Evaluation of High-Frequency Mean Streamwater Transit-Time Estimates Using Groundwater Age and Dissolved Silica Concentrations in a Small Forested Watershed     

Norman E. Peters  Douglas A. Burns  Brent T. Aulenbach 《Aquatic Geochemistry》2014,20(2-3):183-202

Many previous investigations of mean streamwater transit times (MTT) have been limited by an inability to quantify the MTT dynamics. Here, we draw on (1) a linear relation (r ² = 0.97) between groundwater ³H/³He ages and dissolved silica (Si) concentrations, combined with (2) predicted streamwater Si concentrations from a multiple-regression relation (R ² = 0.87) to estimate MTT at 5-min intervals for a 23-year time series of streamflow [water year (WY) 1986 through 2008] at the Panola Mountain Research Watershed, Georgia. The time-based average MTT derived from the 5-min data was ~8.4 ± 2.9 years and the volume-weighted (VW) MTT was ~4.7 years for the study period, reflecting the importance of younger runoff water during high flow. The 5-min MTTs are normally distributed and ranged from 0 to 15 years. Monthly VW MTTs averaged 7.0 ± 3.3 years and ranged from 4 to 6 years during winter and 8–10 years during summer. The annual VW MTTs averaged 5.6 ± 2.0 years and ranged from ~5 years during wet years (2003 and 2005) to >10 years during dry years (2002 and 2008). Stormflows are composed of much younger water than baseflows, and although stormflow only occurs ~17 % of the time, this runoff fraction contributed 39 % of the runoff during the 23-year study period. Combining the 23-year VW MTT (including stormflow) with the annual average baseflow for the period (~212 mm) indicates that active groundwater storage is ~1,000 mm. However, the groundwater storage ranged from 1,040 to 1,950 mm using WY baseflow and WY VW MTT. The approach described herein may be applicable to other watersheds underlain by granitoid bedrock, where weathering is the dominant control on Si concentrations in soils, groundwater, and streamwater.  相似文献   

Book review     

Douglas C. Peters 《Mathematical Geosciences》1991,23(5):793-794

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小型激光天文动力学空间计划概念   总被引：1，自引：0，他引：1  

倪维斗  朱进  武向平  褚桂柏  杨彬  高健  关敏  汤健仁  周翊  张中豪  黄天衣  曲钦岳  易照华  李广宇  陶金河  吴岸明  罗俊  叶贤基  周泽兵  熊耀恒  毕少兰  须重明  吴雪君  唐孟希  包芸  李芳昱  黄珹  杨福民  叶叔华  张书练  张元仲  聂玉昕  陈光  Joergen Christensen-Dalsgaard  Hansjoerg Dittus  Yasunori Fujii  Claus Laemmerzahl  Jean Francois Mangin  Achim Peters  Albrecht Ruediger  Etienne Samain  Stephan Schiller 《天文研究与技术》2002,(3):123-136

小型激光天文动力学空间计划是 :使用在太阳轨道上无拖曳航天器和地面站以激光干涉和脉冲测距的方法 ,精确地探讨天文动力学 ,检测相对论与时空基本定律 ,改进探测引力波的灵敏度以及更准确地测定太阳、行星和小行星的参数。 1 969年开始的月球激光 (反射 )测距 ,对地球物理、参考坐标的选定、相对论的检验均有重要的贡献。 3 0年来 ,激光技术的长足进步 ,使现在正是适合于开始进行研究空间有源 (主动 )测距和光波空间通讯的时候。激光天文动力学的兴起是必然的趋势 ,其精确度将比现在提高 3到 6个数量级 ,将是天文动力学革命性的发展。小型激光天文动力学空间计划可以起到带头作用。它的关键技术有三 ,即 :弱光锁相、极精确无拖曳航天和高衰减日冕仪。弱光锁相已有长足的进步。对高衰减日冕仪的研究 ,也有了初步的方案。LISA空间计划将于 2 0 0 6年 8月发射SMART -2 ,研究测试极精确无拖曳航天。小型激光天文动力学空间计划的关键技术已日趋成熟。在第一届国际激光天文动力学研讨会 ( 2 0 0 1 ,9.1 3 -2 3 )中介绍了各相关学科背景及前沿研究 ,讨论了激光天文动力学空间计划科学目标及相关技术 ,并召开了两次小型激光天文动力学空间计划预研究筹备会 ,建立了和欧洲的合作关系。会后着手进行此项对基础  相似文献   

Thermal expansion of gehlenite, Ca2Al[AlSiO7], and the related aluminates LnCaAl[Al2O7] with Ln=Tb, Sm     

