基于多时相卫星数据的采砂场遥感调查研究——以青海省湟水流域为例

文章采用多源多时相高分辨率遥感影像作为数据源,以ArcGIS、Erdas、Envi等遥感地信软件为信息提取平台,对青海省湟水流域的采砂场进行遥感调查分析。结果显示：①采砂场主要分布在湟水流域城市周边,其中,在用采砂场分布较密集,如西宁、湟中、平安附近分布较集中,而停用采砂场分布相对比较均匀;②采砂场共305处,其中长期和临时采砂场占重要比例,达73%,经过平整或绿化的停用采砂场较少,而停用且无整改及整改中的采砂场数量仍较多,是已整改的2倍;③长期采砂场面积规模占所有类型总面积的比重最大,达三分之二,而经过平整或已绿化的规模仅0.75 km²。研究以期对环境监察管理提供技术支撑,为后续的研究和砂场的高效精准管理提供技术方法和科学依据。     

基于改进灰色关联分析法的丹江口流域地表水环境质量评价

改进水环境质量评价方法对于提高水环境管理水平具有重要意义。根据传统灰色关联分析原理,采用"中心化"的灰色关联无量纲化处理方法,对丹江口流域2012年河流中11个典型断面水体污染因子进行评价。结果表明,参评的11个断面中有9个符合地表水Ⅱ类水质标准,2个断面符合地表水Ⅳ类水质标准,整体水质满足国家南水北调水源地水质标准要求,改进的灰色关联分析方法在评价水质时较为科学、合理。     

岷江上游干旱河谷海拔梯度上四川黄栌(Cotinus szechuanensis)叶片的生态解剖

运用生态解剖学的方法对岷江上游干旱河谷海拔梯度上乡土优势灌木——四川黄栌(Cotinus szechuanensis)的叶片解剖特征进行了比较分析.观测的解剖学参数有叶片总厚度、表皮厚度、栅栏组织厚度(P)、海绵组织厚度(S)、P/S的比值、主脉厚度(V)、主脉中直径>50μm导管分子的数目及直径.结果表明:1)四川黄栌叶片具有中生型结构特征,但在不同海拔高度存在差异,这是其适应干旱环境的结构基础.随着海拔的升高,叶总厚度、栅栏组织厚度、P/S值和主脉厚度以及导管分子数目等均呈增大趋势,而导管分子直径减小;表皮厚度、海绵组织厚度等无明显差异.2)多元统计分析显示,叶肉组织厚度和叶片总厚度主要受温和度的影响,并随着温和度的降低而增大;P/S值和导管分子数目主要与年降水量和土壤含水量的变化有关,随着水分增加,P/S值和导管分子数目增大,而导管分子直径减小.因此,岷江上游干旱河谷地区年降雨量、土壤含水量与温和度是影响四川黄栌叶片解剖结构的主要环境因子.图1表3参28     

The paradox of the modernisation of urban water systems in Europe: Intrinsic institutional limits for sustainability

This article assesses the sustainability potential of the urban water systems in Europe (UWSE) following their modernisation. A decade after implementation and close to the first deadlines, modernisation efforts seem to have not been (totally) successful. This article examines the ability of governance to achieve sustainability and poses the question of how modernisation develops a particular “terrain” more or less favourable to sustainability. We use the Institutional resource regimes framework which has been dedicated to determining the potential for sustainability of natural resources regulation. Conclusions show that the modernisation of UWSEs offers a path for progress which though necessary is insufficient due to a lack of coherence between policy design and the regulatory system. Globally, the development of regulation goes hand in hand with increasing inconsistencies that reduce the efficiency of the reform.     

Effects of red light camera enforcement on fatal crashes in large U.S. cities

Objective

To estimate the effects of red light camera enforcement on per capita fatal crash rates at intersections with signal lights.

Methods

From the 99 large U.S. cities with more than 200,000 residents in 2008, 14 cities were identified with red light camera enforcement programs for all of 2004-2008 but not at any time during 1992-1996, and 48 cities were identified without camera programs during either period. Analyses compared the citywide per capita rate of fatal red light running crashes and the citywide per capita rate of all fatal crashes at signalized intersections during the two study periods, and rate changes then were compared for cities with and without cameras programs. Poisson regression was used to model crash rates as a function of red light camera enforcement, land area, and population density.

Results

The average annual rate of fatal red light running crashes declined for both study groups, but the decline was larger for cities with red light camera enforcement programs than for cities without camera programs (35% vs. 14%). The average annual rate of all fatal crashes at signalized intersections decreased by 14% for cities with camera programs and increased slightly (2%) for cities without cameras. After controlling for population density and land area, the rate of fatal red light running crashes during 2004-2008 for cities with camera programs was an estimated 24% lower than what would have been expected without cameras. The rate of all fatal crashes at signalized intersections during 2004-2008 for cities with camera programs was an estimated 17% lower than what would have been expected without cameras.

Conclusions

Red light camera enforcement programs were associated with a statistically significant reduction in the citywide rate of fatal red light running crashes and a smaller but still significant reduction in the rate of all fatal crashes at signalized intersections.

