USGS46 Greenland Ice Core Water – A New Isotopic Reference Material for δ2H and δ18O Measurements of Water     

Tyler B. Coplen  Haiping Qi  Lauren Tarbox  Jennifer Lorenz  Bryan Buck 《Geostandards and Geoanalytical Research》2014,38(2):153-157

Ice core from Greenland was melted, filtered, homogenised, loaded into glass ampoules, sealed, autoclaved to eliminate biological activity, and calibrated by dual‐inlet isotope‐ratio mass spectrometry. This isotopic reference material (RM), USGS46, is intended as one of two secondary isotopic reference waters for daily normalisation of stable hydrogen (δ²H) and stable oxygen (δ¹⁸O) isotopic analysis of water with a mass spectrometer or a laser absorption spectrometer. The measured δ²H and δ¹⁸O values of this reference water were ?235.8 ± 0.7‰ and ?29.80 ± 0.03‰, respectively, relative to VSMOW on scales normalised such that the δ²H and δ¹⁸O values of SLAP reference water are, respectively, ?428 and ?55.5‰. Each uncertainty is an estimated expanded uncertainty (U = 2u_c) about the reference value that provides an interval that has about a 95‐percent probability of encompassing the true value. This reference water is available in cases containing 144 glass ampoules that are filled with either 4 ml or 5 ml of water per ampoule.  相似文献   

Lessons from co-impacts assessment under the Mitigation Action Plans and Scenarios (MAPS) Programme     

Brett Cohen  Emily Tyler  Marta Torres Gunfaus 《Climate Policy》2013,13(8):1065-1075

The MAPS Programme has been active in Brazil, Chile, Colombia and Peru in supporting the development of an evidence base to inform the processes involved in climate mitigation policy-making. The programme combines detailed quantitative analysis with an extensive stakeholder engagement process to provide policy and decision makers with the information required for long-term climate mitigation planning.

In recognition of the critical need to consider the developmental context and agenda in climate policy-making, the projects undertaken in these countries have experimented with various types of assessments of developmental impacts at both the macro and micro levels. These impacts have been collectively termed co-impacts to reflect the fact that these may be either positive or negative. In this article the value and challenges associated with co-impacts work for climate mitigation policy are considered. The value of including co-impacts analysis in the MAPS processes included increased stakeholder buy-in, making the case for mitigation action, informing INDCs and the prioritization of particular mitigation actions. Challenges include those associated with obtaining locally relevant data, the selection and operation of appropriate macro-economic models and analytical approaches and working with multidisciplinary teams.

The article concludes by making some suggestions to optimize co-impacts work, through reference to other bodies of literature. The authors highlight that this article is situated within a dominant approach to climate mitigation policy work in developing countries, which implicitly places the non-climate benefits of any action as secondary to the primary benefit of climate change mitigation and constructs an artificial separation of policy formulation and implementation. Practitioners are encouraged to reflect on the implications of these considerations in future efforts.

Policy relevance

One of the primary challenges to advancing climate mitigation policy in developing countries is that of perceived relevance: near-term development priorities are overwhelming. Identifying, understanding and engaging with the co-impacts of mitigation actions has emerged as one way of addressing this challenge. Although still at an experimental phase, experience with co-impacts analysis in the MAPS countries provides some useful lessons in how to develop this area of work.  相似文献   

Combining price and quantity instruments: insights from South Africa     

Emily Tyler  Brent Cloete 《Climate Policy》2013,13(3):374-387

A carbon tax will form the central carbon pricing instrument in South Africa. The country, however, is also in the process of setting specific short-term emissions limits at a subnational level. Additional mitigation policy instruments will thus be required to meet these targets. Although it is possible to combine sector-level quantity targets with a broad-based carbon tax, this article finds that this greatly complicates mitigation policy design, increasing both the information requirements and the likelihood of unintended consequences. The trade-offs between economic efficiency (optimized by the use of a broad-based price set by a carbon tax) and environmental effectiveness (optimized by using instruments that ensure emissions reduction targets are met) are ever present. A clear understanding of subnational quantity targets and an appreciation of the characteristics of the instruments to achieve such targets (quantity-based instruments, QBIs), the framework through which the instruments are combined, and their possible interactions, are required for effective policy making. Three possible frameworks for combining instruments are identified in the article, and some specific implications of interaction between particular QBIs and a carbon tax are suggested.

