Automated correction of systematic errors in high frequency depth measurements above V-notch weirs using time series decomposition     

Jason A. Regina  Fred L. Ogden 《水文研究》2021,35(12):e14405

Hydrologic studies require high-quality streamflow measurements. V-notch weirs provide accurate discharge measurements and when properly equipped produce continuous records of streamflow. However, sensor drift and accumulations of floating woody debris cause systematic errors in depth measurements behind weirs, particularly during periods of base flow between storms. Manual processing of high-frequency streamflow data is often subjective and difficult to reproduce. We developed a method to automatically correct erroneous depth time series to accelerate data processing and promote objectivity and reproducibility. The method inspects depth measurements, isolates and preserves periods of direct runoff during storms, and corrects erroneous inter-event baseflow. We applied experience obtained during manual data processing to implement an automatic correction method based on time series decomposition to produce a consistent time series of stage data that eliminates obvious errors due to sensor drift and clogging by woody debris. The automatic method offers an objective and reproducible procedure capable of efficiently processing 1 year of stage data in seconds. This method promotes reproducibility and may appeal to water resources experts working with large amounts of data especially at sites where distance, cost, or inclement weather prevents regular instrument maintenance.  相似文献   

Unravelling the moisture sources of the Alpine glaciers using tunnel valleys as constraints          下载免费PDF全文

Regina Reber  Fritz Schlunegger 《地学学报》2016,28(3):202-211

A lack of archives has impeded reconstructions of moisture pathways for past glaciations in the European Alps. Here, we focus on the confluence area of two palaeoglaciers in the Swiss Plateau that were sourced on the northern (Aare glacier) and southern sides (Valais glacier) of the European Alps. We mapped tunnel valleys in the region using a drilling database, based on which we inferred the relative extent of each glacier c. 270 ka ago when the valleys were formed. We then compared this situation with that of the LGM. We found that, while the Valais glacier expanded farther into the foreland than the Aare glacier during the LGM, the opposite was the case c. 270 ka ago. We also found that LGM glaciers were non‐erosive in the distal foreland. These contrasts in extents and erosional efficiencies imply differences in moisture pathways between the LGM and the time when the tunnel valleys were formed.  相似文献   

Net Ecosystem Metabolism and Nonconservative Fluxes of Organic Matter in a Tropical Mangrove Estuary, Piauí River (NE of Brazil)     

Marcelo F. L. Souza  Viviane R. Gomes  Simone S. Freitas  Regina C. B. Andrade  Bastiaan Knoppers 《Estuaries and Coasts》2009,32(1):111-122

Net ecosystem metabolism (NEM) was measured in the Piauí River estuary, NE Brazil. A mass balance of C, N, and P was used to infer its sources and sinks. Dissolved inorganic carbon (DIC) concentrations and fluxes were measured over a year along this mangrove dominated estuary. DIC concentrations were high in all estuarine sections, particularly at the fluvial end member at the beginning of the rainy season. Carbon dioxide concentrations in the entire estuary were supersaturated throughout the year and highest in the upper estuarine compartment and freshwater, particularly at the rainy season, due to washout effects of carbonaceous soils and different organic anthropogenic effluents. The estuary served as a source of DIC to the atmosphere with an estimated flux of 13 mol CO₂ m^?2 year^?1. Input from the river was 46 mol CO₂ m^?2 year^?1. The metabolism of the system was heterotrophic, but short periods of autotrophy occurred in the lower more marine portions of the estuary. The pelagic system was more or less balanced between auto- and heterotrophy, whereas the benthic and intertidal mangrove region was heterotrophic. Estimated annual NEM yielded a total DIC production in the order of 18 mol CO₂ m^?2 year^?1. The anthropogenic inputs of particulate C, N, and P, dissolved inorganic P (DIP), and DIC were significant. The fluvial loading of particulate organic carbon and dissolved inorganic nitrogen (DIN) was largely retained in two flow regulation and hydroelectric reservoirs, promoting a reduction of C:N and C:P particulate ratios in the estuary. The net nonconservative fluxes obtained by a mass balance approach revealed that the estuary acts as a source of DIP, DIN, and DIC, the latter one being almost equivalent to the losses to the atmosphere. Mangrove forests and tidal mudflats were responsible for most of NEM rates and are the main sites of organic decomposition to sustain net heterotrophy. The main sources for this organic matter are the fluvial and anthropogenic inputs. The mangrove areas are the highest estuarine sources of DIP, DIC, and DIN.  相似文献   

激光剥蚀-等离子体质谱技术及其在地球化学宇宙化学和环境研究中的应用   总被引：1，自引：0，他引：1  

JOCHUM Klaus Peter  STOLL Brigitte  FRIEDRICH Jon M  AMINI Marghaleray  BECKER Stefan  DüCKING Marc  EBEL Denton S  ENZWEILER Jacinta  胡明月  KUZMIN Dmitry  MERTZ KRAUS Regina  MüLLER Werner E G  REGNERY Julia  SOBOLEV Alexander  王晓红  詹秀春 《岩矿测试》2009,28(1):53-68

