地震活动性的细胞自动机模型

本文在二维平面设计了一个模拟地震活动性的细胞自动机模型，分析了模拟地震离列的活动性，并探讨了强震前场兆和源兆的物理机制，结果表明，模型的地震序列很好地反映了实际地震的丛集特性、幂律关系和空间转移概率的稳定性等特点。     

1901-1995年气候变化导致陆地生态系统净吸收碳

The spatial and temporal variability of land carbon flux over the past one hundred years was investigated based on an empirical model directly calculating soil respiration rate. Our model shows that during 1901-1995, about 44-89 PgC (equals to 0.5, 0.9 PgC/yr respectively) were absorbed by terrestrial biosphere. The simulated net ecosystem productivity (NEP) after the 1930s was close to the estimated value of" missing C sink” from deconvolution analysis. Most of the total carbon sink happened during 1951-1985 with the estimated value of 33-50 PgC. Three major sinks were located in the tropics (10°S-10°N), Northern mid-latitudes (30°-60°N) and Southern subtropics (10°-40°S). During 1940s-mid-1970s, carbon sinks by terrestrial ecosystem increased with time, and decreased after the mid-1970s. These may be due to the ch anging of climate condition, as during the 1940s-1970s, temperature decreased and precipitation increased, while after the mid-1970s, an opposite climate situation occurred with evident increasing in temperature and decreasing in precipitation. Usually, warmer and dryer climate condition is not favor for carbon absorption by biosphere and even induces net carbon release from soil, while cooler and wetter condition may induce more carbon sink. Our model results show that the net carbon flux is particularly dependent on moisture / precipitation effect despite of temperature effect. The changing of climate in the past century may be a possible factor inducing increases in carbon sink in addition to CO2 and N fertilizer.     

Landslides in the Central Coalfield (Cantabrian Mountains, NW Spain): Geomorphological features, conditioning factors and methodological implications in susceptibility assessment

A geomorphological study focussing on slope instability and landslide susceptibility modelling was performed on a 278 km² area in the Nalón River Basin (Central Coalfield, NW Spain). The methodology of the study includes: 1) geomorphological mapping at both 1:5000 and 1:25,000 scales based on air-photo interpretation and field work; 2) Digital Terrain Model (DTM) creation and overlay of geomorphological and DTM layers in a Geographical Information System (GIS); and 3) statistical treatment of variables using SPSS and development of a logistic regression model. A total of 603 mass movements including earth flow and debris flow were inventoried and were classified into two groups according to their size. This study focuses on the first group with small mass movements (10⁰ to 10¹ m in size), which often cause damage to infrastructures and even victims. The detected conditioning factors of these landslides are lithology (soils and colluviums), vegetation (pasture) and topography. DTM analyses show that high instabilities are linked to slopes with NE and SW orientations, curvature values between − 6 and − 0.7, and slope values from 16° to 30°. Bedrock lithology (Carboniferous sandstone and siltstone), presence of Quaternary soils and sediments, vegetation, and the topographical factors were used to develop a landslide susceptibility model using the logistic regression method. Application of “zoom method” allows us to accurately detect small mass movements using a 5-m grid cell data even if geomorphological mapping is done at a 1:25,000 scale.     

Identifying linear and non-linear behaviour in reduced complexity modelling output using surrogate data methods

Validation of model output is an important issue in the environmental sciences. This is particularly the case for reduced complexity modelling approaches where verification of the underlying equations is often problematic. Hence, methods that go beyond validation based on average values or the histogram of model output, are clearly advantageous. In this paper we show that a validation method based on the serial properties of time–space data, and developed in geomorphology, is a useful alternative but is nevertheless still insensitive to certain asymmetric characteristics of the signal. Hence, use of this method for validation may be enhanced by the adoption of an accompanying test for asymmetry in the model output.     

Performance of surface footing on geocell-reinforced soft clay beds

This paper presents the results of laboratory model tests carried out to develop an understanding of the behaviour of geocell-reinforced soft clay foundations under circular loading. Natural silty clay was used in this study. The geocells were prepared using biaxial polymer grid. The performance of the reinforced bed is quantified using non-dimensional factors i.e., Bearing capacity improvement factor (I_f) and Percentage reduction in footing settlement (PRS). The test results demonstrate that the geocell mattress redistributes the footing load over a wider area thereby improving the performance of the footing. The load carrying capacity of the clay bed is increased by a factor of up to about 4.5 times that of unreinforced bed. From the pressure-settlement responses, it is observed that the geocell-reinforced foundation bed behaves as a much stiffer system compared to the unreinforced case indicating that a substantial reduction in footing settlement can be achieved by providing geocell reinforcement in the soft clay bed. The maximum reduction in footing settlement obtained with the provision of geocell mattress of optimum size placed close to the footing is around 90%. Further improvement in performance is obtained with provision of an additional planar geogrid layer at the base of the geocell mattress.     

地形RSG模型的动态构网算法

论述了一种基于规则格网地形模型的动态构网算法。通过定义模型中顶点间的约束关系以及顶点误差的继承方法，利用四叉树构建出顶点的层次结构，有效解决了不同分辨率网络间接边的裂缝问题，实现在模型误差控制下的多分辨网络的实时正确构网。实验证明，该方法对于实时控制地形模型的细节层次，增强地形模型的绘制效率是非常有效的。     

3维GIS面向对象数据模型的研究与应用

3维数据模型是3维GIS研究中亟待解决的一个核心问题。在充分分析现有3维数据模型的基础上，从实际应用出发，针对传统模型的不足，提出1种3维GIS面向对象数据模型，以解决空间不规则实体本身，以及实体间复杂关系的描述、表达和组织等关键问题，并给出此模型应用实例，证明此模型的可行性和实用性。     

宾川幔坳区斑岩铜矿综合信息三维找矿模型

云南宾川幔坳区位于青藏高原横断山脉东缘，金沙江有色贵金属矿带南段，是云南仅次于东川-昭通，个旧-丘北的第三大幔坳区，本文首次概括综合信息三维找矿模型显示，该区可能赋存一个超大型斑岩系列铜矿床，区内纳米碳，铜，金相互作用是其主要成矿作用之一。