水质关键因素光谱遥感监测技术分析

针对传统水体水质分析方法过度依赖于实地测量和实验室化学分析,需要耗费大量人力物力且效率不高的问题,从水质遥感监测数据获取手段、典型反演监测模型、不同水体光谱遥感监测应用状况、水质遥感监测技术应用及前景等方面分析归纳了使用遥感技术监测水质的新方法。从可用数据类型、数据特征等方面对水质遥感监测数据获取的3种主要手段进行了比较;从复杂程度、使用场景、优缺点等方面对4种典型的反演模型进行了归纳;对遥感数据和模型在Ⅰ类和Ⅱ类水体应用中的常用组合方式进行了分析总结。     

An open source GIS‐based Planning Support System: Application to the land use plan of La Troncal,Ecuador

Planning Support Systems (PSS) comprise a wide variety of geo‐technological tools related to GIS and spatial modeling aimed at addressing land planning processes. This article describes the OpenRules system, a PSS based on a previous system called RULES. Among OpenRules new features are its architecture, based exclusively on free and open source software, and its applicability to all land use types, including rural and urban uses. In addition, OpenRules incorporates an unlimited number of land evaluation factors and a new objective in land use spatial allocation. OpenRules has been programmed in Java and implemented as a module of the free GIS software gvSIG, with full integration between the GIS and the decision support tools. Decision support tools include multicriteria evaluation, multiobjective linear programming and heuristic techniques, which support three basic stages of land use planning processes, namely land suitability evaluation, land use area optimization and land use spatial allocation. The application of OpenRules to the region of La Troncal, Ecuador, demonstrates its capability to generate alternative and coherent solutions through a scientific and justified procedure at low cost in terms of time and resources.     

Reactive transport impacts on recovered freshwater quality during multiple partially penetrating wells (MPPW-)ASR in a brackish heterogeneous aquifer

The use of multiple partially penetrating wells (MPPW) during aquifer storage and recovery (ASR) in brackish aquifers can significantly improve the recovery efficiency (RE) of unmixed injected water. The water quality changes by reactive transport processes in a field MPPW-ASR system and their impact on RE were analyzed. The oxic freshwater injected in the deepest of four wells was continuously enriched with sodium (Na⁺) and other dominant cations from the brackish groundwater due to cation exchange by repeating cycles of ‘freshening’. During recovery periods, the breakthrough of Na⁺ was retarded in the deeper and central parts of the aquifer by ‘salinization’. Cation exchange can therefore either increase or decrease the RE of MPPW-ASR compared to the RE based on conservative Cl⁻, depending on the maximum limits set for Na⁺, the aquifer’s cation exchange capacity, and the native groundwater and injected water composition. Dissolution of Fe and Mn-containing carbonates was stimulated by acidifying oxidation reactions, involving adsorbed Fe²⁺ and Mn²⁺ and pyrite in the pyrite-rich deeper aquifer sections. Fe²⁺ and Mn²⁺ remained mobile in anoxic water upon approaching the recovery proximal zone, where Fe²⁺ precipitated via MnO₂ reduction, resulting in a dominating Mn²⁺ contamination. Recovery of Mn²⁺ and Fe²⁺ was counteracted by frequent injections of oxygen-rich water via the recovering well to form Fe and Mn-precipitates and increase sorption. The MPPW-ASR strategy exposes a much larger part of the injected water to the deeper geochemical units first, which may therefore control the mobilization of undesired elements during MPPW-ASR, rather than the average geochemical composition of the target aquifer.     

甘肃永靖黑方台4·29罗家坡黄土滑坡的特征

2015年4月29日上午,甘肃省永靖县盐锅峡镇黑方台滑坡高频发区的党川村罗家坡同一斜坡处连续发生了2次大规模黄土滑坡,总体积约65×10~4m~3,最大滑距630 m,摧毁14户居民房屋和3家工厂.通过现场详细调查、取样试验、1∶500地形测量、滑坡影像、视频等资料分析,对灌溉引发的罗家坡黄土滑坡的特征、滑动过程、形成机理进行了探讨.结果表明:第1次滑坡经过近2 a变形过程,整体突然失稳,高速远程滑动;第2次滑坡变形时间仅3 h,分块逐步滑动,滑动历时长而过程复杂,总体为低速远程滑动.高陡的地形和强度低、水敏感性强的土体是滑坡发生的基础,黄土台塬区长期农业灌溉是引发因素,大量水体入渗形成了20余米厚的饱和软弱基座,使抗剪强度降低,导致斜坡失稳滑动.黄土滑坡高速远程滑动的主要原因是滑坡剪出口位置高,滑动势能大,释放条件好,剪出口下部陡坡段为主要加速段;前方有开阔的滑动空间且有一定坡度、平缓的滑道;滑体底部饱和软弱黏性土在滑道上持续产生超孔隙水压力、液化等低摩阻效应,是远程滑动的润滑剂.同时,两次滑体间还存在冲击加速和能量传递作用.     

