铀矿层真实厚度的确定和最佳测井点距

本文讨论了最佳测井点距的选择原理,其最佳值大致为8-12.5cm.并从原理上分析了矿层解释厚度增大的主要原因:根据离散测量值所作的分层解释结果必然导致矿层解释厚度的增大.大量的模型测量结果完全证实了理论分析的正确性,并且还提出了合适的解决办法.     

对称化测量高频电磁波测井的优化组合研究

采用对称化测量可克服现有单发双收高频电磁波测井仪器（ＤＰＴ）由于收－发不对称结构导致的幅度比测井曲线严重失真的缺陷，提高ＤＰＴ的纵向分辨率．通过对二线非均质测井环境下ＤＰＴ响应的数值模拟，指出选用原频率较低、源距较长仪器的相位差测量与源频率较高、源距较短仪器的幅度比测量进行组合，可获得高品质的视介电常数和视电阻率曲线，显著提高ＤＰＴ的资料解释能力．这里源频率的恰当选择起着关键作用．     

Improving the efficiency of ant algorithms using adaptive refinement: Application to storm water network design

The ant algorithm is a new evolutionary optimization method proposed for the solution of discrete combinatorial optimization problems. Many engineering optimization problems involve decision variables of continuous nature. Application of the ant algorithm to the optimization of these continuous problems requires discretization of the continuous search space, thereby reducing the underlying continuous problem to a discrete optimization problem. The level of discretization of the continuous search space, however, could present some problems. Generally, coarse discretization of the continuous design variables could adversely affect the quality of the final solution while finer discretization would enlarge the scale of the problem leading to higher computation cost and, occasionally, to low quality solutions. An adaptive refinement procedure is introduced in this paper as a remedy for the problem just outlined. The method is based on the idea of limiting the originally wide search space to a smaller one once a locally converged solution is obtained. The smaller search space is designed to contain the locally optimum solution at its center. The resulting search space is discretized and a completely new search is conducted to find a better solution. The procedure is continued until no improvement can be made by further refinement. The method is applied to a benchmark problem in storm water network design discipline and the results are compared with those of existing methods. The method is shown to be very effective and efficient regarding the optimality of the solution, and the convergence characteristics of the resulting ant algorithm. Furthermore, the method proves itself capable of finding an optimal, or near-optimal solution, independent of the discretization level and the size of the colony used.     

在Zebiak-Cane模式中观测MJO强迫对ENSO可预报性的影响, 第1部分:对最大预报误差的影响

With the observational wind data and the Zebiak-Cane model, the impact of Madden-Julian Oscillation (MJO) as external forcing on El Ni(n)o–Southern Oscillation (ENSO) predictability is studied. The obs...     

中国雨季的一种客观定量划分

从客观分析角度出发,利用有序样本最优分割法对中国610个台站的气候平均（1961—2010年）候降水序列进行有序分割,给出中国不同区域的雨季定量划分。根据中国13个区域候降水量的气候平均值分布特征,并基于有序样本最优分割法的划分结果需同时满足分割段内波动小、段间差异大的要求,确定了各区域的合理分割数,通过制定3种雨季划分方案,对中国区域雨季进行了细致的定量划分。第1种方案将全年降水划分为雨季和旱季,结果表明,雨、旱两季差异明显的地区出现在华南西部沿海和新疆邻近区域;第2种方案将全年降水划分为雨季相对干期、雨季相对湿期和旱季3个降水阶段,这种特征出现的区域为华南大部分地区、江南地区、长江中下游地区、西南地区东部和南部,以及西北地区中东部;第3种方案将全年降水划分为春雨季、主雨季、秋雨季和旱季,出现这种特征的区域为长三角及淮河流域、黄淮和华北地区、东北地区、西北地区中部、内蒙古地区西部、青藏高原中东部及其以东地区。与已有的中国不同区域降水特征研究结果的比较表明,有序样本最优分割法不仅对中国雨季的划分客观有效,且其划分结果合理并具有明确的气象意义。     

条件非线性最优扰动在可预报性问题研究中的应用

本文总结了近年来条件非线性最优扰动方法的应用研究的主要进展.主要包括四个方面:(1)将条件非线性最优扰动(CNOP)方法拓展到既考虑初始扰动又考虑模式参数扰动,形成了拓展的CNOP方法.拓展的CNOP方法不仅能够应用于研究分别由初始误差和模式参数误差导致的可预报性问题,而且能够用于探讨初始误差和模式参数误差同时存在的情形;(2)将拓展的CNOP方法分别应用于ENSO和黑潮可预报性研究,考察了初始误差和模式参数误差对其可预报性的影响,揭示了初始误差在导致ENSO和黑潮大弯曲路径预报不确定性中的重要作用;(3)考察了阻塞事件发生的最优前期征兆(OPR)以及导致其预报不确定性的最优增长初始误差(OGR),揭示了OPR和OGR空间模态及其演变机制的相似性及其局地性特征;(4)研究了台风预报的目标观测问题,用CNOP方法确定了台风预报的目标观测敏感区,通过观测系统模拟试验(OSSEs)和/或观测系统试验(OSEs),表明了CNOP敏感区在改进台风预报中的有效性.具体地,台风OGR的主要误差分布在某一特定区域,空间分布具有明显的局地性特征,在台风OGR的局地性区域增加观测,有效改进了台风的预报技巧,该区域代表了台风预报的初值敏感区.事实上,上述El Ni(n)o事件、黑潮路径变异以及阻塞事件的OGR的空间分布也具有明显的局地性特征,这些事件的OGR刻画的局地性区域可能也代表了初值敏感区.     

区域地下水动态观测网优化的组合克立金方法

本文推导出了普通二变量及泛二变量组合克立金方程式．同时，给出了两种方法的估计误差标准差求解方程，可用于地下水动态观测网的密度优化；该方法还可用于地下水位、水中离子浓度的最优估计．     

THE QUALITY OF MEAN AND VARIANCE ESTIMATES FOR NORMAL AND LOGNORMAL DATA WHEN THE UNDERLYING DISTRIBUTION IS MISSPECIFIED

Theoretical and simulation results are employed to evaluate mean and variance estimaies for normal datawhen a lognormal distribution is assumed and for lognormal data when a normal distribution is assumed.Misspecifying the distribution leads to the use of suboptimal estimation methods.However,the resultsshow that the suboptimal methods still produce estimators of good quality(low bias and variance)relativeto the minimum variance unbiased estimators for each distribution,at least when practical efficiency isconsidered.     

Optimization of mooring observations in Northern Bering Sea

The problem of the optimal sampling strategy for moored current velocity observations in the Northern Bering Sea is addressed. We analyze dynamically induced correlations in the North Bering Sea currents and conduct their sensitivity analysis to optimize positions of a limited number of moorings. Optimization of the sampling strategy is performed with respect to robustness of the reconstruction of the North Bering Sea circulation with a particular emphasis on the accurate monitoring of the mean Bering Strait transport. Computations reveal four major regions in the North Bering Sea basin that are highly correlated with the Bering Strait transport. Apart from the regions within the Bering Strait itself, they include the Anadyr Strait and a region 100 km south of the Cape of Prince of Wales. Results of the sensitivity analysis are tested in the framework of twin data experiments with the quasi-stationary and oscillatory background circulations.