基于遥感的长沙市城市热岛效应时空分析

利用TM/ETM+数据,以长沙市为例,反演了地表温度,并针对不同时相的遥感数据,利用城市热岛强度来反映热岛效应强弱的变化。结果表明,长沙市的热岛空间分布与城市建成区的轮廓相吻合。城市热岛的范围随着城市建设、新建开发区以及道路交通网的发展不断增大,且在东南方向为主要增长方向。根据热岛强度鉴别并提取了强热岛区与正常区,发现长沙市强热岛区的面积已经从1993年的13.18km2扩大至2008年的68.16km2。最后,对长沙市热岛未来的发展趋势进行了预测。     

基于GIS的村镇建设用地节地效果评价系统

针对目前村镇建设用地集约节约利用效果评价方法空缺及信息化低等问题,依据村镇建设用地节约集约利用效果评价模型,在地理信息系统组件技术和数据库技术支持下,采用可视化编程语言MicrosoftC#.net和GIS控件技术开发了村镇建设用地节约集约利用效果评价系统。以太仓市陆渡镇为开发案例,探讨了系统分析、设计和功能实现等主要技术问题。并利用该系统对太仓市陆渡镇村镇建设用地集约节约利用效果评价进行了评价,评价结果表明,该系统能够满足当前村镇建设用地集约节约利用效果评价工作的需要,为快速准确地实施节地效果评价提供技术支持。     

The CM-SAF operational scheme for the satellite based retrieval of solar surface irradiance — A LUT based eigenvector hybrid approach

The radiation budget at the earth surface is an essential climate variable for climate monitoring and analysis as well as for verification of climate model output and reanalysis data. Accurate solar surface irradiance data is a prerequisite for an accurate estimation of the radiation budget and for an efficient planning and operation of solar energy systems.This paper describes a new approach for the retrieval of the solar surface irradiance from satellite data. The method is based on radiative transfer modelling and enables the use of extended information about the atmospheric state. Accurate analysis of the interaction between the atmosphere, surface albedo, transmission and the top of atmosphere albedo has been the basis for the new method, characterised by a combination of parameterisations and “eigenvector” look-up tables. The method is characterised by a high computing performance combined with a high accuracy. The performed validation shows that the mean absolute deviation is of the same magnitude as the confidence level of the BSRN (Baseline Surface Radiation Measurement) ground based measurements and significant lower as the CM-SAF (Climate Monitoring Satellite Application Facility) target accuracy of 10 W/m². The mean absolute difference between monthly means of ground measurements and satellite based solar surface irradiance is 5 W/m² with a mean bias deviation of − 1 W/m² and a RMSD (Root Mean Square Deviation) of 5.4 W/m² for the investigated European sites. The results for the investigated African sites obtained by comparing instantaneous values are also encouraging. The mean absolute difference is with 2.8% even lower as for the European sites being 3.9%, but the mean bias deviation is with − 1.1% slightly higher as for the European sites, being 0.8%. Validation results over the ocean in the Mediterranean Sea using shipboard data complete the validation. The mean bias is − 3.6 W/m² and 2.3% respectively. The slightly higher mean bias deviation over ocean is at least partly resulting from inherent differences due to the movement of the ship (shadowing, allocation of satellite pixel). The validation results demonstrate that the high accuracy of the surface solar irradiance is given in different climate regions. The discussed method has also the potential to improve the treatment of radiation processes in climate and Numerical Weather Prediction (NWP) models, because of the high accuracy combined with a high computing speed.     