激光剥蚀-等离子体质谱(LA-ICPMS)已成为地球化学、宇宙化学和环境研究领域元素和同位素原位分析最重要的技术之一。文章介绍了多种类型的质谱仪及其使用的激光器。用途最广的LA-ICPMS仪器之一是单接收器扇形磁场质谱仪,配有Nd:YAG激光剥蚀系统(激光波长分为193 nm和213 nm两种),MPI Mainz实验室使用的就是这套系统,文章对此作一详细介绍。文中阐述了数据优化技术及其多种校正过程;介绍LA-ICPMS在痕量元素和同位素分析领域的一些应用,包括参考物质的研制,Hawaiian玄武岩、Martian陨石、生物骨针和珊瑚虫中痕量元素分析及熔融包裹体和富钙-铝碳质球粒陨石中的铅和锶同位素测量。  相似文献   

Understanding Causes of Conflict Over Common Village Pastures – A Comparative Analysis of Property Rights in Azerbaijan and Georgia     

Regina Neudert  Insa Theesfeld  Alexandre Didebulidze  Naiba Allahverdiyeva  Volker Beckmann 《社会与自然资源》2020,33(3):347-367

Abstract

Conflicts in the management of renewable natural resources are situations in which actors have diverging opinions on issues of natural resource use. In the literature, among the causal factors for conflicts discussed are resource wealth or scarcity and the role of governance. The evidence, however, is contradictory. In order to analyze the role of governance in more detail, we propose a combined analysis of property rights and conflicts. In this way, an improved understanding of the causes of local conflicts over renewable natural resources can be achieved. We use comparative case study data from pasture management in the Caucasus region, first, to classify conflicts according to the bundle of property rights approach and, second, to explore how the causal factors resource scarcity and current governance contribute to those conflicts.  相似文献   

Foraging behaviour,swimming performance and malformations of early stages of commercially important fishes under ocean acidification and warming     

Marta S. Pimentel  Filipa Faleiro  Tiago Marques  Regina Bispo  Gisela Dionísio  Ana M. Faria  Jorge Machado  Myron A. Peck  Hans Pörtner  Pedro Pousão-Ferreira  Emanuel J. Gonçalves  Rui Rosa 《Climatic change》2016,136(3-4):495-505

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Relative equilibria of the restricted three-body problem in curved spaces     

Regina Martínez  Carles Simó 《Celestial Mechanics and Dynamical Astronomy》2017,128(2-3):221-259

We use a formulation of the N-body problem in spaces of constant Gaussian curvature, \({\kappa }\in \mathbb {R}\), as widely used by A. Borisov, F. Diacu and their coworkers. We consider the restricted three-body problem in \(\mathbb {S}^2\) with arbitrary \({\kappa }>0\) (resp. \(\mathbb {H}^2\) with arbitrary \({\kappa }<0\)) in a formulation also valid for the case \({\kappa }=0\). For concreteness when \({\kappa }>0\) we restrict the study to the case of the three bodies at the upper hemisphere, to be denoted as \(\mathbb {S}^2_+\). The main goal is to obtain the totality of relative equilibria as depending on the parameters \({\kappa }\) and the mass ratio \(\mu \). Several general results concerning relative equilibria and its stability properties are proved analytically. The study is completed numerically using continuation from the \({\kappa }=0\) case and from other limit cases. In particular both bifurcations and spectral stability are also studied. The \(\mathbb {H}^2\) case is similar, in some sense, to the planar one, but in the \(\mathbb {S}^2_+\) case many differences have been found. Some surprising phenomena, like the coexistence of many triangular-like solutions for some values \(({\kappa },\mu )\) and many stability changes will be discussed.  相似文献   

Fluorescence as a Tool for Tracing the Organic Contamination from Pulp Mill Effluents in Surface Waters     

Eduarda B. H. Santos  Olga M. S. Filipe  Regina M. B. O. Duarte  Helena Pinto  Armando C. Duarte 《洁净——土壤、空气、水》2001,28(7):364-371

Three‐dimensional fluorescence spectra of water samples from an eucalyptus bleached kraft pulp mill and from a river, upstream and downstream of the discharge of the effluent, revealed the existence of a peak at δ_exc = 280 nm and δ_em = 340 nm Δδ = 60 nm), characteristic of effluentπs organic matter. Humic substances were isolated from the effluent by sequential adsorption onto resins XAD‐8 and XAD‐4 in series. Their synchronous fluorescence spectra with Δδ = 60 nm do also exhibit an intense signal at δ_exc = 280 nm (≈ 300 nm in the humic acid fraction). The peak is absent in the spectra of humic substances isolated from a non‐polluted site of the river, but it is clearly seen in the spectra of the humic substances from a site downstream of the discharge of the effluent. Synchronous fluorescence spectra (Δδ = 60 nm) of water samples from the river and its lagoon were recorded and revealed to be an easy and fast way of tracing the organic contamination from the effluent.  相似文献   

Modelling the dust and gas outflows from IRC+10 216 -- I. Ground-based and airborne observations     

C. J. Skinner †  K. Justtanont ‡  A. G. G. M. Tielens  A. L. Betz  R. T. Boreiko  F. Baas 《Monthly notices of the Royal Astronomical Society》1999,302(2):293-304

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Quantifying the degradation of an oil layer on the sea surface     

Michael Betz 《Marine environmental research》1983,10(1):59-61

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