遥感监测土壤湿度综述

遥感技术具有大面积同步观测,时效性、经济性强等特点,为大面积动态监测土壤湿度提供了可能。本文对近年来国内外遥感监测土壤湿度的理论、方法的发展和应用进行了回顾,重点介绍了目前已经比较成熟和广泛应用的基于可见光与热红外波段的植被指数方法以及在干旱、半干旱地区的应用,通过对比分析了各种遥感监测方法的优缺点,指出了土壤湿度遥感监测方法存在的不足,展望了土壤湿度遥感监测方法的发展趋势。     

基于RS和GIS的生态环境状况时空变化研究--以河南省为例

生态环境状况评价是资源合理利用、制定社会经济发展规划及生态环境保护对策的重要依据。现以河南省行政区为研究区域,基于遥感影像、水资源及环境统计数据,采用生态环境状况指数(EI)和空间格局分析方法,综合对比分析河南省2014—2018年生态环境状况时空变化及其冷热点空间分布。研究结果表明:(1)2014—2018年河南省EI值变化范围为60.6~63.5,生态环境状况整体呈现稳中趋好态势,除开封市和济源市外,16个省辖市的EI值均有所增加,位于西部山区丘陵地带的三门峡、洛阳和平顶山市EI值增加明显。(2)2014—2018年河南省生态环境的G*i指数的高值区域位于西部地区的三门峡市和洛阳市,且5年内没有发生变化,较为稳定。G*i指数的高、低值区域与EI值的高值和低值区表现出较高的一致性。     

A pilot project to detect and forecast harmful algal blooms in the northern Gulf of Mexico

More timely access to data and information on the initiation, evolution and effects of harmful algal blooms can reduce adverse impacts on valued natural resources and human health. To achieve this in the northern Gulf of Mexico, a pilot project was initiated to develop a user-driven, end-to-end (measurements to applications) observing system. A key strategy of the project is to coordinate existing state, federal and academic programs at an unprecedented level of collaboration and partnership. Resource managers charged with protection of public health and aquatic resources require immediate notice of algal events and a forecast of when, where and what adverse effects will likely occur. Further, managers require integrated analyses and interpretations, rather than raw data, to make effective decisions. Consequently, a functional observing system must collect and transform diverse measurements into usable forecasts. Data needed to support development of forecasts will include such properties as sea surface temperature, winds, currents and waves; precipitation and freshwater flows with related discharges of sediment and nutrients; salinity, dissolved oxygen, and chlorophyll concentrations (in vivo fluorescence); and remotely-sensed spatial images of sea surface chlorophyll concentrations. These data will be provided via a mixture of discrete and autonomous in situ sensing with near real-time data telemetry, and remote sensing from space (SeaWiFS), aircraft (hyperspectral imagery) or land (high-frequency radar). With calibration across these platforms, the project will ultimately provide a 4-dimensional visualization of harmful algae events in a time frame suitable to resource managers.     

Plant Phenology in Western Canada: Trends and Links to the View From Space

One feature of climate change is the trends to earlier spring onset in many north temperate areas of the world. The timing of spring flowering and leafing of perennial plants is largely controlled by temperature accumulation; both temperature and phenological records illustrate changes in recent decades. Phenology studies date back over a century, with extensive databases existing for western Canada. Earlier spring flowering has been noted for many woody plants, with larger trends seen for species that develop at spring's start. Implications for ecosystems of trends to earlier spring arrival include changes in plant species composition, changes in timing and distribution of pests and disease, and potentially disrupted ecological interactions. While Alberta has extensive phenology databases (for species, years, and geographic coverage) for recent decades, these data cannot provide continuous ground coverage. There is great potential for phenological data to provide ground validation for satellite imagery interpretation, especially as new remote sensors are becoming available. Phenological networks are experiencing a resurgence of interest in Canada (www.plantwatch.ca) and globally, and linking these ground-based observations with the view from space will greatly enhance our capacity to track the biotic response to climate changes.     

大气污染物排放调查监测研究进展

系统总结了当前大气污染物排放调查监测的主要方法及其在全球、区域、局地等不同尺度的典型应用,分析了地面监测、模型模拟与遥感反演3种方法受排放源多样、成分复杂、时空变异显著等因素影响,在尺度效应、成分解析等方面存在的问题。从优化监测方法、改进监测模式、融合监测技术等角度,提出了构建现代化大气污染物排放调查监测网络、开展污染物在不同排放阶段的变化解析研究及在不同圈层间的迁移全过程研究等建议。     

湄洲湾沿海能见度和大气烟尘污染的变化

利用1985～2004年能见度和有烟日观测资料,统计分析了20 a当中,湄洲湾沿海能见度和大气受烟尘污染的变化.结果表明:湄洲湾夏季沿海能见度明显好于冬季,这可能与冬夏盛行风向不同,输送排放污染源地不同以及不同季节天气气候条件相关.湄洲湾冬季和夏季沿海能见度呈显著下降趋势,尤以夏季为突出.污染日在86～199d之间徘徊;1985～1988年是污染"轻微期",年平均污染日101d;1997～2000年是污染"严重期",年平均污染日达186 d.     

网络化SCADA系统安全防御策略

SCADA系统在电力、给水、石油、化工等领域的数据采集与监视控制以及过程控制等诸多领域应用广泛。一直以来,很多工程师和管理者认为SCADA系统是一个相对孤立的物理隔离的系统,有着强有力的访问控制,是相对安全的。然而,随着网络技术和通信技术和计算机技术的发展,SCADA系统逐渐发展成开放式透明运作的标准系统,由此造成系统的安全性降低。针对当前的开放式SCADA系统,本文介绍了系统构成和系统的网络化结构特点,分析了系统可能存在的安全隐患并提出一种层次结构的＂防御圈＂安全策略。该策略从企业网络和SCADA网络两方面实施具体的安全防护措施。通过对＂防御圈＂中各个层的合理配置,可以有效地保障SCADA系统安全。     

南通市生态环境遥感监测及其动态变化研究

应用遥感技术对南通市生态环境进行监测,利用GIS技术对遥感监测结果进行解译与分析,同时对2006-2009年南通市生态环境时空动态变化进行了分析与评价.结果表明,南通市生态环境类型以耕地、水域和城乡、工矿、居民用地为主,未利用土地面积极小.其生态环境动态变化的主要特点是耕地面积普遍有小幅度减少,以城镇建设用地为主的城乡、工矿、居民用地增加较多,林地面积无明显变化;未利用土地面积有所减少,以盐碱地面积减少为主,减少的面积主要用于耕地和建设用地.     

应用遥感技术监测和评价太湖水质状况

利用遥感信息和有限的实地监测数据建立了太湖水质参数预测模型 ,该方法可以用于太湖水质污染的预测、分析和评价 ,能够较好地反映水质的空间分布特征 ,尤其适合于大范围水域的快速监测 .研究结果表明 ,利用单波段、多波段因子组合以及主成分分析等手段可以使遥感信息得到更充分的利用 ,从而使预测结果更加精确 .预测结果显示 ,太湖流域已经呈现了严重的富营养化趋势 ,且空间分布不均衡 .东太湖以及靠近无锡和苏州的湖体附近相对污染更为严重 .     

氯代有机物的生物处理前景

综述氯代有机物的结构与其生物降解性的关系。降解机理和所需环境条件，以及利用现代基因工程技术提高控制氯代有机物污染能力的可行性；研究的热点领域有：共基质条件，厌氧－好氧联合处理系统，构建跗工程菌株，化学、物理和生物联合处理工艺和反应器设备等；表明利用生物技术控制氯代有机物污染的应用前景是光明的。