Groundwater flow and storage processes in an inactive rock glacier

Groundwater flow through coarse blocky landforms contributes to streamflow in mountain watersheds, yet its role in the alpine hydrologic cycle has received relatively little attention. This study examines the internal structure and hydrogeological characteristics of an inactive rock glacier in the Canadian Rockies using geophysical imaging techniques, analysis of the discharge hydrograph of the spring draining the rock glacier, and chemical and stable isotopic compositions of source waters. The results show that the coarse blocky sediments forming the rock glacier allow the rapid infiltration of snowmelt and rain water to an unconfined aquifer above the bedrock surface. The water flowing through the aquifer is eventually routed via an internal channel parallel to the front of the rock glacier to a spring, which provides baseflow to a headwater stream designated as a critical habitat for an at‐risk cold‐water fish species. Discharge from the rock glacier spring contributes up to 50% of basin streamflow during summer baseflow periods and up to 100% of basin streamflow over winter, despite draining less than 20% of the watershed area. The rock glacier contains patches of ground ice even though it may have been inactive for thousands of years, suggesting the resiliency of the ground thermal regime under a warming climate.     

Mapping groundwater discharge to a coastal lagoon using combined spatial airborne thermal imaging,radon (222Rn) and multiple physicochemical variables

Coastal lagoons are significant wetland environments found on coastlines throughout the world. Groundwater seepage may be a key component of lagoon water balances, though only a few studies have investigated large (>100 km²) coastal lagoons. In this study, we combined airborne thermal infrared imagery with continuous measurements of radon (²²²Rn—a natural groundwater tracer), conductivity, water temperature and dissolved oxygen to map groundwater seepage to a large coastal lagoon in New Zealand. We found evidence of seepage along the margins of the lagoon but not away from the margins. Our findings confirmed previously known seepage zones and identified new potential locations of groundwater inflow. Both point source and diffuse seepage occurred on the western and northwestern margins of the lagoon and parallel to the barrier between the lagoon and sea. These observations imply geologic controls on seepage. The combination of remote sensing and in-situ radon measurements allowed us to effectively map groundwater discharge areas across the entire lagoon. Combined, broad-scale qualitative methods built confidence in our interpretation of groundwater discharge locations in a large, dynamic coastal lagoon.     

GGR Biennial Critical Review: Analytical Developments Since 2010

Advances in the chemical and isotopic characterisation of geological and environmental materials can often be ascribed to technological improvements in analytical hardware. Equally, the creation of novel methods of data acquisition and interpretation, including access to better reference materials, can also be crucial components enabling important breakthroughs. This biennial review highlights key advances in either instrumentation or data acquisition and treatment, which have appeared since January 2010. This review is based on the assessments by scientists prominent in each of the given analytical fields; it is not intended as an exhaustive summary, but rather provides insight from experts of the most significant advances and trends in their given field of expertise. In contrast to earlier reviews, this presentation has been formulated into a unified work, providing a single source covering a broad spectrum of geoanalytical techniques. Additionally, some themes that were not previously emphasised, in particular thermal ionisation mass spectrometry, accelerator‐based methods and vibrational spectroscopy, are also presented in detail.     

Hyperspectral image analysis of different carbonate lithologies (limestone,karst and hydrothermal dolomites): the Pozalagua Quarry case study (Cantabria,North‐west Spain)

Ground‐based hyperspectral imaging combined with terrestrial lidar scanning is a novel technique for outcrop analysis, which has been applied to Early and Late Albian carbonates of the Pozalagua Quarry (Cantabrian Mountains, Spain). An image processing workflow has been developed for differentiating limestone from dolomite, providing additional sedimentary and diagenetic information, and the possibility to quantitatively delineate diagenetic phases in an accurate way. Spectral absorption signatures can be linked to specific sedimentary or diagenetic products, such as recent and palaeokarst, hydrothermal karst, (solution enlarged) fractures and different dolomite types. Some of the spectral signatures are related to iron, manganese, organic matter, clay and/or water content. Ground‐truthing accessible parts of the quarry showed that the classification based on hyperspectral image interpretation was very accurate. This technique opens the possibility for quantitative data evaluation on sedimentary and diagenetic features in inaccessible outcrops. This study demonstrates the potential of ground‐based imaging spectroscopy to provide information about the chemical–mineralogical distribution in outcrops, which could otherwise not be established using conventional field methods.     

