鄱阳湖湿地植被退化原因分析及其预警

2003年以来,鄱阳湖长期处于低枯水位状态,湖盆植被面积减少600km2;洲滩土壤含水量降低,旱生植物物种入侵,占据高程15m以上洲滩,湿地植被演变成中生性草甸,使物种大幅度增加;湿生和水生植物向湖中心下移,生长空间缩减;对水深、污染物敏感的植物群落的物种、生物量减少,生物多样性退化;对水深适应性强和耐污染的植物迅速扩张。无序采砂、防火烧荒、牲畜放牧加剧了这一局面。在气候变化和人类活动影响下,鄱阳湖湿地植被正在逐步退化。为了遏制这一退化现象,正在建立鄱阳湖健康评价体系与标准,加强植物群落固定断面和针对稀有物种、对水深和污染物敏感物种、危害湖泊健康物种进行专项监测,针对发现的问题,用遥感影像辨识、实地勘测研究分析全湖变化状况,判断其危害程度,提出防治对策,向相关部门和地区提出预警建议。     

黄海绿潮灾害应急遥感监测和预测预警系统

黄海绿潮灾害应急遥感监测和预测预警系统是在绿潮应急遥感监测技术、应急快速漂移预测等技术研究的基础上,基于GIS技术构建了集绿潮遥感信息解译和提取、多源监测数据融合、快速漂移预测和预警产品制作和发布综合业务化平台。在应急遥感监测数据提取方面主要研发了信息提取准自动化技术和多源多时间窗的绿潮监测数据融合技术;在应急预测技术方面主要基于精细化大气和海洋环境动力场,研发了绿潮快速应急漂移预测模型,并通过海上和后报实验提高模拟精度。本系统服务于国家海洋局和政府防灾减灾应急部门,为海上运动、水产养殖、滨海旅游、交通运输、渔业生产等涉海活动和海洋管理提供了科学可靠的技术保障,特别在2008年奥运会帆船/板赛和2012年亚洲沙滩运动会的绿潮监测和预测预警保障工作中发挥了重要的作用,具有巨大的社会、经济和生态效益。     

粤北某矿横石河流域周围土壤重金属预测与生态风险预警评估

以粤北某矿横石河流域周围表层土壤2010年和2013年两批区域调查数据为基础,对其土壤中重金属含量变化趋势进行预测,并进行生态风险预警评估。结果显示,3年间土壤中Cd、Cu、Pb、Zn等元素含量降低明显,现累积速率分别为-0.001、2.88、3.71和3.11mg/(kg·a),相对累积速率以Cd最快,Zn、Cu、Pb次之;生态风险预警评估显示凉桥村和水楼下村的生态风险达到重警,上坝村为轻警。在无突变情景下,根据现累积速率预测了未来30年内的生态环境质量变化,并提出建议。     

灌区工程生态环境影响评价特点与展望

随着我国人口的增长及人民物质生活水平的不断提高,灌区工程作为粮食安全的重要保障,未来其建设步伐将不断向前迈进,而作为预防、治理生态破坏的基础,灌区工程开展生态环境影响评价的现实意义及作用将日益显著。本文介绍了大中型灌区工程主要生态环境影响,及灌区工程生态环境影响评价特点和重点,并对灌区工程生态环境影响评价进一步完善与发展进行了展望。     

儿童对不同形状字体警示语标识的眼动特征

为研究儿童对不同形状字体警示语标识的视觉注意特征,将字体形状为单一变量的警示语标识图片作为视觉刺激材料,利用Eye-Link Ⅱ型眼动仪记录了30名小学生观看这些图片时的注视点个数和首次注视时间等试验数据,用SPSS分析了注视点个数和首次注视时间,基于视觉注意理论结合主观调查问卷结果表明:1)被试者对黑体字体注意程度最大;2)儿童对不同形状字体警示语标识的注意程度由大到小为黑体、隶书、宋体(楷体)、幼圆.     

Driver Behavior During Overtaking Maneuvers from the 100-Car Naturalistic Driving Study

Objective: Lane changes with the intention to overtake the vehicle in front are especially challenging scenarios for forward collision warning (FCW) designs. These overtaking maneuvers can occur at high relative vehicle speeds and often involve no brake and/or turn signal application. Therefore, overtaking presents the potential of erroneously triggering the FCW. A better understanding of driver behavior during lane change events can improve designs of this human–machine interface and increase driver acceptance of FCW. The objective of this study was to aid FCW design by characterizing driver behavior during lane change events using naturalistic driving study data.

Methods: The analysis was based on data from the 100-Car Naturalistic Driving Study, collected by the Virginia Tech Transportation Institute. The 100-Car study contains approximately 1.2 million vehicle miles of driving and 43,000 h of data collected from 108 primary drivers. In order to identify overtaking maneuvers from a large sample of driving data, an algorithm to automatically identify overtaking events was developed. The lead vehicle and minimum time to collision (TTC) at the start of lane change events was identified using radar processing techniques developed in a previous study. The lane change identification algorithm was validated against video analysis, which manually identified 1,425 lane change events from approximately 126 full trips.

