基于PCA和在线监测技术研究旅游活动对岩溶地下水水化学的影响

岩溶地下水极易遭受污染且响应迅速,单靠几次取样难以揭示这种快速的动态过程。本研究采用高分辨率在线示踪技术确定了重庆金佛山水房泉的污染源位置,利用高密度监测获取了水房泉2014-12-01至2015-03-27期间水化学信息,同时定期获取流域内的大气降水、土壤水、景区假日酒店生活用水(以下简称宾馆用水)及污水样品。结果表明:投放在假日酒店卫生间的荧光素钠在水房泉的回收率为82%,示踪剂到达水房泉的最短时间和平均时间分别为26.8 h、90.3 h;水房泉泉水(以下简称泉水)在监测前期(2014-12-01至2014-12-14)和监测后期(2015-03-05至2015-03-27)大部分水化学指标的数值接近,监测中期出现的3次较大幅度的波动,与游客高峰期契合。主成分分析(PCA)提取了能代表75.0%信息量的2个主成分,旅游活动引起的pH值、溶解氧降低及电导率、盐度、浊度、K~+、Na~+、Ca~(2+)、Mg~(2+)、Sr~(2+)、全Fe、全Mn、SiO_2、HCO_3~–、Cl~–、PO_4~(3–)的上升,对本次监测信息的贡献率为61.2%;大气降水则导致泉水流量增加、水温降低,NO–3、Al~(3+)可能受到活塞效应的影响而增加,对本次监测信息贡献率为13.8%。旅游活动是影响该时段泉水水化学特征变化的主要因素。     

Regional Geochemistry and Fluid Flow in the Palaeogene Aquifers of the Gaoyou Subbasin in the Southern Part of North Jiangsu Basin, China

Chemical analysis of groundwater in petroliferous basins can be an effective way to determine the regional hydrogeological regime and to evaluate the preservation conditions of hydrocarbons. This paper presents the hydrochemical distribution of both individual aquifers and different structural units within the Palaeogene strata of the Gaoyou subbasin in the North Jiangsu Basin, east China. The results show that the salinity of the Palaeogene aquifers in the Gaoyou subbasin displays a systematic increase from the central deep depression to the periphery areas, and shows a reverse trend as the burial depth increases. Salinity maps of individual aquifers suggest that formation water in the deep layers at the centre of the study area probably retains original features of fresh lake water. Geofluids near the central deep depression of the Gaoyou subbasin migrate vertically through the Zhenwu and Hanliu faults, while those of the northern slope belt mainly flow laterally through aquifers. Both low and high salinity formation water can be found in the hydrocarbon producing areas. The low salinity zones commonly affected by infiltrated meteoric water are unfavourable conditions for the preservation of trapped hydrocarbons.     

基于水化学数据的矿山涌水水源识别:主成分分析与残差分析

涌水是矿山安全生产的重要威胁之一,掌握涌水的水源是预防这类灾害的重要依据。基于多期次的水化学监测数据,提出了利用主成分分析(PCA)和残差分析来识别涌水的水源数量和水源类型。主成分分析能够充分提取高维数据的结构信息,消除变量冗余。残差分析利用主成分分析结果,提取不同的主成分个数重构离子浓度,得出重构离子浓度和原始离子浓度之间的残差,利用残差的结构性信息来判断可能的涌水水源数量和水源类型。结果表明:随保留主成分个数的增加,重构离子浓度的精度越高,离子残差的结构性得到消除且表现出随机性。在实例应用中,通过利用5个主成分重构离子浓度消除了所有主要离子残差结构性,保证了信息的最大程度提取,因此,确定研究矿山涌水水源数量为5个;同时,利用每个主成分对残差结构性的影响程度及离子相关性分析,确定了这5个水源类型为海水、第四系孔隙水、富钙基岩水、富镁基岩水和淡水。     

ONWET: A Simple Integrated Tool for Beach Morphology and Wave Dynamics Analysis

The analysis of beach profile combined with wave data provides a clear understanding of beach topography and physical behavior of the coast. Numerous commercial and noncommercial computer programs and add-on tools are available to analyze beach profile and wave data. But, most of them are specifically designed for particular coastal application. Moreover, searching of open source software for diverse coastal application is a tedious process. To make it easily accessible, we have developed an integrated Matlab GUI for beach morphology and wave analysis. The tool “ONWET (OceaN WavE Tool)” mainly includes wave processes, beach morphology, spatiotemporal variation in beach profile, wave refraction, and sediment transport rate. The tool has automated inbuilt functions and is designed to accommodate importing/exporting of data (results both in data and graphical format). It includes user friendly options and can be freely download from our institutional website. The tool is very useful for researchers, scientists, engineers, and environmentalists who are working in the field of coastal studies and beach nourishment.     

