650 research outputs found
Uncertainty Quantification of Future Design Rainfall Depths in Korea
One of the most common ways to investigate changes in future rainfall extremes is to use future rainfall data simulated by climate models with climate change scenarios. However, the projected future design rainfall intensity varies greatly depending on which climate model is applied. In this study, future rainfall Intensity???Duration???Frequency (IDF) curves are projected using various combinations of climate models. Future Ensemble Average (FEA) is calculated using a total of 16 design rainfall intensity ensembles, and uncertainty of FEA is quantified using the coefficient of variation of ensembles. The FEA and its uncertainty vary widely depending on how the climate model combination is constructed, and the uncertainty of the FEA depends heavily on the inclusion of specific climate model combinations at each site. In other words, we found that unconditionally using many ensemble members did not help to reduce the uncertainty of future IDF curves. Finally, a method for constructing ensemble members that reduces the uncertainty of future IDF curves is proposed, which will contribute to minimizing confusion among policy makers in developing climate change adaptation policies
An Economic Analysis of Bushfires Management Programs
Allocating scare resources for fire management strategies requires information on the extent of economic losses from bushfires and the efficiency of alternatives. Despite the severity of bushfires, there is no agreed approach in Australia for estimating economic losses from fires nor for evaluating the economic efficiency of alternative suppression strategies. The poster proposes approaches to assess the economic effects of bushfires on local and state economies and sets out models to evaluate the economic efficiency of two key bushfire management strategies: presuppression and suppression. The first model arises from questions concerning the value of pre-suppression (before the fire) fuel reduction activities, and the estimation of an economically optimal fire management budget. The fuel reduction burning aims to reduce losses from a major fire event. To determine how the budget should be allocated, a modification of the Cost plus Net Value Change model is being used. This model has the advantage that each of the influencing parameters is easy to adjust or even change for different areas in Australia. The second model allows straightforward comparisons of approaches to bushfire suppression, through a fire simulation model. The simulation allows comparisons of alternative strategies under similar fire conditions. The economic utility in suppression of fire engines, dozers and aircraft is evaluated using Cost Benefit Analysis and a Cost plus Loss framework. The paper presents useful tools for decision makers to make damage assessment from fire, resource allocation on pre-suppression and guidelines for operational decision making on suppression approaches.Resource /Energy Economics and Policy, A11, H4, Q51, Q54,
Spectral Characteristic Evolution: A New Algorithm for Gravitational Wave Propagation
We present a spectral algorithm for solving the full nonlinear vacuum
Einstein field equations in the Bondi framework. Developed within the Spectral
Einstein Code (SpEC), we demonstrate spectral characteristic evolution as a
technical precursor to Cauchy Characteristic Extraction (CCE), a rigorous
method for obtaining gauge-invariant gravitational waveforms from existing and
future astrophysical simulations. We demonstrate the new algorithm's stability,
convergence, and agreement with existing evolution methods. We explain how an
innovative spectral approach enables a two orders of magnitude improvement in
computational efficiency.Comment: 28 pages, 9 figure
Valuing adaptation under rapid change
AbstractThe methods used to plan adaptation to climate change have been heavily influenced by scientific narratives of gradual change and economic narratives of marginal adjustments to that change. An investigation of the theoretical aspects of how the climate changes suggests that scientific narratives of climate change are socially constructed, biasing scientific narratives to descriptions of gradual as opposed rapid, non-linear change. Evidence of widespread step changes in recent climate records and in model projections of future climate is being overlooked because of this. Step-wise climate change has the potential to produce rapid increases in extreme events that can cross institutional, geographical and sectoral domains.Likewise, orthodox economics is not well suited to the deep uncertainty faced under climate change, requiring a multi-faceted approach to adaptation. The presence of tangible and intangible values range across five adaptation clusters: goods; services; capital assets and infrastructure; social assets and infrastructure; and natural assets and infrastructure. Standard economic methods have difficulty in giving adequate weight to the different types of values across these clusters. They also do not account well for the inter-connectedness of impacts and subsequent responses between agents in the economy. As a result, many highly-valued aspects of human and environmental capital are being overlooked.Recent extreme events are already pressuring areas of public policy, and national strategies for emergency response and disaster risk reduction are being developed as a consequence. However, the potential for an escalation of total damage costs due to rapid change requires a coordinated approach at the institutional level, involving all levels of government, the private sector and civil society.One of the largest risks of maladaptation is the potential for un-owned risks, as risks propagate across domains and responsibility for their management is poorly allocated between public and private interests, and between the roles of the individual and civil society. Economic strategies developed by the disaster community for disaster response and risk reduction provide a base to work from, but many gaps remain.We have developed a framework for valuing adaptation that has the following aspects: the valuation of impacts thus estimating values at risk, the evaluation of different adaptation options and strategies based on cost, and the valuation of benefits expressed as a combination of the benefits of avoided damages and a range of institutional values such as equity, justice, sustainability and profit.The choice of economic methods and tools used to assess adaptation depends largely on the ability to constrain uncertainty around problems (predictive uncertainty) and solutions (outcome uncertainty). Orthodox methods can be used where both are constrained, portfolio methodologies where problems are constrained and robust methodologies where solutions are constrained. Where both are unconstrained, process-based methods utilising innovation methods and adaptive management are most suitable. All methods should involve stakeholders where possible.Innovative processes methods that enable transformation will be required in some circumstances, to allow institutions, sectors and communities to prepare for anticipated major change.Please cite this report as: Jones, RN, Young, CK, Handmer, J, Keating, A, Mekala, GD, Sheehan, P 2013 Valuing adaptation under rapid change, National Climate Change Adaptation