Results: Forty-five drivers with valid time series data were selected from the 100-Car study. From the sample of drivers, our algorithm identified 326,238 lane change events. A total of 90,639 lane change events were found to involve a closing lead vehicle. Lane change events were evenly distributed between left side and right side lane changes. The characterization of lane change frequency and minimum TTC was divided into 10 mph speed bins for vehicle travel speeds between 10 and 90 mph. For all lane change events with a closing lead vehicle, the results showed that drivers change lanes most frequently in the 40–50 mph speed range. Minimum TTC was found to increase with travel speed. The variability in minimum TTC between drivers also increased with travel speed.

Conclusions: This study developed and validated an algorithm to detect lane change events in the 100-Car Naturalistic Driving Study and characterized lane change events in the database. The characterization of driver behavior in lane change events showed that driver lane change frequency and minimum TTC vary with travel speed. The characterization of overtaking maneuvers from this study will aid in improving the overall effectiveness of FCW systems by providing active safety system designers with further understanding of driver action in overtaking maneuvers, thereby increasing system warning accuracy, reducing erroneous warnings, and improving driver acceptance.     

基于物联网技术的化工园区环境应急预警系统研究

为及时有效应对化工园区内各种突发性环境污染事故,采用物联网技术构建化工园区环境应急预警系统,主要包括重点区域太阳能无线自持子系统、远红外气体及火灾智能监测子系统、开路紫外差分吸声光谱气体监测子系统、管网次声波监测子系统和仪器、试剂及样品管理子系统5个子系统。该系统的运行可对整个园区及其周边的环境质量进行有效监控,预防和及时控制各种环境污染事故的发生,同时为园区管理部门提供数据和信息支持。     

数据缺失条件下基于MLP神经网络的水华风险预警方法研究

针对水华风险预警过程中相关监测指标数据缺失的问题,借鉴多元统计和随机分析构建了一种缺失数据插补方法,用于弥补现场调查数据的不足.基于主成分分析,对水华相关影响指标进行降维,确定水体水华风险预警模型的输入层变量.同时,采用多层感知器(MLP)人工神经网络模型对水华表征指标叶绿素a的浓度进行预测,并引入风险概率的概念,提出了水华风险概率计算公式,完善了水华预警的风险表达.最后以三峡库区典型支流大宁河为案例的研究证明了上述方法的可操作性.研究结果显示,插补数据条件下和未插补数据条件下的大宁河水华风险预警模型决定系数分别为0.9711和0.7769,前者的模型准确性更高,叶绿素a浓度预测效果更好;预测时段内大宁河11 d为水华蓝色预警(无警)级别,水华发生的风险概率为1.99%~18.61%;1 d达到水华橙色预警(中警)级别,水华发生概率为90.48%.     

How changing fire management policies affect fire seasonality and livelihoods

There is a long history of fire management in African savannas, but knowledge of historical and current use of fire is scarce in savanna-woodland biomes. This study explores past and present fire management practices and perceptions of the Khwe (former hunter-gatherers) and Mbukushu (agropastoralists) communities as well as government and non-government stakeholders in Bwabwata National Park in north-east Namibia. Semi-structured interviews and focus groups were used in combination with satellite data (from 2000 to 2015), to investigate historical and current fire management dynamics. Results show that political dynamics in the region disrupted traditional fire practices, specifically a policy of fire suppression was initiated by colonial governments in 1888 and maintained during independence until 2005. Both the Khwe and Mbukushu communities use early season (i.e. between April and July) fires for diverse interrelated historical and current livelihood activities, and park management for managing late season fires. The Mbukushu community also use late season burns to prepare land for crops. In this study, we use a pyrogeographic framework to understand the human dimension of fires. This study reveals how today’s fire management practices and policies, specifically the resurgence of early season burning are entrenched in the past. Understanding and acknowledging the social and cultural dynamics of fire, alongside participatory stakeholder engagement is critical for managing fires in the future.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01351-7) contains supplementary material, which is available to authorized users.     

长输油气管线安全生产事故监测预警平台设计与实现

阐述了适用于长输油气管线安全生产事故应急救援全过程的事故监测预警平台的整体结构和实现要点,主要从长输油气管线的工作运行和事故特点出发,结合安全生产事故应急救援过程中各环节的业务需求,提出监测预警平台的建设目标和适用范围,对平台的需求进行分析,并进一步对平台的构建思路进行讨论。其中重点从应急预防、应急准备、应急响应和应急恢复四个阶段的应急任务和需求入手,提炼出长输油气管线安全生产事故监测预警平台在＂后端应急指挥中心＂、＂现场应急指挥中心＂及＂移动指挥所＂等多个位置和场景下的建设目标和功能框架,并对平台设计与实现过程中可能涉及到的平台总体结构设计、平台软硬件及网络支撑环境、平台数据采集传输与共享模式等方面进行了简要描述。