Land cover effects on water balance partitioning in the Colombian Andes: improved water availability in early stages of natural vegetation recovery

Regional Environmental Change - Vegetation actively affects different components of the water budget in multiple spatial and temporal scales. Changes in vegetation cover and structure—such as...     

安徽省用水网络管理与关键区域界定

基于2005~2016年安徽省16个城市的用水量数据,利用社会网络分析（SNA）方法刻画了区域用水空间关联的网络结构特征,并进一步对水资源管理重点区域进行了筛选。研究发现：安徽省域内的用水联系紧密,不存在孤立的城市节点,样本考察期内,区域用水空间关联的网络密度有所下降,但呈现为等级森严的网络结构;个体网络特征表现出明显的“极化效应”和“马太效应”,合肥、马鞍山和芜湖具有较高的度数中心度、中间中心度和接近中心度,处于网络中的核心位置,主导着关联网络中水资源的流动和溢出;目前安徽省区域用水网络处于多核心阶段,且由初期的合肥和马鞍山-芜湖-铜陵双核驱动模式逐步演变成以阜阳、合肥和马鞍山-芜湖-铜陵为三大增长极的空间稳定格局。     

Analyzing the Variability of Remote Sensing and Hydrologic Model Evapotranspiration Products in a Watershed in Michigan

The goal of this paper was to statistically explore the spatiotemporal performance of remotely sensed actual evapotranspiration (ETa) datasets and a remotely sensed ensemble in a region that lacks observed data. The remotely sensed datasets were further compared with ETa results from a physically based hydrologic model (Soil and Water Assessment Tool) to examine the differences and determine the level of agreement between the ETa datasets and the model outputs. ETa datasets were compared on temporal (i.e., monthly and seasonal basis) and spatial (i.e., landuse) scales at both watershed and subbasin levels. The results showed a lack of consistent similarities and differences among the datasets when evaluating the monthly ETa variations; however, the seasonal aggregated data presented more consistent similarities and differences during the spring and summer compared to the fall and winter. Meanwhile, spatial analysis of the datasets showed the MOD16A2 500 m ETa product was the most versatile of the tested datasets, being able to differentiate between landuses during all seasons. Furthermore, the use of an averaging ensemble was able to improve overall ETa performance in the study area. This study showed that the remotely sensed ETa products are not similar throughout the year, but the appropriate application periods for different ETa products were identified. Finally, spatial variabilities of the ETa products are more in tune with landuse and climate characteristics.     

青藏高原东部过渡区水环境中全氟化合物的分布特征

为探究高原过渡区水环境中全氟化合物(perfluorinated compounds,PFCs)的污染状况,以青藏高原东部过渡区典型高山峡谷区、若尔盖草原湿地区为研究区,应用固相萃取结合高效液相色谱-电喷雾负电离源串联质谱的方法对研究区内的降雪样品、河水和草原湿地地表径流样品中的全氟化合物进行测定.降雪样品中平均∑PFCs浓度为6266 pg·L~(-1),共检出11种PFCs,其中PFBA含量最高,表明该地区的大气中存在着以PFBA为主的PFCs污染.河水样品中检测到7种PFCs,高山峡谷区河水样品中ΣPFCs浓度范围为272—2244 pg·L~(-1),若尔盖草原湿地区河水样品中ΣPFCs浓度范围为727—5149 pg·L~(-1),远低于我国东部地区及长江黄河下游区域.若尔盖草原湿地地表径流样品检测出11种PFCs,∑PFCs浓度范围为5837—13720 pg·L~(-1),高于当地河水中PFCs的浓度,表明地表径流是当地河水中PFCs不可忽略的非点源污染源.运用熵值法得到青藏高原东部过渡区河水中PFOA、PFOS及PFBA的风险值均远低于参考值,未达到对生态环境具有风险的水平.     

Organochlorine pesticides in feathers of three raptor species in southern Brazil

Environmental Science and Pollution Research - In this study, we determined the presence of organochlorine pesticides (OCPs) in back feathers from three raptor species, Phalcoboenus chimango,...     