Policy relevance

This article explores the interaction of a carbon tax with mitigation policy instruments to meet subnational emissions targets in the South African context (where both a carbon tax and subnational emissions targets are currently being developed). As international negotiations progress towards countries accepting binding GHG emissions restrictions, quantity-based mitigation policy approaches become more important. In countries where a broad-based emissions trading scheme (ETS) is not feasible in the short to medium term, combining a broad-based carbon tax with subnational emission targets provides an alternative mechanism for achieving the economic efficiency and emissions certainty benefits derived from an ETS. This paper considers the mechanisms through which such a combination of instruments can be achieved. Three possible frameworks for combining instruments are identified, some specific implications of interaction between particular QBIs and a carbon tax are suggested, and guidelines and concept tools are presented to assist policy-makers in designing efficient and coherent mitigation policy.  相似文献   

Hydrothermal faunal assemblages and habitat characterisation at the Eiffel Tower edifice (Lucky Strike,Mid‐Atlantic Ridge)     

Daphne Cuvelier  Pierre‐Marie Sarradin  Jozée Sarrazin  Ana Colaço  Jon T. Copley  Daniel Desbruyères  Adrian G. Glover  Ricardo Serrão Santos  Paul A. Tyler 《Marine Ecology》2011,32(2):243-255

The Eiffel Tower edifice is situated in the Lucky Strike hydrothermal vent field at a mean depth of 1690 m on the Mid‐Atlantic Ridge (MAR). At this 11‐m‐high hydrothermal structure, different faunal assemblages, varying in visibly dominant species (mussels and shrimp), in mussel size and in density of mussel coverage, were sampled biologically and chemically. Temperature and sulphide (∑S) were measured on the different types of mussel‐based assemblages and on a shrimp‐dominated assemblage. Temperature was used as a proxy for calculating total concentrations of CH₄. Based on the physico‐chemical measurements, two microhabitats were identified, corresponding to (i) a more variable habitat featuring the greatest fluctuations in environmental variables and (ii) a second, more stable, habitat. The highest temperature variability and the highest maximum recorded temperatures were found in the assemblages visibly inhabited by alvinocaridid shrimp and dense mussel beds of large Bathymodiolus azoricus, whereas the less variable habitats were inhabited by smaller‐sized mussels with increasing bare surface in between. Larger mussels appeared to consume more ∑S compared with smaller‐sized (<1 cm) individuals and thus had a greater influence on the local chemistry. In addition, the mussel size was shown to be significantly positively correlated to temperature and negatively to the richness of the associated macrofauna. The presence of microbial mats was not linked to specific environmental conditions, but had a negative effect on the presence and abundance of macro‐fauna, notably gastropods. Whereas some taxa or species are found in only one of the two microhabitats, others, such as polychaetes and Mirocaris shrimp, cross the different microhabitats. Temperature was proposed to be a more limiting factor in species distribution than ∑S.  相似文献   

Grain size distributions and photoelectric heating in ionized media     

P. A. M. van Hoof †  J. C. Weingartner ‡  P. G. Martin  K. Volk §  G. J. Ferland 《Monthly notices of the Royal Astronomical Society》2004,350(4):1330-1341

  相似文献   

Landslide susceptibility analysis based on citizen reports     

Tyler J. Rohan  Nicholas Wondolowski  Eitan Shelef 《地球表面变化过程与地形》2021,46(4):791-803

Landslide susceptibility estimates are essential for reducing the risk posed by landslides to social and economic well-being. However, estimates of landslide susceptibility depend on reliable landslide inventories whose production requires extensive field or remote sensing efforts. Further, most inventories are not updated through time and thus may not capture the influence of changes in climate and/or land use. Inventories based on citizen reports of landslide occurrence, have the potential to overcome these limitations. Such an inventory can be produced from citizen reports to a 311-phone and online system, a nationwide database that updates real-time and records reported landslides location and timing. Whereas this landslide inventory is promising, it has not used for landslide susceptibility analyses and may be associated with spatial uncertainties and reporting biases. In this study we explore the use of 311-based landslide inventory for landslide susceptibility estimates in Pittsburgh, PA, USA, where landslide risk is among the highest in the nation. We compare the 311-based inventory to field-validated inventories through a multi-pronged approach that combines field validation of 311-reported landslides, probabilistic analysis of the association between landslides and the underlying topographic and geologic factors, and spatial filtering. Our results show that: (a) approximately 70% of the 311-reported landslides are associated with an identifiable landslide in the field; (b) the spatial uncertainty of the 311-reported landslides is 104 ± 25 m; (c) 311-reported landslides differ from other inventories in that they are primarily associated with proximity to roads, however, field-correction of 311-reported landslide locations rectifies this anomaly; (d) a simple spatial filter, scaled by the uncertainty in location as determined from a subset of the 311-data, can increase the consistency between the 311-reported inventory and field-validated inventories. These results suggest that 311-based landslide inventories can improve susceptibility estimates at a relatively low cost and high temporal resolution.  相似文献   

