Robustness of pattern scaled climate change scenarios for adaptation decision support     

Ana Lopez  Emma B. Suckling  Leonard A. Smith 《Climatic change》2014,122(4):555-566

Pattern scaling offers the promise of exploring spatial details of the climate system response to anthropogenic climate forcings without their full simulation by state-of-the-art Global Climate Models. The circumstances in which pattern scaling methods are capable of delivering on this promise are explored by quantifying its performance in an idealized setting. Given a large ensemble that is assumed to sample the full range of variability and provide quantitative decision-relevant information, the soundness of applying the pattern scaling methodology to generate decision relevant climate scenarios is explored. Pattern scaling is not expected to reproduce its target exactly, of course, and its generic limitations have been well documented since it was first proposed. In this work, using as a particular example the quantification of the risk of heat waves in Southern Europe, it is shown that the magnitude of the error in the pattern scaled estimates can be significant enough to disqualify the use of this approach in quantitative decision-support. This suggests that future application of pattern scaling in climate science should provide decision makers not just a restatement of the assumptions made, but also evidence that the methodology is adequate for purpose in practice for the case under consideration.  相似文献   

Tsunami hazard assessment of Canada     

Lucinda J. Leonard  Garry C. Rogers  Stéphane Mazzotti 《Natural Hazards》2014,70(1):237-274

We present a preliminary probabilistic tsunami hazard assessment of Canadian coastlines from local and far-field, earthquake, and large submarine landslide sources. Analyses involve published historical, palaeotsunami and palaeoseismic data, modelling, and empirical relations between fault area, earthquake magnitude, and tsunami run-up. The cumulative estimated tsunami hazard for potentially damaging run-up (≥1.5 m) of the outer Pacific coastline is ~40–80 % in 50 years, respectively one and two orders of magnitude greater than the outer Atlantic (~1–15 %) and the Arctic (<1 %). For larger run-up with significant damage potential (≥3 m), Pacific hazard is ~10–30 % in 50 years, again much larger than both the Atlantic (~1–5 %) and Arctic (<1 %). For outer Pacific coastlines, the ≥1.5 m run-up hazard is dominated by far-field subduction zones, but the probability of run-up ≥3 m is highest for local megathrust sources, particularly the Cascadia subduction zone; thrust sources further north are also significant, as illustrated by the 2012 Haida Gwaii event. For Juan de Fuca and Georgia Straits, the Cascadia megathrust dominates the hazard at both levels. Tsunami hazard on the Atlantic coastline is dominated by poorly constrained far-field subduction sources; a lesser hazard is posed by near-field continental slope failures similar to the 1929 Grand Banks event. Tsunami hazard on the Arctic coastline is poorly constrained, but is likely dominated by continental slope failures; a hypothetical earthquake source beneath the Mackenzie delta requires further study. We highlight areas susceptible to locally damaging landslide-generated tsunamis, but do not quantify the hazard.  相似文献   

Spreading of submarine slopes caused by trenching     

Bing C. Yen  R. Leonard Allen 《Marine Georesources & Geotechnology》2013,31(1-4):101-116

Abstract

Submarine trenching for pipeline installation in potentially unstable sediments has recently been of increasing concern. Although typical pipeline depths are less than 3 or 4 m, trenching operations generally cause local stress concentrations within the sediments and induce excess pore pressures. The result of these stress concentrations and pore pressure increases may be spreading of submarine slumps that can endanger pipelines or other nearby installations. A simplified analytical approach is described to estimate the extent of slump spreading caused by trenching. It is shown that the spreading potential is affected by many geotechnical characteristics of the sediments in addition to geomorphic processes and the oceanographic regimes governing the area. The primary geotechnical factors that influence spreading include the porepressure parameter A_f , the degree of consolidation, the coefficient of earth pressure at rest, and the strength characteristics of the soil. Dimensionless parameters are developed to illustrate graphically the functional relationships among these parameters. A Gulf of Mexico soil profile is used to quantify the spreading phenomenon.  相似文献   

On the progenitors of core-collapse supernovae     

Douglas C. Leonard 《Astrophysics and Space Science》2011,336(1):117-122

Theory holds that a star born with an initial mass between about 8 and 140 times the mass of the Sun will end its life through the catastrophic gravitational collapse of its iron core to a neutron star or black hole. This core collapse process is thought to usually be accompanied by the ejection of the star’s envelope as a supernova. This established theory is now being tested observationally, with over three dozen core-collapse supernovae having had the properties of their progenitor stars directly measured through the examination of high-resolution images taken prior to the explosion. Here I review what has been learned from these studies and briefly examine the potential impact on stellar evolution theory, the existence of “failed supernovae”, and our understanding of the core-collapse explosion mechanism.  相似文献