Uncertainty,cost-effectiveness and environmental safety of robust carbon trading: integrated approach     

T. Ermolieva  Y. Ermoliev  M. Jonas  M. Obersteiner  F. Wagner  W. Winiwarter 《Climatic change》2014,124(3):633-646

Carbon markets, like other commodity markets, are volatile. They react to stochastic “disequilibrium” spot prices, which may be affected by inadequate policies, speculations and bubbles. The market-based emission trading, therefore, does not necessarily minimize abatement costs and achieve emission reduction goals. We introduce a basic stochastic model integrating emissions reduction, monitoring and trading costs allowing us to analyze the robustness of emission and uncertainty reduction policies under environmental safety constraints asymmetric information and other multiple anthropogenic and natural uncertainties. Explicit treatment of uncertainties provides incentives for reducing them before trading. We illustrate functioning of the robust market with numerical results involving such countries as the US, Australia, Canada, Japan, EU27, Russia, Ukraine. In particular, we analyze if the knowledge about uncertainties may affect portfolios of technological and trade policies or structure of the market and how uncertainty characteristics may affect market prices and change the market structure.  相似文献   

Evaluation of pan-Arctic melt-freeze onset in CMIP5 climate models and reanalyses using surface observations     

Jonas Mortin  Rune G. Graversen  Gunilla Svensson 《Climate Dynamics》2014,42(7-8):2239-2257

The seasonal melt-freeze transitions are fundamental features of the Arctic climate system. The representation of the pan-Arctic melt and freeze onset (north of 60°N) is assessed in two reanalyses and eleven CMIP5 global circulation models (GCMs). The seasonal melt-freeze transitions are retrieved from surface air temperature (SAT) across the land and sea-ice domains and evaluated against surface observations. While monthly averages of SAT are reasonably well represented in models, large model-observation and model–model disparities of timing of melt and freeze onset are evident. The evaluation against surface observations reveals that the ERA-Interim reanalysis performs the best, closely followed by some of the climate models. GCMs and reanalyses capture the seasonal melt-freeze transitions better in the central Arctic than in the marginal seas and across the land areas. The GCMs project that during the 21st century, the summer length—the period between melt and freeze onset—will increase over land by about 1 month at all latitudes, and over sea ice by 1 and 3 months at low and high latitudes, respectively. This larger summer-length increase over sea ice at progressively higher latitudes is related to a retreat of summer sea ice during the 21st century, since open water freezes roughly 40 days later than ice-covered ocean. As a consequence, by the year 2100, the freeze onset is projected to be initiated within roughly 10 days across the whole Arctic Ocean, whereas this transition varies by about 80 days today.  相似文献   

A Geographic Information System (GIS)-based approach for relating anthropogenic impact and environmental stress: a case study within the African Albertine Rift     

M.A. Jonas  J.C. Kostelnick 《国际地球制图》2013,28(8):707-732

This study introduces a potentially cost-effective methodology to assess habitat quality remotely using anthropogenic variables derived from both Geographic Information System (GIS) and remote sensing. We related anthropogenic impact to organism-level response across the Albertine Rift of East-Africa, which was measured using body condition (BC) in Lophuromys aquilus, the dark-coloured brush-furred rat. We chose seven variables to measure anthropogenic impact, ranging from land cover/land use to nighttime light radiance. Using a principal component analysis, we extracted four components that describe human impact and correlated each with BC. We documented that BC tended to be higher in more disturbed areas. We recommend this GIS-based methodology to relate anthropogenic impact to organismal-level response in the Albertine Rift region, and we provide broad guidelines for its application to assess habitat quality for species of conservation concern.  相似文献   

Effect of fluid pressure distribution on the structural evolution of accretionary wedges          下载免费PDF全文

Jonas B. Ruh 《地学学报》2017,29(3):202-210

Numerical experiments on evolving accretionary wedges usually implement predefined weak basal décollements and constant strength parameters for overlying compressed sequences, although fluid pressure ratio, and therefore brittle strength, can vary strongly in sedimentary basins. A two‐dimensional finite difference model with a visco‐elasto‐plastic rheology is used to investigate the influence of different simplified fluid pressure ratio distributions on the structural evolution of accretionary wedge systems. Results show that a linear increase in fluid pressure ratio towards the base leads to toeward‐verging thrust sheets and underplating of strata, while simulations with a predefined décollement form conjugate shear zones supporting box‐fold‐type frontal accretion. Surface tapers are in agreement with the critical wedge theory, which here is modified for cases of varying fluid pressure ratio. Furthermore, the numerical results resemble findings from natural examples of accretionary wedges.  相似文献   

