华盛顿美国国家气象中心的数值预报模式和“人机结合”

一、前言现代技术以及对数值天气预报科学运用方面的进展,使许多现代的国家气象局的天气预报工作起了革命性的变化。世界上主要天气中心的预报员们利用计算机,得到最准确、最有效益的预报,而“人机结合”方法,往往是这种预报系统的核心,显然各中心的“人机结合”不同,而且在不断变动,但对数值预报的使用得到了不断地、广泛地改进。     

选矿中金矿物学平衡的意义

本文研讨了在详细地设计冶炼实验和处理难选金矿石的最佳条件中,金矿物学平衡的意义。通过对32个金矿石和含金矿石的实验而得到了一个完整的定量化的矿物学平衡程序。这个平衡程序是以特殊的氧化作用用鉴定可见金的百分比和用光学显微镜及电子探针测定金矿物的特征为基础提出的。不可见金即胶体粒级金和固体中的金,这两者直接用氧化作用选剔测定效果不佳,用定量的离子探针微区分析(SIMS)可直接测定。这样就直接测定了所有的载金矿物,鉴定结果准确无误。本文选择五个例子作了介绍。目的之一是提供一个体系——通过鉴定金的赋存形式来研究金的矿物学程序,并有助于设计和优化选矿工艺过程。     

Evidence for Differential Unroofing in the Adirondack Mountains, New York State, Determined by Apatite Fission-Track Thermochronology

Apatite fission-track ages of 168-83 Ma for 39 samples of Proterozoic crystalline rocks, three samples of Cambrian Potsdam sandstone, and one Cretaceous lamprophyre dike from the Adirondack Mountains in New York State indicate that unroofing in this region occurred from Late Jurassic through Early Cretaceous. Samples from the High Peaks section of the Adirondack massif yielded the oldest apatite fission-track ages (168-135 Ma), indicating that it was exhumed first. Unroofing along the northern, northwestern, and southwestern margins of the Adirondacks began slightly later, as shown by younger apatite fission-track ages (146-114 Ma) determined for these rocks. This delay in exhumation may have resulted from burial of the peripheral regions by sediment shed from the High Peaks. Apatite fission-track ages for samples from the southeastern Adirondacks are distinctly younger (112-83 Ma) than those determined for the rest of the Adirondack region. These younger apatite fission-track ages are from a section of the Adirondacks dissected by shear zones and post-Ordovician north-northeast-trending normal faults. Differential unroofing may have been accommodated by reactivation of the faults in a reverse sense of motion with maximum compressive stress, sigma1, oriented west-northwest. A change in the orientation of the post-Early Cretaceous paleostress field is supported by a change in the trend of Cretaceous lamprophyre dikes from east-west to west-northwest.     

美国和加拿大的非联邦自动气象站（网）

1 引言 80年代美国和加拿大的非联邦自动气象站(AWS)和自动气象站网的数量,出现了惊人的增加。加利福尼亚、明尼苏达、内布拉斯加、北卡罗来纳和俄亥俄等州,都是70年代末80年代初首先建立非联邦AWS网的州。到1983年底,科罗拉多、佛罗里达、爱达荷、路易斯安娜、新墨西哥、纽约、     

由 CDSN 记录计算出的谱震级和地震辐射能

用10个数字化台的宽频带数字记录,计算了1986至1989年间发生在欧亚地震带上的18次 Ms6地震的谱震级和地震辐射能.10个数字化台中有9个属于中国数字化地震台网(CDSN),1个属于德国格拉芬堡台阵.计算得到的不同周期的谱震级,有的稳定性较好,有的稳定性较差.最大谱震级 mf和地震辐射能 E 稳定性较好,各台之间差异很小.特别是对于震中距较大,射线主要通过下地幔的台站,稳定性更好.而拐角周期的稳定性一般较差.辐射能与矩震级的关系满足lgE=1.5Mw+C,C 为常数.最大谱震级 mf=Mw+0.1,与理论预测值一致.      

Comparison of approaches for predicting solute transport: sandbox experiments

The main purpose of this paper was to compare three approaches for predicting solute transport. The approaches include: (1) an effective parameter/macrodispersion approach (Gelhar and Axness 1983); (2) a heterogeneous approach using ordinary kriging based on core samples; and (3) a heterogeneous approach based on hydraulic tomography. We conducted our comparison in a heterogeneous sandbox aquifer. The aquifer was first characterized by taking 48 core samples to obtain local-scale hydraulic conductivity (K). The spatial statistics of these K values were then used to calculate the effective parameters. These K values and their statistics were also used for kriging to obtain a heterogeneous K field. In parallel, we performed a hydraulic tomography survey using hydraulic tests conducted in a dipole fashion with the drawdown data analyzed using the sequential successive linear estimator code (Yeh and Liu 2000) to obtain a K distribution (or K tomogram). The effective parameters and the heterogeneous K fields from kriging and hydraulic tomography were used in forward simulations of a dipole conservative tracer test. The simulated and observed breakthrough curves and their temporal moments were compared. Results show an improvement in predictions of drawdown behavior and tracer transport when the K tomogram from hydraulic tomography was used. This suggests that the high-resolution prediction of solute transport is possible without collecting a large number of small-scale samples to estimate flow and transport properties that are costly to obtain at the field scale.