Late Quaternary dietary shifts of the Cape grysbok (Raphicerus melanotis) in southern Africa     

J. Tyler Faith 《Quaternary Research》2011,75(1):159-165

The Cape grysbok is endemic to southern Africa's Cape Floral Region where it selectively browses various species of dicotyledonous vegetation. Fossil evidence indicates that the grysbok persisted under glacial and interglacial conditions throughout the late Quaternary and inhabited a range of environments. This study employs mesowear analysis to reconstruct grysbok diets over time and in response to changing environments at Nelson Bay Cave, Die Kelders Cave 1, Klasies River Mouth, and Swartklip 1. Results indicate that the amount of grasses (monocots) versus leafy vegetation (dicots) included in the diet fluctuated over time and largely in agreement with changes in faunal community structure. The case for dietary flexibility is particularly clear at Nelson Bay Cave, where there is a significant trend from mixed feeding towards increased browsing from the late Pleistocene (~ 18,500 ¹⁴C yr BP) through the Holocene. Dietary shifts at Nelson Bay Cave are consistent with the hypothesis that declining grassland productivity is responsible for the terminal Pleistocene extinction of several large ungulates in southern Africa. Furthermore, the short-term dietary shifts demonstrated here (100s to 1000s of years) provide an important caution against relying on taxonomic uniformitarianism when reconstructing the dietary preferences of fossil ungulates, both extant and extinct.  相似文献   

Estuarine sediment deposition during wetland restoration: A GIS and remote sensing modeling approach     

Michelle Elizabeth Newcomer  Amber Jean Michael Kuss  Tyler Ketron  Alex Remar  Vivek Choksi  J. W. Skiles 《国际地球制图》2013,28(4):451-467

Restoration is currently underway in the industrial salt flats of San Francisco Bay, California. Remote sensing of suspended sediment concentration and other GIS predictor variables were used to model sediment deposition within recently restored ponds. Suspended sediment concentrations were calibrated to reflectance values from Landsat TM 5 and ASTER satellite image data using three statistical techniques—linear regression, multivariate regression, and Artificial Neural Network (ANN) regression. Multivariate and ANN regressions using ASTER proved to be the most accurate methods, yielding r² values of 0.88 and 0.87, respectively. Predictor variables such as sediment grain size and tidal frequency were used in the Marsh Sedimentation (MARSED) model for predicting deposition rates. MARSED results show a root mean square deviation (RMSD) of 66.8 mm (<1σ) between modeled and field observations. This model was applied to a pond breached in November 2010 and indicated that the pond will reach sediment equilibrium levels after 60 months of tidal inundation.  相似文献   

A numerical study of the string function using a primitive equation ocean model     

R. H. Tyler  R. Käse 《地球物理与天体物理流体动力学》2013,107(1-2):65-83

Abstract

We use results from a primitive-equation ocean numerical model (SCRUM) to test a theoretical 'string function' formulation put forward by Tyler and Käse in another article in this issue. The string function acts as a stream function for the large-scale potential energy flow under the combined beta and topographic effects. The model results verify that large-scale anomalies propagate along the string function contours with a speed correctly given by the cross-string gradient. For anomalies having a scale similar to the Rossby radius, material rates of change in the layer mass following the string velocity are balanced by material rates of change in relative vorticity following the flow velocity. It is shown that large-amplitude anomalies can be generated when wind stress is resonant with the string function configuration.  相似文献   

Hydrological and meteorological data from research catchments at the Marcell Experimental Forest,Minnesota, USA     

Stephen D. Sebestyen  Nina K. Lany  Daniel Tyler Roman  Jacob M. Burdick  Richard L. Kyllander  Elon Sandy Verry  Randall K. Kolka 《水文研究》2021,35(3):e14092

The Marcell Experimental Forest (MEF) in northern Minnesota, USA, with hydrological research and monitoring of peatland catchments in a low-topographic relief landscape, contrasts with the mountainous terrain that typifies most research catchments. Six research catchments were instrumented and hydrological and meteorological monitoring was initiated during 1960. Paired-catchment studies, which started during 1969, have been used to assess land management and environmental change effects on forests, water availability, and biogeochemistry. Over the decades, the research and collaborations have proliferated to include new monitoring and ecosystem experiments. We provide an overview of available datasets and access information for hydrological and meteorological data. Data on streamflow, water table elevation, precipitation, snow, ground frost, air temperature, soil moisture, upland runoff, and water chemistry are discoverable with associated metadata and are archived through several Web-based, community repositories. The research programme is ongoing and we anticipate updates on an annual or more frequent basis. Additionally, we aim to release other physical, chemical, and isotopic measurements associated with long-term catchment monitoring and studies at the MEF.  相似文献