校园能源监管WebGIS的设计与实现

"校园能源监管平台"作为校园能源管理的有效手段,建设形式多以信息管理系统为主,缺乏地理信息直观表达和分析能力。本文将WebGIS引入能源监管平台建设,结合Flex、ASP.NET技术,构建B/S模式的"校园能源监管WebGIS系统"。利用服务接口技术进行系统构架设计,保证对现有能源监管平台改动的最小化,通过二维三维相结合的方式对能源信息进行展示,提高能源信息地理位置的直观性,通过构管线管理和路灯控制等功能模块,有效增强能源地理信息管理和分析能力,为能源监管平台建设提供了一种新思路。     

High‐frequency precipitation and stream water quality time series from Plynlimon,Wales: an openly accessible data resource spanning the periodic table

This scientific briefing announces the availability of a new multi‐element high‐frequency water quality data set that is openly accessible to the research community. The data set comprises up to 2 years of 7‐hourly water quality data for two streams and one rainfall site in the Upper Severn catchment at Plynlimon in Mid‐Wales. The measurements cover 50 analytes ranging from H⁺ to U and spanning six orders of magnitude in concentration, including major, minor and trace elements as well as nutrients, and they complement decades of weekly measurements of the same analytes at the Upper Severn. Together, the weekly and 7‐hourly time series provide a unique data set for studying both long‐term trends and short‐term dynamics. The data show complex behaviour over a wide range of timescales, challenging our understanding of catchment processes and informing future modelling efforts. Copyright © 2013 John Wiley & Sons, Ltd.     

Dating of raised marine and lacustrine deposits in east Greenland using beryllium‐10 depth profiles and implications for estimates of subglacial erosion

Here we combine ¹⁰Be depth profile techniques applied to late glacial ice‐contact marine and lacustrine deltas, as well as boulder exposure dating of associated features in the Scoresby Sound region, east Greenland, to determine both the surface age and the magnitude of cosmogenic nuclide inheritance. Boulder ages from an ice‐contact delta in northern Scoresby Sund show scatter typical of polar regions and yield an average age of 12.8 ± 0.5 ka – about 2 ka older than both our average profile surface age of 10.9 ± 0.7 ka from three depth profiles and a radiocarbon‐based estimate. On the other hand, boulder exposure ages from a set of moraines in southern Scoresby Sund show excellent internal consistency for polar regions and yield an average age of 11.6 ± 0.2 ka. The profile surface age from a corresponding ice‐contact delta is 8.1 ± 0.9 ka, while a second delta yields an age of 10.0 ± 0.4 ka. Measured ¹⁰Be inheritance concentrations from all depth profiles are internally consistent and are between 10% and 20% of the surface concentrations, suggesting a regional cosmogenic inheritance signal for the Scoresby Sound landscape. Based on the profile inheritance concentrations, we explore the first‐order catchment‐averaged bedrock erosion under the Greenland ice sheet, yielding estimates of total erosion during the last glacial cycle of the order of 2–30 m. Copyright © 2010 John Wiley & Sons, Ltd.     

Rethinking the longitudinal stream temperature paradigm: region‐wide comparison of thermal infrared imagery reveals unexpected complexity of river temperatures

Prevailing theory suggests that stream temperature warms asymptotically in a downstream direction, beginning at the temperature of the source in the headwaters and levelling off downstream as it converges to match meteorological conditions. However, there have been few empirical examples of longitudinal patterns of temperature in large rivers due to a paucity of data. We constructed longitudinal thermal profiles (temperature vs distance) for 53 rivers in the Pacific Northwest (USA) using an extensive data set of remotely sensed summertime river temperatures and classified each profile into one of five patterns of downstream warming: asymptotic (increasing then flattening), linear (increasing steadily), uniform (not changing), parabolic (increasing then decreasing), or complex (not fitting other classes). We evaluated (1) how frequently profiles warmed asymptotically downstream as expected, and (2) whether relationships between river temperature and common hydroclimatic variables differed by profile class. We found considerable diversity in profile shape, with 47% of rivers warming asymptotically and 53% having alternative profile shapes. Water temperature did not warm substantially over the course of the river for coastal parabolic and uniform profiles, and for some linear and complex profiles. Profile classes showed no clear geographical trends. The degree of correlation between river temperature and hydroclimatic variables differed among profile classes, but there was overlap among classes. Water temperature in rivers with asymptotic or parabolic profiles was positively correlated with August air temperature, tributary temperature and velocity, and negatively correlated with elevation, August precipitation, gradient and distance upstream. Conversely, associations were less apparent in rivers with linear, uniform or complex profiles. Factors contributing to the unique shape of parabolic profiles differed for coastal and inland rivers, where downstream cooling was influenced locally by climate or cool water inputs, respectively. Potential drivers of shape for complex profiles were specific to each river. These thermal patterns indicate diverse thermal habitats that may promote resilience of aquatic biota to climate change. Without this spatial context, climate change models may incorrectly estimate loss of thermally suitable habitat. Copyright © 2015 John Wiley & Sons, Ltd.     

热带太平洋温度异常变化对高空大气温度的影响

对热带17层气温纬向偏差垂直剖面和气温异常垂直剖面进行了分析,发现热带太平洋大尺度准定常热源温度波和下垫面温度异常温度波都能激发温度偶极振子,使温度波波及对流层和平流层高空,不仅改变了高空大气的热力状态,也使大气热力状态随高度的分布呈现出明显的波状结构。     

模糊聚类方法研究堤坝渗漏

稳定同位素、水化学的方法是研究堤防渗漏是一种十分有效的方法,以往人们大多只是定性的分析判断。结合北江大堤工程实例,尝试应用模糊聚类方法,选取22个水样稳定同位素和水化学值作为指标特征值,并赋与不同的权重,进行模糊聚类分析,聚类结果表明,T12孔和T9孔北5 m处涌水、江水和T9孔北排水沟出水在稳定同位素和水化学成分的Cl-及TDS上表现出了较大的相关性,可能为同一补给来源,为堤坝渗漏通道的判断提供了佐证。