L. Peters  K. Knorr  M. Knapp  W. Depmeier 《Physics and Chemistry of Minerals》2005,32(7):460-465

The thermal expansion of gehlenite, Ca₂Al[AlSiO₇], (up to T=830 K), TbCaAl[Al₂O₇] (up to T=1,100 K) and SmCaAl[Al₂O₇] (up to T=1,024 K) has been determined. All compounds are of the melilite structure type with space group Thermal expansion data was obtained from in situ X-ray powder diffraction experiments in-house and at HASYLAB at the Deutsches Elektronen Synchrotron (DESY) in Hamburg (Germany). The thermal expansion coefficients for gehlenite were found to be: α₁=7.2(4)×10⁻⁶ K⁻¹+3.6(7)×10⁻⁹ΔT K⁻² and α₃=15.0(1)×10⁻⁶ K⁻¹. For TbCaAl[Al₂O₇] the respective values are: α₁=7.0(2)×10⁻⁶ K⁻¹+2.0(2)×10⁻⁹ΔT K⁻² and α₃=8.5(2)×10⁻⁶ K⁻¹+2.0(3)×10⁻⁹ΔT K⁻², and the thermal expansion coefficients for SmCaAl[Al₂O₇] are: α₁=6.9(2)× 10⁻⁶ K⁻¹+1.7(2)×10⁻⁹ΔT K⁻² and α₃=9.344(5)×10⁻⁶ K⁻¹. The expansion-mechanisms of the three compounds are explained in terms of structural trends obtained from Rietveld refinements of the crystal structures of the compounds against the powder diffraction patterns. No structural phase transitions have been observed. While gehlenite behaves like a ’proper’ layer structure, the aluminates show increased framework structure behaviour. This is most probably explained by stronger coulombic interactions between the tetrahedral conformation and the layer-bridging cations due to the coupled substitution (Ca²⁺+Si⁴⁺)-(Ln ³⁺+Al³⁺) in the melilite-type structure. Electronic Supplementary Material Supplementary material is available for this article at  相似文献   

Post-Kyoto greenhouse gas inventories: production versus consumption   总被引：8，自引：0，他引：8  

Glen P. Peters  Edgar G. Hertwich 《Climatic change》2008,86(1-2):51-66

For the long-term stabilization of greenhouse gas (GHG) concentrations it is important that post-Kyoto policy has broad participation to ensure environmental integrity. Many post-Kyoto frameworks have been debated, but surprisingly approaches that focus on consumption have received little attention in the climate change literature despite broader interest in other areas. In this article we extend the argument for constructing GHG inventories using a country’s consumption rather than production. First, we argue that constructing GHG inventories using a country’s economic activity instead of geographic territory solves allocation issues for international activities such as international transportation and carbon capture and storage. Second, we argue that consumption-based GHG inventories have many advantages over production-based inventories. The main advantages are to address carbon leakage, reduce the importance of emission commitments for developing countries, increase options for mitigation, encourage environmental comparative advantage, address competitiveness concerns, and naturally encourage technology diffusion.  相似文献   

Particle transport and distribution on the Mars Science Laboratory mission: Effects of triboelectric charging     

Robert C. Anderson  Gregory H. Peters  Louise Jandura  Kenneth Manatt  Erik Pounders  Dan Sunshine 《Icarus》2009,204(2):545-7971

We report on the nature of fine particle (<150 μm) transport under simulated martian conditions, in order to better understand the Mars Science Laboratory’s (MSL) sample acquisition, processing and handling subsystem (SA/SPaH). We find that triboelectric charging due to particle movement may have to be controlled in order for successful transport of fines that are created within the drill, processed through the Collection and Handling for In situ Martian Rock Analysis (CHIMRA) sample handing system, and delivered to the Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments. These fines will be transferred from the surface material to the portioner, a 3 mm diameter, 8 mm deep distribution center where they will drop ∼2 cm to the instrument inlet funnels. In our experiments, movement of different material including terrestrial analogs and martian soil simulants (Mars Mojave Simulant - MMS) resulted in 1-7 nanocoulombs of charge to build up for several different experimental configurations. When this charging phenomenon occurs, several different results are observed including particle clumping, adherence of material on conductive surfaces, or electrostatic repulsion, which causes like-charged particles to move away from each other. This electrostatic repulsion can sort samples based upon differing size fractions, while adhesion causes particles of different sizes to bind into clods. Identifying these electrostatic effects can help us understand potential bias in the analytical instruments and to define the best operational protocols to collect samples on the surface of Mars.  相似文献   

Sediment cascades and the entangled relationship between human impact and natural dynamics at the pre-pottery Neolithic site of Göbekli Tepe,Anatolia     

Moritz Nykamp  Fabian Becker  Ricarda Braun  Nadja Pöllath  Daniel Knitter  Joris Peters  Brigitta Schütt 《地球表面变化过程与地形》2021,46(2):430-442

