煤田火区环境影响综合评价指标体系与评价方法

在研究煤田火区对自然-社会经济系统影响的基础上,提出了煤田火区环境影响综合评价指标体系的构建思路,建立了煤田火区环境影响评价的一般性指标体系,包括5级32个指标。以内蒙古乌达煤田火区为实例,论述了煤火环境影响综合评价的实施过程。根据煤田火区特征,在一般指标体系框架内确定了23个评价指标,采用层次分析法与综合指数法相结合,建立了火区环境影响综合评价公式。评价结果表明,乌达煤田火区对环境的影响为较严重水平,与定性分析结果相符。     

煤矿开采对毕节地区地下水环境的影响研究

在对毕节地区煤矿开采现状调查的基础上,探讨煤炭开采对地下水环境的影响,分别从水资源量减少、水质污染、含水层水位变化三个方面进行论述,并指出由此引发的相关的问题,最后提出了煤矿开采区保护水环境、防止水环境恶化的建议。     

Forest Fire Alert System: a Geo Web GIS prioritization model considering land susceptibility and hotspots – a case study in the Carajás National Forest,Brazilian Amazon

To increase the monitoring potential of forest fires, an alert classification methodology using satellite-mapped hotspots has been established to help forest managers in the prioritization of which hotspot to be verified in the field, thus potentially improving the distribution of fire-fighting resources. A computer application was developed based on web-distributed geographical information technology whose main function is to interact automatically generated satellite hotspots and risk areas indicated in fire-susceptibility maps and classify them into five alert levels. The location of the hotspots is available continuously every 4 h, and a susceptibility map is produced daily through map algebra algorithm, which uses static (topography, vegetation and land use) and dynamic (weather) variables. Every process runs through automated geoprocessing routines. The methodology was tested during the dry period of 2007 in the Carajás National Forest, in the Brazilian Amazon, within an area of 400,000 ha. It is a critical area constantly threatened by fires caused by invasions and deforestation owing to intense agribusiness advances and mining activities in its surroundings. This situation results in observations of many hotspots inside the study area for the same day and almost the same time period, in places of extreme opposites, demanding complex rapid analysis and hindering the decision of the displacement of fire-fighting teams. Further, a major mining company operates within the National Forest area, maintaining actions of protection as part of its environmental mining license. Results are presented under three aspects: (i) the credibility of the daily susceptibility map (algorithm), which showed strong correlation between areas of greatest risks and the confirmed forest fires; (ii) the reliability of hotspots (alert levels), confirming 71% of fires; (iii) accuracy in the decision of which hotspot to be checked, which revealed the same number of verifications at different alert levels, 82% confirmed alert 5 hotspots (maximum) and only 50% from alert 1 (minimum), resulting in faster fire-fighting actions, minimizing burned areas and, in some cases, allowing fire control before its spreading. Therefore, the methodology demonstrated that GIS routines are able to determine the relationship between a reality-based, interpreted susceptibility map of the area and satellite-generated hotspots, highlighting the ones of highest hazard level through the alert classification, becoming an important tool to help decisions from the fire-control center, especially for high-risk regions. The methodology may be extrapolated to other forested areas.     

国产高分系列卫星在森林火灾应急处置中的全流程应用——以四川九龙县三岩龙乡“4·08”森林火灾为例

四川西部高山峡谷地貌发育,山高林密且地质环境恶劣,区内林草资源丰富,森林火灾多发、易发、频发,灾害应急处置难度大,防控任务重。国产高分系列卫星影像具有时空分辨率高、载荷类型多、机动性强、幅宽范围大、成像迅速等优点,对川西地区森林防灭火、灾害应急处置及防灾减灾等有明显优势。以2021年四川九龙县三岩龙乡“4·08”森林火灾为例,利用国产高分系列卫星数据分别对森林火灾初期、中期及晚期开展应急处置,包括快速解译林火火灾救援要素(初期)、感知亮温异常态势(中期)、跟踪监测过火区动态(中期)、结合火场需求提供应急扑救部署建议(中期)、开展灾损解译评估(晚期)及火后泥石流易发性评价(火后)等,结果表明国产高分系列卫星对森林火灾应急处置的全流程应用具有实践指导意义。     

南瓮河湿地森林火灾预防管理对策分析

针对南瓮河湿地森林火灾发生的特点,科学分析了南瓮河湿地森林火灾影响因素,在总结多年森林防火工作经验的基础上,提出森林防火必须准确把握火灾发生规律,不断提高火灾防范能力,建立健全防火长效治本机制,从根本上减少或避免特大森林火灾发生。     

