作物叶面蒸腾与棵间蒸发分摊系数的计算方法

依据在冬小麦和玉米冠层表面及冠层内部下方土壤表面的净辐射观测资料,建立了一个能较准确地反映叶面蒸腾与棵间土壤蒸发分摊系数物理变化规律的较实用的计算模式,结果表明,分摊系数(α)随叶面积指数(LAI)增加而增加,且具有明显的日变化,α在中午最小、早、晚稍大,这种日变化受叶气孔调节的影响。     

矿山地理信息系统中的空间和时间四维数据模型

现有的许多地理信息系统（GISs）一般都没有考虑时间这一维数据。本文依据矿山的特点和需求，提出了能满足空间和时间要求的GIS的概念。针对传统数据模型所存在的缺点，以及根据处理历史数据所具有的特点，提出了一种用于矿业开发的空间和时间综合四维数据模型。这种模型通过采用四维空间线性编码技术，可大大减少数据存贮所需的辅助操作。为了适应综合四维数据处理的需要，笔者研究出了一种新的拓扑结构——四维空间和时间因素的拓扑关系。     

双等距离投影及其应用

双等距离投影是指自图上两定点出发至图上任意点间的距离都与实地等长的投影。本文先从球面极坐标出发，讨论了双等距离投影公式的建立，继而给出了在地理坐标下的正轴和斜轴投影计算方法。本文证明了该投影的性质属任意投影，其计算方法是可行的，有实用价值。双等距离投影在测量上可用于圆圆系统定位，在军事上可用于敌情监测等。     

试论我国现代地图学发展及其学科体系

现代地图学空间活跃，发展迅速，并在我国科技领域和国民经济建设中发挥着积极的作用。它已经成为一门涉及多领域的综合性学科。本文在分析现代地图学发展特点基础上，运用系统科学方法论，对现代地图学及其学科体系进行系统分析，提出了现代地图学学科体系的基本框架和对我国现代地图学发展及建立学科体系的几点认识和建议。     

Wavepath traveltime tomography

The elastic-wave equation is used to construct sensitivity kernels relating perturbations in elastic parameters to traveltime deviations. Computation of the functions requires a correlation of the forward-propagating seismic wavefield with a backward propagation of the residual wavefield. The computation of the wavefields is accomplished using a finite difference algorithm and is efficiently executed on a CM-2 parallel processor. The source and receiver locations have maximum sensitivity to velocity structure. The sensitivity kernels or wavepaths are well suited for transmission traveltime inversion such as cross-borehole tomography and vertical seismic profiling. Conventional ray tomography and wavepath tomography are applied to a set of P -wave arrival times, from a cross-borehole experiment at Kesterson, California. Because the wavepaths have increased sensitivity near the source and receiver there are differences in resolution of the velocity structure. Both techniques recover the same relative variations in velocity where the coverage is adequate. The wavepath solution is more laterally continuous and the dominant variation is vertical, as is expected for the layered sediments in this region.     

The magnetotelluric dispersion relations over 2-D structures

The causal properties of the magnetotelluric response, first derived by Weidelt, and Fischer & Schnegg in the 1-D limit, are confirmed numerically in the 2-D limit for the particular structure consisting of two uniform quarter spaces. This finding is of interest from several points of view: (1) the dispersion relations in their 1-D form seem to retain their validity for all 2-D tensor elements, irrespective of any rotation of the coordinate system chosen at the surface; in particular, (2) they appear equally valid for the E- and B-polarization configurations. (3) Whereas the question recently debated in the literature (whether the Earth can always be considered as a linear, passive and causal system) is perhaps not yet entirely resolved, the present empirical demonstration suggests that it may in general be safe to apply the 1-D dispersion relations to structures with 2-D character.     

Simple analytical Green's functions for ray perturbations in layered media

The total Green's function for two-point boundary-value problems can be related to the propagator for initial-value problems. A very simple expression for the Green's function is obtained when the unperturbed medium may be described by material with a constant gradient in quadratic slowness. The derivation requires a correct understanding of assumptions made in the propagator solution. Expressions are also obtained for Green's function in multilayered media.