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排序方式: 共有419条查询结果,搜索用时 15 毫秒
81.
Elizabeth Holcombe Sarah Smith Edmund Wright Malcolm G. Anderson 《Natural Hazards》2012,61(2):351-385
Despite the recognition of the need for mitigation approaches to landslide risk in developing countries, the delivery of ‘on-the-ground’
measures is rarely undertaken. With respect to other ‘natural’ hazards, it is widely reported that mitigation can pay. However,
the lack of such an evidence base in relation to landslides in developing countries hinders advocacy amongst decision makers
for expenditure on ex-ante measures. This research addresses these limitations directly by developing and applying an integrated
risk assessment and cost–benefit analysis of physical landslide mitigation measures implemented in an unplanned community
in the Eastern Caribbean. In order to quantify the level of landslide risk reduction achieved, landslide hazard and vulnerability
were modelled (before and after the intervention), and project costs, direct and indirect benefits were monetised. It is shown
that the probability of landslide occurrence has been substantially reduced by implementing surface-water drainage measures
and that the benefits of the project outweigh the costs by a ratio of 2.7–1. This paper adds to the evidence base that ‘mitigation
pays’ with respect to landslide risk in the most vulnerable communities—thus strengthening the argument for ex-ante measures.
This integrated project evaluation methodology should be suitable for adoption as part of the community-based landslide mitigation
project cycle, and it is hoped that this resource, and the results of this study, will stimulate further such programmes. 相似文献
82.
Duncan A. Christie Jos�� A. Boninsegna Malcolm K. Cleaveland Antonio Lara Carlos Le Quesne Mariano S. Morales Manfred Mudelsee David W. Stahle Ricardo Villalba 《Climate Dynamics》2011,36(7-8):1505-1521
The Andes Cordillera acts as regional ??Water Towers?? for several countries and encompasses a wide range of ecosystems and climates. Several hydroclimatic changes have been described for portions of the Andes during recent years, including glacier retreat, negative precipitation trends, an elevation rise in the 0° isotherm, and changes in regional streamflow regimes. The Temperate-Mediterranean transition (TMT) zone of the Andes (35.5°?C39.5°S) is particularly at risk to climate change because it is a biodiversity hotspot with heavy human population pressure on water resources. In this paper we utilize a new tree-ring network of Austrocedrus chilensis to reconstruct past variations in regional moisture in the TMT of the Andes by means of the Palmer Drought Severity Index (PDSI). The reconstruction covers the past 657?years and captures interannual to decadal scales of variability in late spring?Cearly summer PDSI. These changes are related to the north?Csouth oscillations in moisture conditions between the Mediterranean and Temperate climates of the Andes as a consequence of the latitudinal position of the storm tracks forced by large-scale circulation modes. Kernel estimation of occurrence rates reveals an unprecedented increment of severe and extreme drought events during the last century in the context of the previous six centuries. Moisture conditions in our study region are linked to tropical and high-latitude ocean-atmospheric forcing, with PDSI positively related to Ni?o-3.4 SST during spring and strongly negatively correlated with the Antarctic Oscillation (AAO) during summer. Geopotential anomaly maps at 500-hPa show that extreme dry years are tightly associated with negative height anomalies in the Ross?CAmundsen Seas, in concordance with the strong negative relationship between PDSI and AAO. The twentieth century increase in extreme drought events in the TMT may not be related to ENSO but to the positive AAO trend during late-spring and summer resulting from a gradual poleward shift of the mid-latitude storm tracks. This first PDSI reconstruction for South America demonstrates the highly significant hindcast skill of A. chilensis as an aridity proxy. 相似文献
83.
Developing coastal adaptation to climate change in the New York City infrastructure-shed: process, approach, tools, and strategies 总被引:1,自引:0,他引:1
Cynthia Rosenzweig William D. Solecki Reginald Blake Malcolm Bowman Craig Faris Vivien Gornitz Radley Horton Klaus Jacob Alice LeBlanc Robin Leichenko Megan Linkin David Major Megan O��Grady Lesley Patrick Edna Sussman Gary Yohe Rae Zimmerman 《Climatic change》2011,106(1):93-127
While current rates of sea level rise and associated coastal flooding in the New York City region appear to be manageable by stakeholders responsible for communications, energy, transportation, and water infrastructure, projections for sea level rise and associated flooding in the future, especially those associated with rapid icemelt of the Greenland and West Antarctic Icesheets, may be outside the range of current capacity because extreme events might cause flooding beyond today??s planning and preparedness regimes. This paper describes the comprehensive process, approach, and tools for adaptation developed by the New York City Panel on Climate Change (NPCC) in conjunction with the region??s stakeholders who manage its critical infrastructure, much of which lies near the coast. It presents the adaptation framework and the sea-level rise and storm projections related to coastal risks developed through the stakeholder process. Climate change adaptation planning in New York City is characterized by a multi-jurisdictional stakeholder?Cscientist process, state-of-the-art scientific projections and mapping, and development of adaptation strategies based on a risk-management approach. 相似文献
84.
85.
Esler D Ballachey BE Trust KA Iverson SA Reed JA Miles AK Henderson JD Woodin BR Stegeman JJ McAdie M Mulcahy DM Wilson BW 《Marine pollution bulletin》2011,62(3):609-614
We examined hepatic EROD activity, as an indicator of CYP1A induction, in Barrow’s goldeneyes captured in areas oiled during the 1989 Exxon Valdez spill and those from nearby unoiled areas. We found that average EROD activity differed between areas during 2005, although the magnitude of the difference was reduced relative to a previous study from 1996/1997, and we found that areas did not differ by 2009. Similarly, we found that the proportion of individuals captured from oiled areas with elevated EROD activity (?2 times unoiled average) declined from 41% in winter 1996/1997 to 10% in 2005 and 15% in 2009. This work adds to a body of literature describing the timelines over which vertebrates were exposed to residual Exxon Valdez oil and indicates that, for Barrow’s goldeneyes in Prince William Sound, exposure persisted for many years with evidence of substantially reduced exposure by 2 decades after the spill. 相似文献
86.
