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Siri Jodha Singh Khalsa 《Boundary-Layer Meteorology》1980,19(1):3-17
The indirect dissipation technique is used to estimate 1-min averages of friction velocity u
*in the surface layer over the tropical ocean. These estimates are compared to estimates of u
*obtained using a drag coefficient and the relative difference between the two is examined in relation to stability and averaging time. Plumes and downdrafts are found to be responsible for an anomalous behavior of the drag coefficient estimates. Certain factors relating to plume properties, derived using conditional sampling as described in Khalsa (1980), are shown to be related to the variance between the two estimates of friction velocity. An investigation into the effects of increasing the averaging time reveals that plume spacing, which is dependent on stability, and the mean wind speed determine the minimum time for smoothing the influence of plumes and downdrafts.Department of Atmospheric Sciences contribution number 513. 相似文献
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Natural Hazards - This paper utilizes a multi-level governance framework to explain how and at what scale climate adaptation, exemplified by flood risk management, was governed in the medium-scale... 相似文献
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This paper analyses factors that contributed to the evolution of SO2, NOx and CO2 emissions in Europe from 1960 to 2010. Historical energy balances, along with population and economic growth data, are used to quantify the impacts of major determinants of changing emission levels, including energy intensity, conversion efficiency, fuel mix, and pollution control. Time series of emission levels are compared for countries in Western and Eastern Europe, throwing light on differences in the importance of particular emission-driving forces. Three quarters of the decline in SO2 emissions in Western Europe resulted from a combination of reduced energy intensity and improved fuel mix, while dedicated end-of-pipe abatement measures played a dominant role in the reduction of NOx emissions. The increase in atmospheric emissions in Eastern Europe through the mid-1990s was associated with the growth of energy-intensive industries, which off-setted the positive impact of better fuel quality and changes in fuel mix. A continuous decrease in energy intensity and higher conversion efficiencies have been the main factors responsible for the moderate rate of growth of European CO2 emissions. 相似文献
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Siri Jodha Singh Khalsa 《Boundary-Layer Meteorology》1980,19(2):135-153
A conditional sampling technique is used to provide statistics of surface-layer plume properties. A selection criterion based on the high-frequency variance of the horizontal wind component enables an accurate division of plume and nonplume states. The intermittency factor derived with this technique closely matches values obtained using other techniques at various heights in the atmospheric boundary layer. The intermittency factor in addition to other plume statistics are found to be stability dependent. Conditional averages are used to produce scatter diagrams from which the interrelationships between properties of both the plume and nonplume states can be examined. Several provocative relationships discovered in this way are discussed.An extensive investigation into the bimodal nature of the fine structure of turbulence is described. These results provide the most compelling support for the division of surface-layer turbulence into separate states. Length scales derived from the second moments of distributions fitted to conditionally sampled data are found to correlate with external parameters of the flow.Department of Atmospheric Sciences contribution number 514. 相似文献
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Richard J. T. Klein Siri E. H. Eriksen Lars Otto Næss Anne Hammill Thomas M. Tanner Carmenza Robledo Karen L. O’Brien 《Climatic change》2007,84(1):23-44
The need to mainstream adaptation to climate change into development planning and ongoing sectoral decision-making is increasingly
recognised, and several bilateral and multilateral development agencies are starting to take an interest. Over the past years
at least six development agencies have screened their project portfolios, generally with two goals in mind: (1) to ascertain
the extent to which existing development projects already consider climate risks or address vulnerability to climate variability
and change, and (2) to identify opportunities for incorporating climate change explicitly into future projects. As each portfolio
screening was conducted independently, the broader lessons emerging from the screenings have not been systematically analysed.
In this paper we assess the screening activities to date, focusing on both the results and the methods applied. Based on this
assessment we identify opportunities for development agencies to expand their current focus on the links between climate and
development. Most agencies already consider climate change as a real but uncertain threat to future development, but they
have given less thought to how different development patterns might affect vulnerability to climate change. The screenings
undertaken have shown the need to take a comprehensive approach to adaptation and its integration into development planning
and sectoral decision-making, and a number of policy initiatives have been taken to promote such integration. We provide some
initial guidance as to how portfolio screening can be carried out in a way that would allow agencies to assess systematically
the relevance of climate change to their ongoing and planned development projects. 相似文献
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Siri Veland Richard Howitt Dale Dominey-Howes Frank Thomalla Donna Houston 《Global Environmental Change》2013,23(1):314-326
The challenge of reaching common understanding of the processes and significance of environmental change amounts to a procedural vulnerability in climate change research that hinders successfully translating knowledge into equitable and effective adaptation policy. This article presents findings from research with Indigenous participants in West Arnhem, Australia, and identifies a procedural vulnerability to climate change research, where perceptions of change and their meaning have their context in Dreaming that supersedes and parallels Western scientific discourses of hazard and risk, but that are marginalised in studies and policies on climate change. This paper argues that moves to adapt remote Indigenous Australian communities to climate change risk missing the mark if they (a) assume that a strong reliance on particular ecosystem configurations makes Indigenous cultures universally vulnerable to environmental change, (b) do not recognise cosmologically embedded risks that are determined by Indigenous capacity to take care of country, and (c) do not recognise colonisation as an ongoing disaster in Indigenous Nations, and therefore treat secondary disasters such as poverty, ill health and welfare dependence as primary contributors to high climate change vulnerability. Procedural vulnerabilities contribute to policy failure, and in Australian contexts pose a risk of conceiving solutions to climate change vulnerability that involve moving people out of the way of environmental risks as they are conceived within colonial traditions, while moving them into the way of risks as conceived through the eyes of remote Indigenous communities. This research joins recent publications that encourage researchers and policy-makers to epistemologically ground proof risk assessments and to listen and engage in conversations that create ways of ‘seeing with both eyes’, while not being blind to the hazards of colonisation. 相似文献
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