CBERS-02星CCD数据土地利用分类方法研究——以江苏省宜兴地区为例

以江苏省宜兴地区为试验区,首先进行了CBERS-02星CCD数据的图像预处理,然后利用ERDASI-MAGINE和Definiens7.0等软件,采用非监督分类、监督分类、混合监督分类、面向对象四种分类方法进行了土地利用分类,并将影像分类结果进行了精度评价分析。结果表明：在一级地类的提取中,面向对象的最邻近分类器的分类精度最低,混合监督分类的精度最高;在二级地类的提取中,面向对象的特征阈值法得到的分类结果较好,能够轻松提取传统分类方法难于提取的地类。     

县级尺度农村居民点景观格局时空分异研究——以徐州市睢宁县为例

以TM/ETM＋影像为基础数据源,基于3S技术及景观分析软件Fragstats对1995-2005年徐州市睢宁县的农村居民点景观格局进行动态分析,并使用马尔科夫模型对睢宁县2010年农村居民点景观格局进行预测。结果表明：1995-2010年徐州市睢宁县的农村居民点景观格局呈破碎化趋势,土地利用斑块数增加,斑块平均面积下降,面积加权平均形状指数上升,平均分维度小幅上升,散布与并列指数和香农多样性指数均在下降。随着城镇扩展、农田开发等人类干扰的不断加剧,景观生态环境保护与经济开发之间的矛盾将愈加突出。     

WorldView卫星16波段影像光谱特征分类

传统的高分辨率遥感卫星光谱分辨率较低,WorldView卫星在8个可见光G近红外多光谱波段的基础上,新增加的８个短波红外(short wave infrared,SWIR)影像,有助于提高影像提取地物信息能力。分析了WorldView卫星的16波段影像上各种地物的光谱特征和分类性能,提出了新的植被指数、水体指数和建成区指数。实验表明,相比于8波段影像,使用16波段影像分类能够显著提高各类地物特别是裸地、建筑物和道路的分类精度,总体精度提高约5.5％。基于16波段设计的新地物特征指数能更好地避免干扰地物,通过简单阈值提取地物,取得较高的提取精度。     

基于Linux3S的土地基础信息采集技术

针对现有土地基础信息获取手段存在的一些缺陷,提出基于Lin“平台的、结合3S技术的土地基础信息采集方法。采用以Linux平台为核心,设计具有自主知识产权的嵌入式GIS模块,为适应在掌上电脑中使用,提出四叉树——双缓冲存取模式,以提高电子地图显示速度,利用四叉树分割法,实现大型底图显示,集成上层土地管理软件,实现土地基础数据采集。该技术在示范应用中实现取得良好效果,证明了该技术的有效性。     

基于学习分类器的自主地面车在狭隘环境中的路径规划

提出了一种基于学习分类器(LCS)的避碰路径规划方法,设计了集成适应度函数,在确保安全避碰的前提下,解决自主地面车(ALV)在狭隘环境下的路径优化问题.不同环境的仿真实验结果表明,遗传算法和学习分类器结合用于自主地面车的路径规划是收敛的,提高了ALV在狭隘环境中快速发现安全路径的能力.     

Modeling Instrumental Rationality, Land Tenure and Conflict Resolution

Full instrumental rationality and perfect institutions are two cornerstoneassumptions underlying neoclassical models. However, in the real world, thesetwo assumptions never hold, especially not in developing countries. In thispaper, we develop a game theoretical model to investigate if relaxations inthe full instrumental rationality and perfect institutions premise can explainthe conflicts that have been occurring between the various principals in theNarok district in Kenya with regard to land tenure and use.     

Calculating soil nutrient balances in Africa at different scales

Nutrient balances were calculated for the arable soils of 38 sub-Saharan African countries. FAO production figures and forecasts for 35 crops for the period 1982–1984 and for 2000 were used to define land use systems, further characterized by fertility input through fertilizers, manure, rain and dust, biological N-fixation, and sedimentation, and fertility output through harvest of crops and removal of residues, leaching, denitrification, and erosion. The summarized output of the study is the sum of inputs minus the sum of outputs of nitrogen, phosphorus and potassium in the root zone. The alarming annual average nutrient loss for sub-Saharan Africa was 22 kg N, 2.5 kg P, and 15 kg K in 1982–84, and will be 26 kg N, 3 kg P, and 19 kg K in 2000. As the soil nutrient pool has to offset the negative balances each year, there is gross nutrient mining in sub-Saharan Africa. The need for integrated systems of nutrient management is emphasized, manipulating all inputs and outputs in a judicious way. Future scenarios of continued mining and conservation of soil fertility are discussed.