Leveraging correlation across space and time to interpolate geophysical data via CoKriging     

Sonja Pravilovic  Donato Malerba 《International journal of geographical information science》2018,32(1):191-212

Managing geophysical data generated by emerging spatiotemporal data sources (e.g. geosensor networks) presents a growing challenge to Geographic Information System science. The presence of correlation poses difficulties with respect to traditional spatial data analysis. This paper describes a novel spatiotemporal analytical scheme that allows us to yield a characterization of correlation in geophysical data along the spatial and temporal dimensions. We resort to a multivariate statistical model, namely CoKriging, in order to derive accurate spatiotemporal interpolation models. These predict unknown data by utilizing not only their own geosensor values at the same time, but also information from near past data. We use a window-based computation methodology that leverages the power of temporal correlation in a spatial modeling phase. This is done by also fitting the computed interpolation model to data which may change over time. In an assessment, using various geophysical data sets, we show that the presented algorithm is often able to deal with both spatial and temporal correlations. This helps to gain accuracy during the interpolation phase, compared to spatial and spatiotemporal competitors. Specifically, we evaluate the efficacy of the interpolation phase by using established machine-learning metrics (i.e. root mean squared error, Akaike information criterion and computation time).  相似文献   

Immuno-localisations (GSSP) of subcellular accumulation sites of phenanthrene, aroclor 1254 and lead (Pb) in relation to cytopathologies in the gills and digestive gland of the mussel Mytilus edulis     

Einsporn S  Koehler A 《Marine environmental research》2008,66(1):185-186

Cell and tissue pathology of both, gill and digestive tissue, has been the subject of many studies for the elucidation of contaminant-induced biological effects. In the present study, cellular pathological alterations were linked to subcellular sites of chemical accumulation in gills and digestive gland tissues. For this purpose, mussels (Mytilus edulis) were exposed to the organic contaminants aroclor 1254 (PCB) (20 microg/L), phenanthrene (PAH) (150 microg/L) or the metal lead (Pb) (2.5mg/L). The localization of chemicals at the subcellular level was analysed by an antibody-based detection system (GSSP) by the use of commercially available antibodies specifically directed against the chemicals. Pathological changes were analysed in parallel in identical samples by transmission electron microscopy. After exposure to the different contaminants, cell organelles such as mitochondria, the endo-lysosomal system as well as endoplasmic reticulum showed clear evidence of chemically-induced alterations. Large numbers of crystalloid inclusions were found in mitochondria and in autophagic lysosomes as well as multi-lamellated whorls after PAH and aroclor exposure. Immunocytochemical detection of the chemicals showed their accumulation inside of various cell organelles such as lysosomes, mitochondria, and nuclei. Additionally, chemicals were localized in association to membranes, cilia and microvilli of gill and digestive gland cells. Furthermore, the chitinous rod and mucus secretions of gill epithelial cells were positively labelled for contaminants indicating their role in protection. Localization of contaminants by immuno-detection in combination with pathological diagnosis gives insights into the cellular targets of chemical attack.  相似文献   

Is global warming affecting cave temperatures? Experimental and model data from a paradigmatic case study     

David Domínguez-Villar  Sonja Lojen  Kristina Krklec  Andy Baker  Ian J. Fairchild 《Climate Dynamics》2015,45(3-4):569-581

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A spatial approach to baseline and leakage in CDM forest carbon sinks projects     

Michael Dutschke  Sonja Butzengeiger  Axel Michaelowa 《Climate Policy》2013,13(5):517-530

Abstract

Forestry projects under the Clean Development Mechanism (CDM) face specific challenges with regard to determination of a baseline for carbon sequestration. We propose a semi-standardized approach called PARAPIA for calculation of a baseline that is built on the concept of a reference area around the project area whose land-use characteristics determine the baseline scenario. The land-use shares in the reference area are checked at each verification. Baseline carbon stocks are then derived ex post using the average carbon content of each land-use type. The reference area is between five and ten times larger than the project area. To determine indirect effects (the so-called ‘leakage’), a political influence area such as province or state is assessed with regards to migration flows due to the project and related emissions.  相似文献   

Additionality revisited: guarding the integrity of market mechanisms under the Paris Agreement     

Axel Michaelowa  Wolfgang Obergassel  Sonja Butzengeiger 《Climate Policy》2013,13(10):1211-1224

ABSTRACT

The Paris Agreement requires mitigation contributions from all Parties. Therefore, the determination of additionality of activities under the market mechanisms of its Article 6 will need to be revisited. This paper provides recommendations on how to operationalize additionality under Article 6. We first review generic definitions of additionality and current approaches for testing of additionality before discussing under which conditions additionality testing of specific activities or policies is still necessary under the new context of the Paris Agreement, that is, in order to prevent increases of global emissions. We argue that the possibility of ‘hot air’ generation under nationally-determined contributions (NDCs) requires an independent check of the NDC’s ambition. If the NDC of the transferring country does contain ‘hot air’, or if the transferred emission reductions are not covered by the NDC, a dedicated additionality test should be required. While additionality tests of projects and programmes could continue to be done through investment analysis, for policy instruments new approaches are required. They should be differentiated according to type of policy instrument. For regulation, we suggest calculating the resulting pay-back period for technology users. If the regulation generates investments exceeding a payback period threshold, it could be deemed additional. Similarly, carbon pricing policies that generate a carbon price exceeding a threshold could qualify; for trading schemes an absence of over-allocation needs to be shown. The threshold should be differentiated according to country categories and rise over time.