江淮地区秋季一次典型污染过程分析

结合2018年10月15—20日国控站点监测数据、气象资料及激光雷达走航观测结果,对江淮地区一次重度污染过程进行了分析。利用拉格朗日粒子扩散模型和拉格朗日混合单粒子轨迹模型定性分析了区域污染来源,分别基于激光雷达和空气站实测数据提出了外来源占比的估算方法,结合嵌套网格空气质量预报模式(NAQPMS)的源解析结果,对比分析了外来源占比。以淮北市为例,结合NAQPMS和单颗粒气溶胶质谱的PM2.5在线源解析结果,对比分析此次污染过程的行业来源。结果表明,本地污染累积时段,主要以燃煤和机动车尾气混合源为主(占比>70%);受北方污染输送时段,机动尾气占比显著升高,从19.4%(16日00:00)升至66.7%(17日11:00),淮北市、蚌埠市、合肥市3个城市污染物外来输送占比分别为52.2%~70.6%、48.8%~58.8%、41.5%~59.0%。     

城市道路积尘PM 2.5碳组分春秋季节差异分析

为了解城市道路积尘PM 2.5中碳组分春秋季节差异,利用样方法采集石家庄市4种不同类型道路积尘PM 2.5样品,测定有机碳(OC)和元素碳(EC)浓度并分析。结果表明:OC,EC在积尘PM 2.5中平均浓度春季为86.77,12.11 mg/g,秋季为119.70,9.44 mg/g,秋季OC浓度大于春季,EC相反;OC/EC为6.4~7.9(春季)和11.36~17.49(秋季),存在严重的二次污染,秋季明显高于春季。与国内不同地区对比发现,石家庄市道路积尘中碳质颗粒物污染严重。主成分分析发现春季积尘中的碳主要来自于汽油车与柴油车尾气排放、道路降尘的沉积,而秋季则增加了生物质燃烧、燃煤排放的影响。     

Modelling the Ecological Vulnerability to Forest Fires in Mediterranean Ecosystems Using Geographic Information Technologies

Forest fires represent a major driver of change at the ecosystem and landscape levels in the Mediterranean region. Environmental features and vegetation are key factors to estimate the ecological vulnerability to fire; defined as the degree to which an ecosystem is susceptible to, and unable to cope with, adverse effects of fire (provided a fire occurs). Given the predicted climatic changes for the region, it is urgent to validate spatially explicit tools for assessing this vulnerability in order to support the design of new fire prevention and restoration strategies. This work presents an innovative GIS-based modelling approach to evaluate the ecological vulnerability to fire of an ecosystem, considering its main components (soil and vegetation) and different time scales. The evaluation was structured in three stages: short-term (focussed on soil degradation risk), medium-term (focussed on changes in vegetation), and coupling of the short- and medium-term vulnerabilities. The model was implemented in two regions: Aragón (inland North-eastern Spain) and Valencia (eastern Spain). Maps of the ecological vulnerability to fire were produced at a regional scale. We partially validated the model in a study site combining two complementary approaches that focused on testing the adequacy of model’s predictions in three ecosystems, all very common in fire-prone landscapes of eastern Spain: two shrublands and a pine forest. Both approaches were based on the comparison of model’s predictions with values of NDVI (Normalized Difference Vegetation Index), which is considered a good proxy for green biomass. Both methods showed that the model’s performance is satisfactory when applied to the three selected vegetation types.     

四川省出川断面主要污染物通量及来源研究

以2001～2007年实测水文、水质数据为基础,计算了四川省主要出川断面高锰酸盐指数(CODMn)和氨氮(NH3-N)污染负荷通量;利用断面水质目标约束,通过污染负荷历时曲线,分析了区域水环境承载力;在基流分割的基础上,利用水文分割法,识别了区域污染物的主要来源,为从源头上开展三峡水库水环境保护提供数据支撑。分析结果表明,各出川断面干流主要污染物(CODMn、NH3-N)大致在可接受的范围内,2001年以来,出川断面CODMn通量呈降低的趋势,有效的减缓了输入三峡库区的污染物总量,氨氮通量整体稳定。嘉陵江、涪江、渠江流域污染物来源主要为非点源,应重点加强面源的污染防控;长江干流为点面源混合型,简单的削减点源已不能保证高功能水体要求,应加强点源和面源污染的综合防控。     

吉林省区域功能空间结构演变分析

基于空间重心的地图演示方法,以吉林省为例,采用土地利用数据和经济统计数据,对比区域功能空间重心和经济重心的转移变化轨迹,从空间效率差异视角认识区域发展的不平衡性。结果显示:①吉林省区域功能空间差异明显,形成了东部生态、中部社会经济、中西(偏西)部农业的功能空间格局;②1995-2007年,吉林省区域空间结构整体稳定,局部优化调整,耕地保护和城市扩张过程中的矛盾冲突初步缓解,社会经济功能空间重心向中部城市优势区位地带转移;③1995-2007年,吉林省经济重心趋向第二三产业重心,社会经济功能空间重心和经济重心从相反方向分别向中部城市收敛,东西部空间效率趋向平衡;④空间组织应当更加重视对区域发展目标的支撑,吉林省宜进一步稳定既有区域空间格局,继续提高中部城市(群)的经济集聚效用。