Charcoal morphotypes in lake sediments from British Columbia (Canada): an assessment of their utility for the reconstruction of past fire and precipitation

Quantitative analysis of variations in morphological types of charcoal were undertaken in sediment cores from three lakes on the Interior Plateau (BC, Canada) over the period AD 1919–2000. Seven distinct morphological types of charcoal were identified based on particle shape and structural features and were compared with seasonal precipitation and recorded area burned within 20 km-radius of study lakes. Fragile-type charcoal fragments, termed type M, displayed significant relationships to recorded area burned in sediment cores from Prosser (r ² = 0.5; p = 0.0001) and Opatcho (r ² = 0.2; p = 0.02) lakes. However, nonsignificant correlations (p > 0.05) were found between total charcoal and area burned. Robust and highly elongated morphotypes C and F were correlated to recorded spring precipitation (r ² = 0.5; p = 0.002) in Opatcho Lake. Charcoal from a sediment core from Big Lake, the lake with the largest watershed, was significantly but inversely related to past fires (r ² = 0.44; p = 0.0003), suggesting important contributions from secondary transportation and deposition. Models were developed to infer relative area burned and precipitation for the study lakes. Our results suggest that charcoal morphotypes are related to the biogeoclimatic and lake watershed characteristics. This study also suggest that charcoal morphotypes can provide insights on past fire and climate, which was not possible based on traditional analysis of total charcoal.     

The Northridge, California, earthquake of 1994: fire ignition by strong shaking

The Northridge earthquake contributed unprecedented detail and quality of data on strong ground motion and on its effects on man-made structures. About 110 fires have been attributed directly to the effects of this earthquake. Two hypotheses for the principal causative agents leading to fire ignition were examined: differential motion and strains in the soil, and inertial forces. The fire-ignition frequency is described with respect to: (1) simple measures of strain in the soil (via density of water pipe breaks, n), (2) occurrence of severely damaged buildings (via density of red-tagged buildings, N), (3) site intensity of shaking, (I_MM), and (4) inertial forces (via peak horizontal ground velocity, v_m). It is shown that the rate of fires (per unit area) ignited by earthquake shaking can be predicted by several empirical equations of comparable accuracy and in terms of common scaling parameters of strong ground motion.     

森林防火监测站选址及可视域分析

火灾是森林的宿敌,危害巨大。建立监测站不仅是一种有效的森林防火措施,还是我国主流的预防对策。文章基于GIS对某林区数字高程模型进行空间分析,通过分区查询统计理论提取其最高点,利用缓冲区技术去除不合理高程点,获取可视域范围较大的监测站点分布图;根据泰森多边形对监测站点监测区域进行可视域分析,获取其可视域分析指标值,同时剔除功能重复的站点,以得到其较为理想的分布。该方法只需单一的数字高程模型数据,选取站点过程考虑综合因素,可操作性强,为森林防火监测站的部署和分析提供了一种科学参考。     

基于NewMap Server的森林防火应急指挥系统设计与实现

综合运用3S技术,以NewMap Server为地理信息系统开发平台,建立森林防火应急指挥系统,具体介绍了系统设计思想,系统结构和系统开发。并结合济源市森林防火应急指挥系统实例,介绍了预报监测、辅助决策、、扑救指挥和灾后评估等系统功能。     

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.     

消防战评三维辅助系统应用研究

随着"科技兴防"战略与"智慧城市"发展的深度融合,"智慧消防"的提出与实施,原有基于文字部分、图表部分的战评手段已不能满足现代消防战评的需求。本文在介绍消防战评建设的基础上,阐述了三维消防战评辅助系统的结构与创新点,并详细描述了系统中主要功能的设计思想与实现方法,最终结合案例简述了系统的应用。     

Spatial Characteristics of Regional Wildfire Frequencies in Intermountain West Grass-Dominated Communities

Understanding the environmental factors that influence spatial patterns of rangeland wildfires facilitates both fire and land management decisions. I used discriminant analysis to examine ignition frequency of lightning-initiated fires in grass-dominated communities in the Intermountain West between 1980 and 1994, then mapped regional fire frequencies to illustrate spatial patterns. Two canonical discriminant functions effectively separate groups of high, medium, and low ignition frequencies, based on climate conditions and fuel characteristics. Regions of highest frequency tend to have large elevational differences, more mesic climates, and less annual grass cover. Spatial patterns of ignition frequencies tend to reflect local topography, with higher frequencies west of 119° W. Expansion of exotic annual grasses throughout the region may be reducing differences in ignition frequency between regions of highest and lowest frequency.     

Facilitating Public Involvement in Strategic Planning for Wildland Fire Management∗

Wildland fire creates a complex relationship between federal agencies and public stakeholders. Questions surrounding the public's role in federal wildland fire management point to broader questions about the relationships among scientists, policymakers, federal agencies, and the public. In this article we report on a project to provide information about the key components of federal policies that govern wildland fire management. The goal is to enhance the decision support capabilities of a geographic information system (GIS)-based fire risk model and the capacity of users to interpret the outputs of the model from a fire policy perspective. We conclude by making recommendations for how this and other such tools might be refined to improve and expand policy interactions among government land and resource management agencies, scientists, and the public.     

基于土壤水分和气象要素的林火预报研究——以广东省为例

基于国内现行的森林火险气象指数和单因子火险贡献度模型,以及逻辑回归模型和随机森林模型,在林火预报中引入微波遥感土壤水分信息,使用MCD14DL火点数据集和地面气象观测资料对广东省不同时间尺度的林火发生概率进行预测。结果表明：逻辑回归模型和随机森林模型构建的林火预测模型显著优于现行的森林火险气象指数和单因子火险贡献度模型,预测精度提升约20%。其中,随机森林模型对林火频数的解释程度最高（两者相关系数为0.476）。此外,加入微波土壤水分信息后,相较原有的基于气象要素的林火预测模型,2种机器学习模型的预测精度均略有提升,体现了表层土壤水分信息在林火预报中的重要性。研究可为高效提取对地观测信息,以改进华南地区不同时间尺度的林火预报工作提供参考。     

Forest fire effects on groundwater in a coastal aquifer (Ravenna,Italy)

We examined the fire‐induced changes in groundwater recharge rate. This aspect is particularly important in the case of large forested areas growing over a coastal aquifer affected by saltwater intrusion. In the Ravenna coastal area (Italy), pine forests grow on coastal dune belts, overlying a sandy unconfined aquifer, which is strongly affected by marine ingression. Three groundwater profiles across the forest and perpendicular to the coastline were monitored for groundwater level, physical, and chemical parameters. The aims were to define groundwater quality, recharge rate, freshwater volume, and highlight change, which occurred after a forest fire with reference to pre‐fire conditions. Analytical solutions based on Darcy Law and the Dupuit Equation were applied to calculate unconfined flow and compare recharge rates among the profiles. The estimated recharge rates increased in the partially and completely burnt areas (219 and 511 mm year^?1, respectively) compared with the pristine pine forest area (73 mm year^?1). Although pre‐fire conditions were similar in all monitored profiles, a post‐fire decrease in salinity was observed across the burnt forest, along with an increase in infiltration and freshwater lens thickness. This was attributed to decrease canopy interception and evapotranspiration caused by vegetation absence after the fire. This research provided an example of positive forest fire feedback on the quantity and quality of fresh groundwater resources in a lowland coastal aquifer affected by saltwater intrusion, with limited availability of freshwater resources. The fire provided an opportunity to evaluate a new forest management approach and consider the restoration and promotion of native dune herbaceous vegetation.