虚拟地理环境中时态信息可视化表达方法研究

介绍虚拟地理环境的基本含义，虚拟现实和可视化技术，探讨了线、面地理对象的时态信息表达方法。在此基础上，以近、现代黄河三角洲为例，给出了在虚拟地理环境中三角洲海岸线的变迁和三角洲地形地貌动态显示的方法。     

点状地名的时空数据模型

概述了地名、地名数据库以及时空数据模型的定义及其发展现状,提出了适合地名时空语义表达的地名时空数据模型.应用这个模型实现了对地名数据库的编辑更新及时空查询操作.本文以地名为例研究了点状目标的时空数据模型,丰富了时空数据模型理论.     

Seasonal and secular positional variations at eight co-located GPS and VLBI stations

Time series of daily position solutions at eight co-located GPS and VLBI stations are used to assess the frequency features in the solutions over various time-scales. This study shows that there are seasonal and inter-annual signals in all three coordinate components of the GPS and VLBI solutions. The power and frequency of the signals vary with time, the station considered and the coordinate components, and between the GPS and VLBI solutions. In general, the magnitudes of the signals in the horizontal coordinate components (latitude and longitude) are weaker than those in the height component. The weighted means of the estimated annual amplitudes from the eight GPS stations are, respectively, 1.0, 0.8 and 3.6 mm for the latitude, longitude and height components, and are, respectively, 1.5, 0.7 and 2.2 mm for the VLBI solutions. The phases of the annual signals estimated from the GPS and VLBI solutions are consistent for most of the co-located stations. The seasonal signals estimated from the VLBI solutions are, in general, more stable than those estimated from the GPS solutions. Fluctuations at inter-annual time-scales are also found in the series. The inter-annual fluctuations are up to ∼5 mm for the latitude and longitude components, and up to ∼10 mm for the height component. The effects of the seasonal and inter-annual variations on the estimated linear rates of movement of the stations are also evaluated.     

On the interpretation of vertical gravity gradients produced by magmatic intrusions

A method for the computation and interpretation of gravity and height changes and vertical gravity gradients produced by magmatic intrusions in a layered elastic–gravitational medium is presented. The methodology assumes a planar medium geometry, which consists of welded layers overlying a half-space. The medium is elastic and gravitating. The intrusion is treated as a point source and can be located at any depth inside the medium. The theoretical elastic–gravitational model allows the computation of the so-called geometric and orthometric vertical displacements as well as gravity changes of different types. The corresponding vertical gravity gradients can also be computed. We present several examples of theoretical computations and study different types of these geometric and orthometric gravity gradients and the information we can get from the application of the methodology described. The results presented show that the use of these gradients is a useful tool to obtain information on the dynamics of the injection processes, including the detection of new magma recharge. We show that using the elastic–gravitational deformation model we can explain non-linear gravity–height relationships that appear in volcanic areas. We also present the application of the methodology to Mayon volcano, Philippines, delineating the intrusion of new magma, consistent with the produced eruptions after the observation period.     

新疆生态环境近期变化与应对措施的初步分析

新疆的生态安全已引起全社会的极大关注。作者依据近年几次考察和资料信息分析，分析了新疆生态环境近期变化的主要特点和引起变化的主要原因，强调指出新疆气候“暖湿”变化不可能从根本上改变新疆干旱地区生态环境的基本状态，对此不能盲目乐观，只能因势利导，抓住有利时机加大修复生态环境的力度。文中提出了五项加强新疆生态环境修复、保护和建设的应对措施。     

时空数据模型的N1NF关系基础

Ｎ１ＮＦ关系方法在处理非表格化的复杂结构对象时优于传统关系方法，因而适合于时态ＧＩＳ。本文讨论了空间对象的Ｎ１ＮＦ表达和操作，将空间，时间和属性结合为一个整体，与作者的前期工作一起构成了矢量式时空数据模型的Ｎ１ＮＦ关系基础；本文还初步讨论了建立在这个基础上的面状地理要素的时空数据模型。     

太阳总辐射最佳倾角的时空分布

本文根据倾斜面上太阳总辐最佳倾角的角析表示式，利用平均太阳总辐射和直接辐月总量以及实际地表面反射率，计算分析了我国各月最佳倾角和最佳总辐射比的时空变化特征。同时对用天空散射辐射各同性模式计算倾斜面上总辐日总量的适用性问题亦作了简要讨论。     

Clast size variations on talus: Some observations from northwest Ireland

Clast size variations are reported for a relict talus slope in northwest Ireland. Alternating longitudinal zones of coarse debris below buttresses and less coarse debris below gullies give the talus pronounced lateral variations in clast size that are related to joint spacing variations in the talus source area. Longitudinal variations in clast size are also present. The talus accumulated predominantly by the process of rockfall. Other processes frequently associated with lateral size variations were not significantly effective during talus development. Talus sliding may have modified some patterns of rockfall size grading.