基于ArcEngine的次生火灾蔓延模拟及评估系统

次生火灾对人类的危害极大。分析次生火灾的产生原因,研究次生火灾的起火点预测模型、火灾蔓延影响因素和蔓延模型、影响评估模型。基于ArcEngine组件开发了次生火灾蔓延模拟及评估系统分析评估系统。该系统可以模拟单个或多个起火点的动态蔓延和分析评估次生火灾对人类生命财产造成的损失。     

Disintegration of Fan Sediments in Death Valley,California, by Salt Weathering

In Death Valley, California, an area of high aridity and great salinity, alluvial fans de scend into the zone of salt accumulation. When the rounded fan gravels come into contact with salt, some of which is sodium sulfate, they are rapidly shattered and reduced in size. Silt and clay are formed by this salt weathering process and this fine material may be subject to deflation processes.     

A COMPARISON OF HYDROLOGY AND VEGETATION BETWEEN A CHANNELIZED STREAM AND A NONCHANNELIZED STREAM IN WESTERN TENNESSEE

The purpose of this study was to provide baseline data on floodplain forest structure, composition, and function that would be needed to predict and monitor the consequences of a proposed stream restoration project. This project would involve the “dechannelization” of Stokes Creek, a stream in western Tennessee that was channelized and leveed in the first half of the 1900s. To this end, we collected data on surface hydrology, soil redox potential (Eh), and the structure and composition of the floodplain vegetation of Stokes Creek. To place our findings into a regional context, we also collected comparable vegetation data from plots located along a nonchannelized stream reach of the Wolf River near Moscow, Tennessee. While hydrologic fluctuations of floodplain sites were synchronous with river dynamics for the Wolf River, the hydrology of floodplain sites at Stokes Creek was constrained by the influence of beaver dams, backflooding, and ponding of overland flow behind levees. Consequently, composition of the forest overstory, understory, and herbaceous strata was significantly different between the two sites. For example, Stokes Creek had a noticeable lack of cypress and tupelo sites, and a greater abundance of red maple. Analyses of size-class structure and woody debris quantity reinforced the existing differences between the more natural and human-impacted systems. While the current hydrology apparently has a negative affect on bottomland hardwoods, scattered regeneration stems and soil redox measurements indicate that a dechannelization effort that yielded lower water tables in the Stokes Creek floodplain potentially could increase bottomland hardwood establishment. [Key words: channelization, western Tennessee, bottomland hardwoods, hydrology.]     

Effects of Disturbance Frequency on Canopy Age Structure and Species Composition in a Managed Midwestern Oak Savanna

In the Midwest, the oak savanna is a unique plant community located between the western prairies and northern forests, but, once the most common plant community in Wisconsin, it is now one of the region's rarest plant communities. To assess the success of varying intensities of management practices, standard dendrochronology and vegetation surveying methods were used to determine the age structure and species composition in oak savanna sites that varied from intensely managed to unmanaged. Size and age distributions revealed that the number of distinct cohorts of oaks increased in less managed sites. Seedlings and saplings were present in high frequencies in all sites; however, management practices such as fire applications that were too frequent apparently decreased oak survivorship, as did the competition in the closed canopies of the unmanaged sites. A fire frequency of 2-3 years eliminates competition, but a frequency of 4-6 years, typical of fire-adapted forest communities, allows for slower-growing species and younger oaks to survive, while still maintaining a low density. In these conditions, where growth rates vary in time, the use of dendrochronology is necessary to obtain an accurate canopy structure for fire-adapted forest communities. Quercus macrocarpa was dominant in the more managed sites, but shade-tolerant species were dominant in the unmanaged site. At present, the canopy composition in the managed sites represented an oak savanna assemblage; however, the unmanaged composition was shifting to a woodland assemblage. Thus, remnant oak savanna can be over- or under-managed, and unmanaged oak savanna can be overlooked as woodlands.     

基于GIS位置分配的城市消防站点优化布局探析

介绍了GIS"位置分配"基本原理和优化模型,基于地形图构建路网模型,应用最小化设施点数和最大化覆盖范围模型确定布局方案,划定管理服务区优化消防站选址。通过对消防站可达性及消防出行机动能力分析,找出消防站布局规律,为城市消防站布局规划提供参考。