Research Facility, Gold Coast, pp. 192.The methods used to plan adaptation to climate change have been heavily influenced by scientific narratives of gradual change and economic narratives of marginal adjustments to that change. An investigation of the theoretical aspects of how the climate changes suggests that scientific narratives of climate change are socially constructed, biasing scientific narratives to descriptions of gradual as opposed rapid, non-linear change. Evidence of widespread step changes in recent climate records and in model projections of future climate is being overlooked because of this. Step-wise climate change has the potential to produce rapid increases in extreme events that can cross institutional, geographical and sectoral domains.Likewise, orthodox economics is not well suited to the deep uncertainty faced under climate change, requiring a multi-faceted approach to adaptation. The presence of tangible and intangible values range across five adaptation clusters: goods; services; capital assets and infrastructure; social assets and infrastructure; and natural assets and infrastructure. Standard economic methods have difficulty in giving adequate weight to the different types of values across these clusters. They also do not account well for the inter-connectedness of impacts and subsequent responses between agents in the economy. As a result, many highly-valued aspects of human and environmental capital are being overlooked.Recent extreme events are already pressuring areas of public policy, and national strategies for emergency response and disaster risk reduction are being developed as a consequence. However, the potential for an escalation of total damage costs due to rapid change requires a coordinated approach at the institutional level, involving all levels of government, the private sector and civil society.One of the largest risks of maladaptation is the potential for un-owned risks, as risks propagate across domains and responsibility for their management is poorly allocated between public and private interests, and between the roles of the individual and civil society. Economic strategies developed by the disaster community for disaster response and risk reduction provide a base to work from, but many gaps remain.We have developed a framework for valuing adaptation that has the following aspects: the valuation of impacts thus estimating values at risk, the evaluation of different adaptation options and strategies based on cost, and the valuation of benefits expressed as a combination of the benefits of avoided damages and a range of institutional values such as equity, justice, sustainability and profit.The choice of economic methods and tools used to assess adaptation depends largely on the ability to constrain uncertainty around problems (predictive uncertainty) and solutions (outcome uncertainty). Orthodox methods can be used where both are constrained, portfolio methodologies where problems are constrained and robust methodologies where solutions are constrained. Where both are unconstrained, process-based methods utilising innovation methods and adaptive management are most suitable. All methods should involve stakeholders where possible.Innovative processes methods that enable transformation will be required in some circumstances, to allow institutions, sectors and communities to prepare for anticipated major change
Spectral Cauchy Characteristic Extraction of strain, news and gravitational radiation flux
We present a new approach for the Cauchy-characteristic extraction of
gravitational radiation strain, news function, and the flux of the
energy-momentum, supermomentum and angular momentum associated with the
Bondi-Metzner-Sachs asymptotic symmetries. In Cauchy-characteristic extraction,
a characteristic evolution code takes numerical data on an inner worldtube
supplied by a Cauchy evolution code, and propagates it outwards to obtain the
space-time metric in a neighborhood of null infinity. The metric is first
determined in a scrambled form in terms of coordinates determined by the Cauchy
formalism. In prior treatments, the waveform is first extracted from this
metric and then transformed into an asymptotic inertial coordinate system. This
procedure provides the physically proper description of the waveform and the
radiated energy but it does not generalize to determine the flux of angular
momentum or supermomentum. Here we formulate and implement a new approach which
transforms the full metric into an asymptotic inertial frame and provides a
uniform treatment of all the radiation fluxes associated with the asymptotic
symmetries. Computations are performed and calibrated using the Spectral
Einstein Code (SpEC).Comment: 30 pages, 17 figure
Slow light with flat or offset band edges in multi-mode fiber with two gratings
We consider mode coupling in multimode optical fibers using either two Bragg
gratings or a Bragg grating and a long-period grating. We show that the
magnitude of the band edge curvature can be controlled leading to a flat,
quartic band-edge or to two band edges at distinct, nonequivalent -values,
allowing precise control of slow light propagation.Comment: 6 pages, 3 figure
Examining bushfire policy in action: Preparedness and behaviour in the 2009 Black Saturday fires
This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.An important part of reducing the risk of disaster is the preparedness of the people at risk. Australian bushfire authorities have policies and publicity about what households should do to be prepared - which include knowledge about fire risk, awareness of one's own risk, taking specific steps to reduce risk including having an emergency plan. Yet, there is sparse empirical evidence about the link between preparedness and actual behaviour in the face of a major disaster.The authors had an opportunity to examine the circumstances surrounding the 172 civilian fatalities which occurred in the 2009 Victorian 'Black Saturday' bushfires, through the examination of a detailed fatality dataset compiled by the Victorian Bushfires Royal Commission. This dataset allows detailed examination of Victorian bushfire safety policy ('Stay or go') in action on a day of extreme fire danger: from preparedness (both before and on the day of the fire) to behaviour on the day of the fire itself.This analysis presents three overarching findings. First, some aspects of 'Stay or go' appear to be supported: being well-prepared to evacuate remains the safest option in a bushfire; sheltering passively is very dangerous. Second, successful implementation of 'Stay or go' depends on a multitude of factors, which can challenge even the most capable householders. Third, events like Black Saturday challenge the 'Stay or go' approach, and indicate the need for a different approach on extreme fire danger days. We conclude by reflecting on the findings from this research in terms of the most recent changes to bushfire policy in Victoria.The project was funded by the Victorian Bushfires Royal Commission through the Bushfire Cooperative Research Centre. The Commission was involved in the project in an oversight capacity, in particular to ensure that strict confidence was maintained, and that conflicts of interest were avoided. Writing of this paper was supported through Saffron O’Neill’s ESRC Fellowship (S/K001175/1)
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