Flare Prediction Using Photospheric and Coronal Image Data     

Eric Jonas  Monica Bobra  Vaishaal Shankar  J. Todd Hoeksema  Benjamin Recht 《Solar physics》2018,293(3):48

The precise physical process that triggers solar flares is not currently understood. Here we attempt to capture the signature of this mechanism in solar-image data of various wavelengths and use these signatures to predict flaring activity. We do this by developing an algorithm that i) automatically generates features in 5.5 TB of image data taken by the Solar Dynamics Observatory of the solar photosphere, chromosphere, transition region, and corona during the time period between May 2010 and May 2014, ii) combines these features with other features based on flaring history and a physical understanding of putative flaring processes, and iii) classifies these features to predict whether a solar active region will flare within a time period of \(T\) hours, where \(T = 2 \mbox{ and }24\). Such an approach may be useful since, at the present time, there are no physical models of flares available for real-time prediction. We find that when optimizing for the True Skill Score (TSS), photospheric vector-magnetic-field data combined with flaring history yields the best performance, and when optimizing for the area under the precision–recall curve, all of the data are helpful. Our model performance yields a TSS of \(0.84 \pm0.03\) and \(0.81 \pm0.03\) in the \(T = 2\)- and 24-hour cases, respectively, and a value of \(0.13 \pm0.07\) and \(0.43 \pm0.08\) for the area under the precision–recall curve in the \(T=2\)- and 24-hour cases, respectively. These relatively high scores are competitive with previous attempts at solar prediction, but our different methodology and extreme care in task design and experimental setup provide an independent confirmation of these results. Given the similar values of algorithm performance across various types of models reported in the literature, we conclude that we can expect a certain baseline predictive capacity using these data. We believe that this is the first attempt to predict solar flares using photospheric vector-magnetic field data as well as multiple wavelengths of image data from the chromosphere, transition region, and corona, and it points the way towards greater data integration across diverse sources in future work.  相似文献   

A model of diffuse Galactic radio emission from 10 MHz to 100 GHz     

Angélica de Oliveira-Costa  Max Tegmark  B. M. Gaensler  Justin Jonas  T. L. Landecker  Patricia Reich 《Monthly notices of the Royal Astronomical Society》2008,388(1):247-260

Understanding diffuse Galactic radio emission is interesting both in its own right and for minimizing foreground contamination of cosmological measurements. cosmic microwave background experiments have focused on frequencies ≳10 GHz, whereas 21-cm tomography of the high-redshift universe will mainly focus on ≲0.2 GHz, for which less is currently known about Galactic emission. Motivated by this, we present a global sky model derived from all publicly available total power large-area radio surveys, digitized with optical character recognition when necessary and compiled into a uniform format, as well as the new Villa Elisa data extending the 1.42-GHz map to the entire sky. We quantify statistical and systematic uncertainties in these surveys by comparing them with various global multifrequency model fits. We find that a principal component based model with only three components can fit the 11 most accurate data sets (at 10, 22, 45 and 408 MHz and 1.42, 2.326, 23, 33, 41, 61, 94 GHz) to an accuracy around 1–10 per cent depending on frequency and sky region. Both our data compilation and our software returning a predicted all-sky map at any frequency from 10 MHz to 100 GHz are publicly available at http://space.mit.edu/home/angelica/gsm .  相似文献   

A Variable Mesh Spacing for Large-Eddy Simulation Models in the Convective Boundary Layer     

Gervásio Annes Degrazia  Umberto Rizza  Franciano Scremin Puhales  Antônio Gledson Goulart  Jonas Carvalho  Guilherme Sausen Welter  Edson Pereira Marques Filho 《Boundary-Layer Meteorology》2009,131(2):277-292