板桥-合水地区长63储层成岩相孔隙结构特征及优质储层分布

利用铸体薄片、扫描电镜、常规压汞、恒速压汞及相渗等资料,研究了板桥-合水地区长6₃储层成岩相类型及其微观孔隙结构特征,总结了不同成岩相的测井响应特征,确定了纵向及平面分布规律。结果表明优质成岩相的展布受沉积相、成岩作用与孔隙结构共同控制,尤其是喉道分布才是控制砂岩储层渗透性的主要因素。水云母胶结-残余粒间孔相和水云母胶结-长石溶蚀相储层主要分布于半深湖相重力流复合水道浊流沉积中,细-微细喉道发育,孔喉连通性好,渗流能力最好,油水呈相对均匀的渗流,孔隙内的油气极易通过喉道被开采出来;绿泥石胶结相、水云母胶结弱溶蚀相储层位于分支水道边缘,呈孤岛状分布,孔喉半径小但分布均匀,渗流能力中等-差;碳酸盐胶结相、碳酸盐+水云母胶结相储层主要发育在分支水道间,孔隙结构发育程度差,喉道细小且孔喉连通性差,富集于孔隙中的油气难以通过小喉道,采收率低。     

Hydrogen sulfide measurements in air by passive/diffusive samplers and high-frequency analyzer: A critical comparison

In this study, hydrogen sulfide (H₂S) measurements in air carried out using (a) passive/diffusive samplers (Radiello^® traps) and (b) a high-frequency (60 s) real-time analyzer (Thermo^® 450i) were compared in order to evaluate advantages and limitations of the two techniques. Four different sites in urban environments (Florence, Italy) and two volcanic areas characterized by intense degassing of H₂S-rich fluids (Campi Flegrei and Vulcano Island, Italy) were selected for such measurements. The concentrations of H₂S generally varied over 5 orders of magnitude (from 10⁻¹–10³ μg/m³), the H₂S values measured with the Radiello^® traps (H₂S_R) being significantly higher than the average values measured by the Thermo^® 450i during the trap exposure (H₂S_Ta), especially when H₂S was <30 μg/m³. To test the reproducibility of the Radiello^® traps, 8 passive/diffusive samplers were contemporaneously deployed within an 0.2 m² area in an H₂S-contaminated site at Mt. Amiata (Tuscany, Italy), revealing that the precision of the H₂S_R values was ±49%. This large uncertainty, whose cause was not recognizable, is to be added to that related to the environmental conditions (wind speed and direction, humidity, temperature), which are known to strongly affect passive measurements. The Thermo^® 450i analyzer measurements highlighted the occurrence of short-term temporal variations of the H₂S concentrations, with peak values (up to 5732 μg/m³) potentially harmful to the human health. The Radiello^® traps were not able to detect such temporal variability due to their large exposure time. The disagreement between the H₂S_R and H₂S_Ta values poses severe concerns for the selection of an appropriate methodological approach aimed to provide an accurate measurement of this highly toxic air pollutant in compliance with the WHO air quality guidelines. Although passive samplers may offer the opportunity to carry out low-cost preliminary surveys, the use of the high-frequency H₂S analyzer is preferred when an accurate assessment of air quality is required. In fact, the latter provides precise real-time measurements for a reliable estimation of the effective exposure to hazardous H₂S concentrations, giving insights into the mechanisms regulating the dispersion of this air pollutant in relation to the meteorological parameters.     

地震资料观测系统定义软件的研究与开发

地震资料处理过程中,观测系统的定义是不可或缺的关键步骤之一。在实际工作中通过对地震勘探观测系统定义的需求研究,使用Visual C++2010IDE结合Qt自主开发了一套针对陆上与海上通用的观测系统定义软件,该软件支持跨平台运行,提供了灵活多样的布设模式、直观的图形显示、面元网格划分和质量控制方式,在实际工区的使用过程中具备很强的实用性和可扩展性。     

基于随机森林模型的云南元阳梯田地形因子分析

为探究地形因子对梯田空间分布的影响,以云南元阳梯田坝达流域为研究区,运用GeoEye-1遥感卫星数据(2010年,1 m分辨率)和数字高程模型(20 m分辨率),提取梯田空间分布信息以及海拔高程、地形坡度、地形坡向、地面曲率、高程变异系数、地形起伏度、地面粗糙度、地表切割度、到水系距离9个地形因子。采用随机森林(Random Forest)方法建模,结合ROC曲线和AUC值对模型进行精度评价,根据随机置换残差均方减少量和因子作用曲线,探讨地形因子对梯田分布的影响规律。研究结果表明:该流域内梯田总面积1 158395 hm2,模型AUC值为0.947,海拔高度因子的随机置换残差均方减少量为38814,到水系距离因子为199.77,地面坡向因子为80.26,三者占总值的73.45%。由此可见,元阳梯田的空间分布主要受海拔高度、到水系距离、地面坡向3类地形因子的影响,其因子曲线表明梯田分布与地形因子间呈非线性关系。     

GIS综合评价模型在地质灾害详细调查中的应用

以河南省登封市地质灾害调查为例,在分析地质环境条件的基础上,总结地质灾害发育特征,确定易发性分区评价指标,并运用GIS综合评价模型分析计算,得出的分区结果与实际吻合较好。通过对GIS综合评价模型的研究,可为大区域内地质灾害易发性评价提供参考。     

基于GIS的青海高寒区矿山地质环境影响程度模糊评价

青海省的矿产资源主要分布于青藏高原高寒区,处于生态环境脆弱地区,具有独特的地质环境条件,生态环境保护与矿业的开发之间矛盾突出。本文以青海省东部大通河上游的江仓煤矿四井田为例,将影响矿山地质环境质量的主要矿山地质环境地质要素概括为自然因子和人为因子二大类。为尽可能实现多因素的影响和评价因子的量化,将评价因子划分为三级,建立了矿山地质环境影响程度评价指标体系。在GIS支持下,建立影响程度评价因子数据库。利用GIS空间栅格叠加分析功能,采用三级模糊综合评判方法对矿山地质环境影响程度进行了综合评价,编制了矿山地质环境影响程度评价图。基于GIS的矿山地质环境影响程度模糊评价方法将GIS技术和模糊数学理论引入矿山地质环境影响程度评价研究之中,达到了定性、定量以及定位相结合,从而可为受损的矿山地质环境实施科学保护与治理提供更加精确的信息。