope compositions were observed from the river mouth to the sea channel, and factors determining these distributions were considered. The mixing of freshwater and seawater and a freezing effect were presumed to be factors in relationships between salinity and isotopes and in relationships between surface waters and ice just above the water. A simple box model for water balance was constructed based on these putative factors to reproduce the distributions of salinity and isotope compositions of surface waters and ice. An evaluation of the model revealed that this hydrological system is controlled primarily by horizontal advection of the epilimnion, freshwater influx, and the ice growth rate. Copyright © 2009 John Wiley & Sons, Ltd.     

Lateral tidal mixing in the Antarctic marginal seas

Tidal mixing plays an important role in the modification of dense water masses around the Antarctic continent. In addition to the vertical (diapycnal) mixing in the near-bottom layers, lateral mixing can also be of relevance in some areas. A numerical tide simulation shows that lateral tidal mixing is not uniformly distributed along the shelf break. In particular, strong mixing occurs all along the Ross Sea and Southern Weddell Sea shelf breaks, while other regions (e.g., the western Weddell Sea) are relatively quiet. The latter regions correspond surprisingly well to areas where indications for cross-shelf exchange of dense water masses have been found. The results suggest that lateral tidal mixing may account for the relatively small contribution of Ross Sea dense water masses to Antarctic Bottom Water.     

旋转触探数学模型及其试验分析

通过对旋转触探用双螺旋探头的受力分析,建立了螺旋探头的贯入阻力和扭矩与贯入速度和转速,以及岩土的力学性能参数间的数学模型。结合数学模型和试验数据对旋转触探技术的影响因素进行了分析,为设计探头结构和进一步理解该技术的力学机理提供了理论依据。     

基于AHP–物元可拓模型的顶板水疏放程度评价

为了科学合理地评价工作面顶板水疏放程度,分析了工作面涌水量预测值和疏放水观测值等要素,构建了顶板水疏放程度评价指标体系,划分了相应的评价等级标准,并利用AHP法确定了各评价指标的权重,建立了顶板水疏放程度的物元可拓模型。利用AHP-物元可拓模型对宁东煤田水文地质条件较为复杂的5个工作面顶板水疏放程度进行了评价,评价结果均为顶板水疏放程度好,并且各工作面已经实现了安全回采,实际情况与评价结果一致。AHP-物元可拓模型可以用于评价顶板水疏放程度,并且可以作为工作面采前水文地质条件评价的参考依据。     

冀西北水晶屯金矿F8断裂带深部定位预测

摘要：以冀西北水晶屯金矿为例,通过对该矿床Ｆ８断裂带成矿地质条件和找矿标志的分析研究,建立起了Ｆ８断裂带的地球化学原生晕模型和灰色系统ＧＭ（１．１）模型,并利用这些模型对其深部合矿性进行了预测．经工程验证,该预测效果是可信的．     

豫南火山岩型银多金属矿地质特征及成矿规律

从区域地质背景、矿带地质特征、典型矿床研究及稳定同位素等方面,论述豫南地区与中生代陆相火山岩有关的银多金属矿床地质特征,以及成矿与火山活动在时间、空间和成矿物质来源等方面的联系,总结了矿带成矿规律。研究认为,该成矿带属与燕山期陆相火山、次火山岩有关的银、铅、锌、金、钼成矿系列,并建立了成矿模式。在此基础上,提出了石山口破火山口南缘及沿龟梅断裂带两个金、银多金属矿的找矿方向。