Modeling of multi-strata forest fire severity using Landsat TM Data

Most of fire severity studies use field measures of composite burn index (CBI) to represent forest fire severity and fit the relationships between CBI and Landsat imagery derived differenced normalized burn ratio (dNBR) to predict and map fire severity at unsampled locations. However, less attention has been paid on the multi-strata forest fire severity, which represents fire activities and ecological responses at different forest layers. In this study, using field measured fire severity across five forest strata of dominant tree, intermediate-sized tree, shrub, herb, substrate layers, and the aggregated measure of CBI as response variables, we fit statistical models with predictors of Landsat TM bands, Landsat derived NBR or dNBR, image differencing, and image ratioing data. We model multi-strata forest fire in the historical recorded largest wildfire in California, the Big Sur Basin Complex fire. We explore the potential contributions of the post-fire Landsat bands, image differencing, image ratioing to fire severity modeling and compare with the widely used NBR and dNBR. Models using combinations of post-fire Landsat bands perform much better than NBR, dNBR, image differencing, and image ratioing. We predict and map multi-strata forest fire severity across the whole Big Sur fire areas, and find that the overall measure CBI is not optimal to represent multi-strata forest fire severity.     

Assessing mammal responses to perturbations in temperate aridlands of Argentina

Loss of species richness and reduced abundance have been the main responses to perturbations of small- and medium-sized mammals in arid and semi-arid areas. Nonetheless, some mammal species whose habitat requirements are met in disturbed patches may benefit from structural changes in the environment brought about by perturbations.In desert areas of Argentina different mammal responses are attributable to both a lower complexity of disturbed patches and a decrease in sheltered places. Therefore, species associated with high plant cover either decrease in number or become locally extinct at sites affected by fire or grazing, whereas species using open areas are favored by these events.The negative effects historically assigned to different disturbances may be mitigated by adopting a hierarchical approach that considers patch diversity in different successional stages as well as the multiple opportunities of patch occupation by mammal species.     

长白山天池火山——一座具潜在喷发危险的近代火山

通过对长白山天池火山近代喷发历史、喷发规模、喷发物类型的调查和研究,提出该火山是一座具潜在喷发危险的大型近代活动火山.建议开展对该火山的动态监测和系统研究.     

北京地区地质灾害成灾条件研究

地质灾害是由地质作用造成的对人类生命,生产活动.财产、资源环境危害的地质事件。其成灾条件包括自然条件和经济社会条件(人类活动)两方面。本文拟从自然条件的危险性和社会经济条件的易损性两方面研究北京地区的成灾风险,提出了地质灾害工作发展方向。     

危险理论与影像目标检测

探讨了危险理论与影像目标检测的内在联系,用危险理论解释了影像目标检测的整个过程,并提出了一种面向影像目标检测的危险模型。该模型将目标检测的过程视为一种生物免疫系统检测危险抗原的过程,其中兴趣目标被视为“危险抗原”,目标检测器被视为一种“抗原提呈细胞”。通过高分辨率遥感影像车辆目标检测实验,说明了危险理论在影像目标检测中应用的有效性和可行性。     

西南某水电站坝址区泥石流的运动特征及危险性分析

西南某水电站坝址区内分布有多条泥石流沟,泥石流对库区及建筑物的安全威胁较大。专项调查以DB沟为例,通过对泥石流的运动特征和泛滥危险性分析,根据得到的泥石流流速、流量、入库量及泥石流泛滥型分析数据,提出了综合治理的措施和建议,对水电站的安全施工和运行具有重大的指导意义。     

锦界煤矿水文地质特征与矿井充水危险性预测

矿井充水危险性预测是矿井水害防治的重要工作。通过锦界煤矿矿井水文地质特征的研究,总结了煤矿地下含(隔)水层的发育特征及其与煤层的4种空间组合关系。分析得出矿井的主要充水水源为直罗组风化基岩裂隙含水层,充水通道为煤层采后所产生的导水裂隙带,计算并实际验证了导水裂隙带发育高度。依据采动条件下隔水层隔水性的判据,预测圈定了3^-1煤层采后地表松散沙层与风化基岩含水层遭受破坏有可能发生充水的危险地段及充水危险性。     

火烧对湿地生态系统影响研究进展

火烧对湿地生态系统的影响是国内外火生态学和湿地生态系统研究中的一个热点。综述了国内外关于火烧对湿地生态系统各组成部分影响的研究进展,总结了湿地火烧的特点,火烧对湿地植物生长发育、群落特征的影响,火烧对土壤理化性质、对土壤中碳氮等元素形态及分布特征的影响。并针对目前湿地火烧在研究内容和方法上存在的问题,结合国外研究特点,提出了今后国内湿地火烧的研究展望。     

大地形变测量所反映的天山最新构造运动

新疆的新构造运动强烈,各大山系主体显示了断块抬升运动,而两大盆地则表现为相对下沉。分布在山系与盆地交接部位的大型活动断裂和强烈的地震活动有密切的联系。为了解新疆地壳形变的面貌,我们利用50年代至今30多年的精密水准测量资料,绘制了新疆垂直形变速率等值线图。图中清晰地反映了最新构造运动的形态,以及与地质构造的关系。南、北天山交汇的部位是北西向构造带与东西向构造带的汇合部,也是垂直形变速率等值线密度最大的地段。高速隆起与下降相伴生,今后10年内这里是大地震的潜在危险区。     

Load characteristics of steel and concrete tubular members under jet fire: An experimental and numerical study

The aim of this study was to evaluate the load characteristics of steel and concrete tubular members under jet fire, with the motivation to investigate the jet fire load characteristics in FPSO topsides. This paper is part of Phase II of the joint industry project on explosion and fire engineering of FPSOs (EFEF JIP) ( [Paik and Czujko, 2009] and [Paik, 2010]). To obtain reliable load values, jet fire tests were carried out in parallel with a numerical study. Computational fluid dynamics (CFD) simulation was used to set up an adiabatic wall boundary condition for the jet fire to model the heat transfer mechanism. A concrete tubular member was tested under the assumption that there is no conduction effect from jet fire. A steel tubular member was tested and considered to transfer heat through conduction, convection, and radiation. The temperature distribution, or heat load, was analyzed at specific locations on each type of member. ANSYS CFX, (2008) and KFX, 2007 codes were used to obtain similar fire action in the numerical and experimental methods. The results of this study will provide a useful database to determine design values related to jet fire.