Mapping lightning/human-caused wildfires occurrence under ignition point location uncertainty

Fire managers need to study fire history in terms of occurrence in order to understand and model the spatial distribution of the causes of ignition. Fire atlases are useful open sources of information, recording each single fire event by means of its geographical position. In such cases the fire event is considered as point-based, rather than area-based data, completely losing its surface nature. Thus, an accurate method is needed to estimate continuous density surfaces from ignition points where location is affected by a certain degree of uncertainty. Recently, the fire scientific community has focused its attention on the kernel density interpolation technique in order to convert point-based data into continuous surface or surface-data. The kernel density technique needs a priori setting of smoothing parameters, such as the bandwidth size. Up to now, the bandwidth size was often based on subjective choices still needing expert knowledge, eventually supported by empirical decisions, thus leading to serious uncertainties. Nonetheless, a geostatistical model able to describe the point concentration and consequently the clustering degree is required. This paper tries to solve such issues by implementing the kernel density adaptive mode. Lightning/human-caused fires occurrence was investigated in the region of Aragón's autonomy over 19 years (1983–2001) using 3428 and 4195 ignition points respectively for the two causes of fire origin. An analytical calibration procedure was implemented to select the most reliable density surfaces to reduce under/over-density estimation, overcoming the current drawbacks to define it by visual inspection or personal interpretation. Besides, ignition point location uncertainty was investigated to check the sensitivity of the proposed model. The different concentration degree and the dissimilar spatial pattern of the two datasets, allow testing the proposed calibration methodology under several conditions. After having discovered the slight sensitivity of the model to the exact point position, the obtained density surfaces for the two causes were combined to discover hotspot areas and spatial patterns of the two causes. Evident differences in spatial location of the origin causes were noted and described. The general trend follows the geographical features and the human activity of the study areas. The proposed technique should be promising to support decision-making in wildfire prevention actions, because of the occurrence map can be used as a response variable in fire risk predicting models.     

An innovative three-dimensional approach for the simulation of pressure vessels exposed to fire

The present study introduces an innovative approach to the detailed simulation of the pressure build-up in equipment containing saturated liquids when exposed to fire. The approach is based on the adoption of a fully three-dimensional (3D) computational fluid dynamics (CFD) model of the inner fluid. Experimental data gathered from literature studies were used to validate the model considering vessels of several scales and geometries exposed to a full engulfing pool fire. The comparison between the results of the 3D CFD model developed and those of two-dimensional (2D) literature models was also carried out. This enabled deriving precise indications on the selection of the most suitable approach based on the type of accidental scenario to reproduce, confirming 2D models as sound and reliable tools to model the fluid behaviour when homogeneous heat exposure conditions are present. On the other side, limitations of 2D approaches in capturing edge effects on i) temperature profiles, ii) recirculation patterns, and iii) energy accumulation in the vessel lading during fire exposure were identified and discussed. The results obtained represent a valuable source of information to support risk management and emergency response planning.     

火灾定量预测方法研究

应用预测学原理，对火灾定量预测方法进行了探讨，建立了一套适应不同火灾历史统计特点的平滑预测模型：滑动平均预测模型和指数平滑预测模型；考虑火灾事故的季节性变化，建立了季节性平滑预测模型。应用二重指数平滑预测模型和季节性平滑预测模型，对荆州地区１９９３￣１９９４年的火灾统计资料进行分析和预测，结果表明该地区今后的火灾发生呈上升趋势，提请有关部门注意防火安全。     

城市火灾危险性分析

本文提出了一个城市火灾危险性分析的一般模型。通过对实际火灾案例的统计分析，提出了火灾发生率的主导统计参数。并提出以超越概率曲线的方法来表达火灾危险性分析的结果。经验证，该模型具有可操作性，结论可信。     

火灾事故危险源辩识、评价及控制

运用系统安全工程方法对火灾事故危险源的辩识、评价及控制进行分析，提出火灾事故危险源辩识、评价及控制的方法。     

Effects of off-road vehicles on coastal foredunes at Fire Island,New York,USA

The effects of off-road vehicles (ORVs) on the dune system of Fire Island National Seashore, New York, USA, were examined through a detailed, two-year field study. The experimental approach was adopted in order to evaluate the environmental effects of ORVs in this zone. Adjacent control and impact sites were established in two locations. Vehicle impacts were applied at the equivalent rate of one vehicle pass per week. Monitoring of foredune vegetation through sequential quadrat surveys and construction of sea-ward limit maps showed a significant loss of vegetation resulting from ORV impacting. Loss of vegetation resulted in an alteration of the natural foredune profile, which could increase dune erosion during storm wave attack.     

Ecological planning proposal for Kruger National Park

This article discusses an application of the ecological planning model proposed by Van Riet and Cooks. The various steps outlined in this model have been applied to Kruger National Park in South Africa. The natural features of Kruger National Park, which form the basis of such an ecological planning exercise and from which the various land use categories, values, and zoning classes can be determined, are discussed in detail. The suitability of each of the various features is analyzed and a final zoning proposal for Kruger National Park is suggested. Furthermore a method for selecting a site for a new camp is illustrated by referring to the site for the new Mopane rest camp which is now under construction in the Kruger National Park. The conclusion is reached that the proposed ecological planning model can be used successfully in planning conservation areas such as Kruger National Park and for the selection of the most desirable sites for the establishment of new rest camps. Its suitability as a practical model in such planning exercises is proven by the fact that the siting proposals of two new camps based on this model have been accepted by the National Parks Board, the controlling body of Kruger National Park.     

Analysis and application of forest fuels data

Recent advances in fire modeling permit quantitative estimations of fire behavior from quantitative inputs that describe the fuel array and conditions, such as weather and site data, under which it will burn. This paper describes the collection, analysis, and stratification of flammable forest fuels data for coniferous forest ecosystems in Montana and then illustrates the resource management application of these data in three areas: the development of the fire behavior model, a determination of the model's sensitivity to input errors as reflected by fire behavior prediction errors, and the development of a fire hazard simulator (TAROT). A new integrated stand simulator, GANDALF, is highlighted.Conclusions center on the need to integrate fire management into the land management planning decision-making process.This work was supported by a USDI National Park Service contract to Gradient Modeling, Inc., a nonprofit research foundation devoted to ecologic research and resource management applications, and by cooperative aid agreements between Gradient Modeling, Inc. and the USDA Forest Service, Intermountain Forest and Range Experiment Station, Northern Forest Fire Laboratory (Fire in Multiple Use Management, R, D, and A Program).     

基于图像的火焰锋面法向速度场测量研究

火焰锋面是火焰的重要组成部分,反映了火焰的燃烧特性。针对传统方法测量火焰锋面速度场分辨率较低的问题,提出来了基于图像法测量火焰锋面法向速度场的方法。使用高速相机拍摄了多帧连续图像,提取火焰锋面,通过最小二乘法拟合锋面的切线,从而计算出每个点的法向速度,并进一步分析了火焰振荡的性质。实验表明该方法能够有效测量双瓦楞纸板产生的火焰在不同时刻的速度场,具有高分辨率、全场测量的特点,为其进一步推广提供了实验基础。     

某型飞机APU舱灭火系统设计

旨在设计某型飞机的APU舱灭火系统。通过对已有机型的分析和适航条款的解读,对灭火系统的安装方式和灭火瓶的安装位置进行了研究,计算了所需的灭火剂剂量,使用FLUENT仿真软件模拟了灭火喷嘴的位置和灭火剂喷射效果,为灭火系统的布局和优化提供参考。