87.
Harris E. Mason Paolo Montagna Laura Kubista Malcolm McCulloch 《Geochimica et cosmochimica acta》2011,75(23):7446-7457
Recent development of paleo-nutrient proxies based on the phosphorus/calcium (P/Ca) ratio in tropical- and deep-water corals (also known as cold-water corals) require an understanding of the processes by which P is incorporated into the coral skeletal aragonite. Here, we apply single- and double-resonance solid-state nuclear magnetic resonance (NMR) spectroscopy to determine the speciation of P in coral aragonite. The results show that the majority of P occurs as phosphate defects in the aragonite structure, but in many samples a significant fraction of the P occurs also in crystalline hydroxylapatite inclusions. Quantification of the amount of hydroxylapatite indicates that its presence is not related simply to external environmental factors and that it can occur at varying abundances in different parts of the same corallite. Since there is currently no model available to describe the relationship between dissolved inorganic phosphate and its incorporation as apatite inclusions into carbonates, careful screening of samples which contain only phosphate in the aragonite structure or selective microsampling could improve proxy development. 相似文献
88.
Iain M. Suthers Jock W. YoungMark E. Baird Moninya RoughanJason D. Everett Gary B. BrassingtonMaria Byrne Scott A. CondieJason R. Hartog Christel S. HasslerAlistair J. Hobday Neil J. HolbrookHamish A. Malcolm Peter R. OkePeter A. Thompson Ken Ridgway 《Deep Sea Research Part II: Topical Studies in Oceanography》2011,58(5):538-546
The poleward flowing East Australian Current (EAC) is characterised by its separation from the coast, 100-200 nautical miles north of Sydney, to form the eastward flowing Tasman Front and a southward flowing eddy field. The separation zone greatly influences coastal ecosystems for the relatively narrow continental shelf (only 15-50 km wide), particularly between 32-34°S. In this region the continental shelf has a marked shift in the seasonal temperature-salinity relationship and elevated surface nitrate concentrations. This current parallels the portion of the coast where Australia’s population is concentrated and has a long history of scientific research. However, understanding of physical and biological processes driven by the EAC, particularly in linking circulation to ecosystems, is limited. In this special issue of 16 papers on the EAC, we examine the effects of climatic wind-stress forced ocean dynamics on EAC transport variability and coastal sea level, from ENSO to multi-decadal time scales; eddy formation and structure; fine scale connectivity and larval retention. Comparisons with the poleward-flowing Leeuwin Current on Australia’s west coast show differences in ecosystem productivity that can be attributed to the underlying physics in each region. On average there is double the chlorophyll a concentration on the east coast than the west. In comparison to the Leeuwin, the EAC may have less local retention of larvae and act as a partial barrier to onshore transport, which may also be related to the local spawning and early life history of small pelagic fish on each coast. Inter-annual variations in the EAC transport produce a detectable sea-level signal in Sydney Harbour, which could provide a useful fisheries index as does the Fremantle sea level and Leeuwin Current relationship. The EAC’s eddy structure and formation by the EAC are examined. A particular cold-core eddy is shown to have a “tilt” towards the coast, and that during a rotation the flow of particles may rise up to the euphotic zone and then down beneath. In a warm-core eddy, surface flooding is shown to produce a new shallower surface mixed layer and promote algal growth. An assessment of plankton data from 1938-1942 showed that the local, synoptic conditions had to be incorporated before any comparison with the present. There are useful relationships of water mass characteristics in the Tasman Sea and separation zone with larval fish diversity and abundance, as well as with long-line fisheries. These fisheries-pelagic habitat relationships are invaluable for fisheries management, as well as for climate change assessments.There is further need to examine the EAC influence on rainfall, storm activity, dust deposition, and on the movements by fish, sharks and whales. The Australian Integrated Marine Observing System (IMOS) has provided new infrastructure to determine the changing behaviour of the EAC and its bio-physical interaction with the coasts and estuaries. The forecasting and hindcasting capability developed under the Bluelink project has provided a new tool for data synthesis and dynamical analysis. The impact of a strengthening EAC and how it influences the livelihoods of over half the Australian population, from Brisbane to Sydney, Hobart and Melbourne, is just being realised. 相似文献
89.
90.
Hagger JA Jones MB Lowe D Leonard DR Owen R Galloway TS 《Marine pollution bulletin》2008,56(6):1111-1118
To answer the requirement of the European Commission's Water Framework Directive (WFD) for biological-effects endpoints to classify the ecological health of aquatic ecosystems, we propose the biomarker response index (BRI). The BRI, based on a suite of biomarkers at different levels of biological response at the individual level, provides an integrated relative measure of the general health status of coastal invertebrates. Using the BRI, the health of mussels (Mytilus edulis) from 10 estuaries classified by the Environment Agency of England and Wales under the WFD was compared. Eight sites were healthier than predicted and two showed a similar health status to that of the predicted point-source pollution risk classification. Results indicate that the BRI offers a potential measure of organism health that can be used in monitoring under the WFD as an additional aid to reduce uncertainty in defining risk classification and to provide better evidence of existing impact. 相似文献