Electrical resistivity imaging and hydrochemical analysis for groundwater investigation in Kuala Langat,Malaysia

ABSTRACT

Integrated two-dimensional electrical resistivity imaging (ERI) and hydrochemical surveys were used to investigate the groundwater alluvial aquifer in Kuala Langat, Malaysia. The study in the Langat basin considered the thickness of the aquifer, the depth of the bedrock, the regions influenced by seawater intrusion, and the monitoring of water levels. The resistivity imaging results show that the upper layer consists of clay, while the second layer is an aquifer whose thickness varies mostly in the range of 10–30 m, and in some cases extends to 40 m. The bedrock depth varies from 30 to 65 m. The chemical analyses were carried out on groundwater samples from nine boreholes collected between 2008 and 2012. The analyses indicate that the total dissolved solids (TDS) exceed 1000 mg L^-1 near the coastal area and are often less than 500 mg L^-1 further inland. The ERI and hydrochemical analyses reveal that groundwater in the study area, especially towards the coast, is a mixture of brackish and fresh waters.

EDITOR D. Koutsoyiannis; ASSOCIATE EDITOR M.D. Fidelibus     

支持地图跨媒体出版的符号库研究

本文从色空间、图形描述机制、语法规则以及执行模式等方面分析了地图跨媒体发布所涉及到的各类图形格式、技术和标准之间的异同及其对地图符号库构建的影响:从地图符号的构图规律出发,引入通用的二维成像模型,提出一种媒介中立的地图符号数据结构,设计了一种同时支持地图屏幕显示、制版印刷、网络发布的地图符号库;并构建了原型系统,验证了该符号库支持地图跨媒体输出的可行性。     

An operational method for fast detecting abnormal channels in imaging spectrometers

Data from abnormal channels in an imaging spectrometer almost always exerts an undesired impact on spectrum matching, classification, pattern recognition and other applications in hyperspectral remote sensing. To solve this problem, researchers should get rid of the data acquired by these channels. Selecting abnormal channels just in the way of visually examining each band image in a imaging data set is a conceivably hard and boring job. To relieve the burden, this paper proposes a method which exploits the spatial and spectral autocorrelations inherent in imaging spectrometer data, and can be used to speed up and, to a great degree, automate the detection of abnormal channels in an imaging spectrometer. This method is applied easily and successfully to one PHI data set and one Hymap data set, and can be applied to remotely sensed data from other hyperspectral sensors.     

资源一号02C卫星全色相机在轨几何定标方法

为提高资源一号02C卫星全色影像几何精度,首先从其严格几何成像模型出发,对成像过程中的几何误差来源及其特性进行分析,在此基础上构建资源一号02C卫星全色相机的在轨几何定标模型;然后,将待定标参数分为内外定标参数,采用分步迭代策略进行解算;最后,基于本文的定标模型及解算方法,利用嵩山定标场提供的高精度参考数据对其进行了在轨几何定标实验。实验结果表明,本文的定标模型及解算方法合理有效,能显著提高资源一号02C卫星全色影像的无控定位精度和有控定位精度;同时,内定标精度优于0.3个像元。     

冠状动脉前瞻性心电门控窄窗采集技术在320排螺旋CT中的应用

目的：探讨使用320排螺旋CT前瞻性心电门控窄窗采集技术,在降低辐射剂量方面的应用。方法：研究组50例采用前瞻性心电门控技术,对照组50例患者采用回顾性心电门控技术,分别测量两组间图像质量以及辐射剂量。结果：两组数据比较,患者的基本情况如年龄、心率、体重和体重指数以及图像质量差异无统计学意义（P〉0．05）,有效放射剂量两组间的差异有统计学意义（P=0．0001）,前瞻性心电门控组辐射剂量（8．80±2．78）mSv显著低于回顾心电门控组（25．82±8．84）mSv。结论：前瞻性心电门控窄窗采集技术在确保图像质量的同时可以降低辐射剂量。