Key policy insights

• Without additionality testing, market mechanisms under the Paris Agreements might lead to an international diffusion of ‘hot air’. To avoid this, an independent assessment of NDC ambition is in order. Otherwise, activities under the mechanisms need to undergo specific additionality tests.

• Additionality testing of projects and programmes should build on the experience developed under the Kyoto Protocol mechanisms.

• Bold approaches are needed for assessing additionality of policies. To avoid cumbersome assessment of all activities triggered by such policies, highly aggregated approaches are suggested, ranging from payback period thresholds for technologies mandated by regulation to minimum price levels triggered by carbon pricing policies. Over time, the stringency of threshold values should increase.

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A sediment record of trophic state change in an Arkansas (USA) reservoir     

Byron Winston  Sonja Hausmann  Jaime Escobar  William F. Kenney 《Journal of Paleolimnology》2014,51(3):393-403

Reservoir sediments are used cautiously in paleolimnological studies because of dating uncertainties, possible sediment disturbances and even concerns that indicators of trophic status may behave differently in reservoirs as opposed to natural lakes. We measured loss on ignition (LOI), carbon to nitrogen ratio (C:N), diatom abundance, total nitrogen (TN), total phosphorus (TP), TN:TP ratio, and carbon and nitrogen isotopes (δ¹³C and δ¹⁵N) in an 83-cm sediment core to track recent trophic status changes in Beaver Reservoir, Northwest Arkansas, USA. Measurements showed that LOI, TN, TP and diatom abundance increased significantly from the bottom to the top of the core (p < 0.001). The C:N ratio and δ¹³C indicated a predominantly algal source for organic matter in the sediments. Increases in TN and TP were positively correlated with human population growth (p < 0.01) and the TN:TP ratio recorded a shift from phosphorus to nitrogen limitation around 1990. This shift may have encouraged cyanobacterial growth that caused episodes of taste and odor problems in the reservoir. This study suggests that despite concerns about sediment dating and disturbance, reservoir sediments can provide valuable information on past water quality changes.  相似文献   

The climate sensitive zone along an altitudinal gradient in central Himalayan rivers: a useful concept to monitor climate change impacts in mountain regions     

Ram Devi Tachamo Shah  Subodh Sharma  Peter Haase  Sonja C. Jähnig  Steffen U. Pauls 《Climatic change》2015,132(2):265-278

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The disc evolution of V2051 Oph on decline from superoutburst     

Sonja Vrielmann  Warren Offutt 《Monthly notices of the Royal Astronomical Society》2003,338(1):165-175

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How hydrofractures become arrested     

Agust Gudmundsson  & Sonja L. Brenner 《地学学报》2001,13(6):456-462

Fluids in the earth's crust are commonly transported by hydrofractures, such as dykes and mineral veins, many of which become arrested at various crustal depths. Hydrofractures are commonly arrested – some showing blunt tips – at contacts between soft (low Young's modulus) and stiff (high Young's modulus) layers. For example, many dyke tips are arrested at contacts between soft pyroclastic rocks and stiff basaltic lava flows, and vein tips at contacts between soft marl and stiff limestone. Theoretical models indicate that overpressured, buoyant hydrofractures in homogeneous, isotropic host rocks should normally reach the surface. In layered host rocks, however, abrupt changes in Young's moduli, horizontal discontinuities, and layers with unusually high fracture-perpendicular stresses encourage hydrofracture arrest. It is proposed that for layer-parallel loading, stiff layers favour hydrofracture arrest during active compression but soft layers during extension. It is concluded that for hydrofracture propagation to occur, the stress field along its potential pathway must be essentially homogenous.  相似文献   

The scientific basis of marine pollution control     

Sonja Boehmer-Christiansen 《Marine Policy》1982,6(1):2-10

The author examines the scientific basis of the work of the Joint Group of Experts on the Scientific Aspects of Marine Pollution (GESAMP). Problems of definition and methodology are discussed, and the work of GESAMP working groups on, among others, Marine Waste Disposal, Coastal Water Quality Criteria and the Impact of Oil on the Marine Environment are reported. The author concludes that marine pollution control at the international level has not been able to make much practical headway because political expectations have outstripped scientific and administrative possibilities.  相似文献