Impact on Industry

The study adds to the large body of evidence that red light camera enforcement can prevent the most serious crashes. Communities seeking to reduce crashes at intersections should consider this evidence.     

Climate change adaptation planning for Global South megacities: the case of Dhaka

Megacities in low- and middle-income countries face unique threats from climate change as vulnerable populations and infrastructure are concentrated in high-risk areas. This paper develops a theoretical framework to characterize adaptation readiness in Global South cities and applies the framework to Dhaka, Bangladesh, a city with acute exposure and projected impacts from flooding and extreme heat. To gather case evidence from Dhaka we draw upon interviews with national and municipal government officials and a review of planning documents and peer-reviewed literature. We find: (1) national-level plans propose a number of adaptation strategies, but urban concerns compete with priorities such as protection of coastal assets and agricultural production; (2) municipal plans focus on identifying vulnerability and impacts rather than adaptation strategies; (3) interviewees suggest that lack of coordination among local government (LG) organizations and lack of transparency act as barriers for municipal adaptation planning, with national plans driving policy where LGs have limited human and financial resources; and (4) we found limited evidence that national urban adaptation directives trickle down to municipal government. The framework developed offers a systematic and standardized means to assess and monitor the status of adaptation planning in Global South cities, and identify adaptation constraints and opportunities.     

数字尾矿库系统结构及功能实现方法

我国三等以上尾矿库均建成了尾矿库在线监测系统,为进一步提升尾矿库管控水平,提出可在在线监测系统基础上建设数字尾矿库工程的思路。数字尾矿库工程是借助全数字测量、遥感、地理信息系统或全球定位系统等现代化手段采集基础数据,实现尾矿库地形地势、水文气象、监测监控、调洪、尾矿坝稳定、风险分析、设备设施管理、应急培训等功能有机集成的统一管控平台。在总结数字尾矿库研究现状的基础上,借鉴水利水电工程中数字黄河、数字长江工程建设理论和方法,研究了数字山谷型尾矿库系统的功能和实现方法,提出了数字山谷型尾矿库系统的结构框架,并对数字平台建设、调洪演算实现、坝体稳定在线分析预警及应急培训等子系统的实现方法进行了深入研究,研究成果可为后期数字尾矿库建设提供参考。     

城市间气态污染物与细颗粒物的相关性分析

通过对沿太行山脉东侧城市间环境空气污染物浓度监测数据分析发现,大气污染是一个区域性问题,相近城市间主要污染物浓度均呈高度正相关。以北京、石家庄、保定和邢台作为研究对象,对其2013年主要大气污染物浓度变化趋势进行分析对比,建立污染物浓度相关性分析模型,并对各污染因子间的相关性进行研究,得到各地区的污染物相关性结果,为区域协同控制大气污染提供决策支持。     

2013—2016年74城市臭氧浓度变化特征

利用2013—2016年74城市臭氧（O₃）监测数据,综合探讨了全国74城市O₃浓度时空变化特征、变化趋势。结果表明：2013—2016年,74城市O₃-8 h各百分位浓度总体呈上升趋势,且百分位较高区间O₃浓度逐年上升速率越快,O₃-8 h第95百分位浓度年增长5.3 μg/m³,其次是第90百分位;O₃区域性污染特征明显,京津冀及周边、长三角、珠三角O₃污染问题突出;74城市O₃浓度超标天数年增长3 d/城市,O₃污染呈明显日、季节变化特征,午后14：00—17：00达到小时浓度峰值,超标日主要集中于5—10月;O₃对环境空气质量综合指数贡献率逐年增加,北京、上海和广州O₃贡献率年增长分别为1.9%、1.1%和0.8%。     

基于微空间单元的岩溶峡谷区土地利用结构演变

采用2004年、2010年和2015年分辨率均为2.5 m的SPOT等遥感影像和社会经济数据,创建200 m×200 m网格的微空间单元,计算单元网格内地类面积占比、土地利用程度综合指数,并结合双变量局部空间自相关和热点分析法,深入研究岩溶峡谷区土地利用结构演变特征。结果表明:(1)2004年林地、耕地、聚落和裸岩裸土网格内平均占比分别为6.46%、11.76%、0.87%、28.86%,2010年分别为10.36%、8.77%、1.27%、27.13%,2015年分别为9.13%、10.30%、26.18%、1.29%;(2)各种土地利用类型在空间分布上具有明显的空间差异特征;(3)耕地热点区呈减少趋势,且后期主要集中在研究区西南部,林地热点区总体增加,裸岩裸土极热点区逐渐向研究区东北部收缩。而近几年土地利用程度热点区逐渐向研究区西北部延伸,花椒林则主要分布于北部干热河谷地带。简而言之,花江峡谷区林地面积增加,且逐渐向集中连片演变,而裸岩地逐渐向峡谷区北部以及东北部收缩,研究区农户生计多样化发展及交通条件的改善,使得土地压力减小,生态环境逐渐转好。本文以典型岩溶地貌单元为代表,揭示中...