This study presents a meta-analysis of radiocarbon ages for the environs of Göbekli Tepe – one of the oldest monumental structures worldwide – using cumulative probability functions to diachronically assess phases of geomorphodynamic activity as controlled by natural or anthropogenic drivers. We employ sediment cascades as a heuristic framework to study the complex responses of the geomorphological system to various triggers at local to supra-regional scales. Possible triggers include climatic variability as documented by supra-regional hydroclimatic proxy data, regional demographic trends, and local to regional socioeconomic developments such as the emergence of sedentism or the introduction and dispersal of livestock herding. Our results show that phases of intensified geomorphodynamic activity occurred between ca. 7.4–7.0 and 5.8–3.3 ka BP. These phases roughly coincide with phases of population growth in southern Turkey and climatic variations in Turkey and the Levant. The phase between ca. 5.8–3.3 ka BP also corresponds to the time when organized agriculture and the seeder plough were introduced. Also, the identified phases are in agreement with the general trend of varying geomorphodynamic activity in the Eastern Mediterranean as driven by human impact and climatic change. However, neither the Younger Dryas–Holocene transition nor the development of herding during the Pre-Pottery Neolithic left a clear signature. We demonstrate how the different depositional environments in the studied landscape compartments vary with respect to their spatiotemporal coverage and discuss challenges when trying to understand processes that once shaped landscapes of past societies. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd  相似文献   

Mass physical properties, sliding and erodibility of experimentally deposited and differently consolidated clayey muds (Approach, equipment, and first results)     

G. EINSELE  R. OVERBECK  H. U. SCHWARZ  G. UNSÖLD 《Sedimentology》1974,21(3):339-372

On experimentally deposited kaolinite, illite, and Ca-bentonite consolidated under their own load or by additional vertical pressure, the progress of compaction in relation to excess pore water pressure, mass physical properties, gravitational mass movements in a tilted tank, and erodibility under running water in a flume were studied. The very low consolidated sediments near the mud/water interface do not obey the generally used theory in soil mechanics. They show a different, non-linear relationship between void ratio or water content and depth below the sedimentary surface on the one hand, or effective overburden pressure and shear strength on the other. The same is true of other physical properties such as permeability, which changes considerably with depth and time of consolidation. High sedimentation rates on slopes induce shallow sediment flow, whereas at low rates and critical slope angles different types of slope failures including the breaking up of water-rich sediment into sharp boundered blocks are observed. Flume studies on soft clay muds show three different types of erosion: continuously suspending, discontinuous erosion of crumbs or shreds, and wavy deformation of the clay surface with disintegration of particles from the crests. The critical tractive stress depends not only on clay type, void ratio, and shear strength, but significantly also on the ‘geologic history’of the clay (i.e. deposition from thin suspension or dense slurry, fabric, consolidation and swelling generating minute inhomogeneities etc.). The experiments may lead to a better understanding of all mechanical processe's including pore-water flow taking place near or not far below the sediment/ water interface.  相似文献   

Trends of the EU’s territorial and consumption-based emissions from 1990 to 2016     

Jonas Karstensen  Glen P. Peters  Robbie M. Andrew 《Climatic change》2018,149(2):131-145

In this paper, a model for the distribution of the Global Carbon Budget between the countries of the world is presented. The model is based on the criteria of equity while also taking into account the different historical responsibilities. The Global Carbon Budget corresponds to the quantity of carbon dioxide emissions that can still be released into the atmosphere while maintaining the increase in the average earth surface temperature below 2 °C, and it is therefore compatible with the long-term objective defined in the Paris Agreement. The results of applying the model are shown both for the 15 emitters that currently top the ranking for world emissions as well as for the other countries, which are grouped together in three main groups: Other African, Other Latin American and Caribbean, and the Rest of the World. Mitigation curves compatible with the carbon budget allocated to the different countries are presented. When comparing each emitter’s historical emissions for the period 1971–2010 with the proposed distribution for the period 2011–2050 obtained using the model, it can be seen that developed countries must face the future with a greatly reduced carbon budget, whereas developing countries can make use of a carbon budget that is higher than their cumulative historical emissions. Finally, there is a discussion about how a model with these characteristics could be useful when implementing the Paris Agreement.  相似文献   

First Results of Measurements with a Newly-Designed Phased-Array Sodar with RASS     

D. Engelbart  H. Steinhagen  U. Görsdorf  J. Neisser  H. J. Kirtzel  G. Peters 《Meteorology and Atmospheric Physics》1999,71(1-2):61-68

Summary At a special measuring site for boundary-layer studies as well as land-surface processes the Meteorological Observatory Lindenberg of the German Weather Service (DWD) has recently put into operation a newly-desi gned phased-array SODAR/RASS, which has been developed by METEK on behalf of the DWD. This system provides the vertical profiles of the three-di mensional wind vector in the boundary layer on an operational basis and is furthermore suitable for getting information on the profile of virtual temperature up to about 400 m in height based on the addition of RASS components. The following paper describes both the technique of this SODAR/RASS and the various modes of operation as well as the different options in managing the system. First evaluations on the data availability concerning the maximum height coverage will give an impression on the system’s capabilities. Finally, the accuracy of the derived profiles of winds and temperature will be investigated by means of comparisons of the SODAR/RASS data with measurements of a six-sonde tethered-balloon system as well as meteorological data of a 99 m tower in the vicinity of the system. Received November 27, 1998 Revised April 9, 1999  相似文献