A variable vertical mesh spacing for large-eddy simulation (LES) models in a convective boundary layer (CBL) is proposed. The argument is based on the fact that in the vertical direction the turbulence near the surface in a CBL is inhomogeneous and therefore the subfilter-scale effects depend on the relative location between the spectral peak of the vertical velocity and the filter cut-off wavelength. From the physical point of view, this lack of homogeneity makes the vertical mesh spacing the principal length scale and, as a consequence, the LES filter cut-off wavenumber is expressed in terms of this characteristic length scale. Assuming that the inertial subrange initial frequency is equal to the LES filter cut-off frequency and employing fitting expressions that describe the observed convective turbulent energy one-dimensional spectra, it is feasible to derive a relation to calculate the variable vertical mesh spacing. The incorporation of this variable vertical grid within a LES model shows that both the mean quantities (and their gradients) and the turbulent statistics quantities are well described near to the ground level, where the LES predictions are known to be a challenging task.  相似文献   

Comparison of preparatory signal analysis techniques for consideration in the (post-)Kyoto policy process   总被引：2，自引：2，他引：0  

Matthias Jonas  M. Gusti  W. Jęda  Z. Nahorski  S. Nilsson 《Climatic change》2010,103(1-2):175-213

Our study is a preparatory exercise. We focus on the analysis of uncertainty in greenhouse gas emission inventories. Inventory uncertainty is monitored, but not regulated, under the Kyoto Protocol to the United Nations Framework Convention on Climate Change. Under the Convention, countries publish annual or periodic national inventories of greenhouse gas emissions and removals. Policymakers use these inventories to develop strategies and policies for emission reductions and to track the progress of these policies. However, greenhouse gas inventories contain uncertainty for a variety of reasons, and these uncertainties have important scientific and policy implications. For most countries, the emission changes agreed under the Protocol are of the same order of magnitude as the uncertainty that underlies their combined (carbon dioxide equivalent) emissions estimates. Here we apply and compare six available techniques to analyze the uncertainty in the emission changes that countries agreed to realize by the end of the Protocol’s first commitment period 2008–2012. Any such technique, if implemented, could “make or break” claims of compliance, especially in cases where countries claim fulfillment of their commitments to reduce or limit emissions. The techniques all perform differently and can thus have a different impact on the design and execution of emission control policies. A thorough comparison of the techniques has not yet been made but is needed when expanding the discussion on how to go about dealing with uncertainty under the Kyoto Protocol and its successor.  相似文献   

Governance,complexity, and resilience   总被引：1，自引：0，他引：1  

Andreas Duit  Victor Galaz  Katarina Eckerberg  Jonas Ebbesson 《Global Environmental Change》2010,20(3):363-368

This special issue brings together prominent scholars to explore novel multilevel governance challenges posed by the behavior of dynamic and complex social-ecological systems. Here we expand and investigate the emerging notion of “resilience” as a perspective for understanding how societies can cope with, and develop from, disturbances and change. As the contributions to the special issue illustrate, resilience thinking in its current form contains substantial normative and conceptual difficulties for the analysis of social systems. However, a resilience approach to governance issues also shows a great deal of promise as it enables a more refined understanding of the dynamics of rapid, interlinked and multiscale change. This potential should not be underestimated as institutions and decision-makers try to deal with converging trends of global interconnectedness and increasing pressure on social-ecological systems.  相似文献   

From Discrete Gravity Survey Data to a High-resolution Gravity Field Representation in the Nordic-Baltic Region     

Silja Märdla  Jonas Ågren  Gabriel Strykowski  Tõnis Oja  Artu Ellmann  René Forsberg 《Marine Geodesy》2017,40(6):416-453

The deduction of a regularly spaced gravity anomaly grid from scattered survey data is studied, addressing mainly two aspects: reduction of gravity to anomalies and subsequent interpolation by various methods. The problem is illustrated in a heterogeneous study area and contrasting test areas including mountains, low terrains, and a marine area. Provided with realistic error estimates, Least Squares Collocation interpolation of Residual Terrain Model anomalies yields the highest quality gravity grid. In most cases, the Bouguer reduction and other interpolation methods tested are equally viable. However, spline-based interpolation should be avoided in marine areas with trackwise survey data.  相似文献