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21.
Anthony G. Patt Detlef P. van Vuuren Frans Berkhout Asbjørn Aaheim Andries F. Hof Morna Isaac Reinhard Mechler 《Climatic change》2010,99(3-4):383-402
Adaptation is an important element on the climate change policy agenda. Integrated assessment models, which are key tools to assess climate change policies, have begun to address adaptation, either by including it implicitly in damage cost estimates, or by making it an explicit control variable. We analyze how modelers have chosen to describe adaptation within an integrated framework, and suggest many ways they could improve the treatment of adaptation by considering more of its bottom-up characteristics. Until this happens, we suggest, models may be too optimistic about the net benefits adaptation can provide, and therefore may underestimate the amount of mitigation they judge to be socially optimal. Under some conditions, better modeling of adaptation costs and benefits could have important implications for defining mitigation targets. 相似文献
22.
A global perspective on African climate 总被引:4,自引:1,他引:3
Alessandra Giannini Michela Biasutti Isaac M. Held Adam H. Sobel 《Climatic change》2008,90(4):359-383
We describe the global climate system context in which to interpret African environmental change to support planning and implementation of policymaking action at national, regional and continental scales, and to inform the debate between proponents of mitigation v. adaptation strategies in the face of climate change. We review recent advances and current challenges in African climate research and exploit our physical understanding of variability and trends to shape our outlook on future climate change. We classify the various mechanisms that have been proposed as relevant for understanding variations in African rainfall, emphasizing a “tropospheric stabilization” mechanism that is of importance on interannual time scales as well as for the future response to warming oceans. Two patterns stand out in our analysis of twentieth century rainfall variability: a drying of the monsoon regions, related to warming of the tropical oceans, and variability related to the El Niño–Southern Oscillation. The latest generation of climate models partly captures this recent continent-wide drying trend, attributing it to the combination of anthropogenic emissions of aerosols and greenhouse gases, the relative contribution of which is difficult to quantify with the existing model archive. The same climate models fail to reach a robust agreement regarding the twenty-first century outlook for African rainfall, in a future with increasing greenhouse gases and decreasing aerosol loadings. Such uncertainty underscores current limitations in our understanding of the global climate system that it is necessary to overcome if science is to support Africa in meeting its development goals. 相似文献
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This paper presents real-time monitoring data and analysis results of the non-stationary vibrations of an operational wind turbine. The advanced time-frequency spectrum analysis reveals varied non-stationary vibrations with timevarying frequencies, which are correlated with certain system natural modes characterized by finite element analysis. Under the effects of strong wind load, the wind turbine system exhibits certain resonances due to blade passing excitations. The system also exhibits certain instabilities due to the coupling of the tower bending modes and blade flapwise mode with blade passing excitations under the variation of wind speed. An analytical model is used to elaborate the non-stationary and instability phenomena observed in experimental results. The properties of the nonlinear instabilities are evaluated by using Lyapunov exponent estimation. 相似文献
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26.
I. Gultepe G. A. Isaac P. Joe P. A. Kucera J. M. Theriault T. Fisico 《Pure and Applied Geophysics》2014,171(1-2):59-85
The objective of this work is to better understand and summarize the mountain meteorological observations collected during the Science of Nowcasting Winter Weather for the Vancouver 2010 Olympics and Paralympics (SNOW-V10) project that was supported by the Fog Remote Sensing and Modeling (FRAM) project. The Roundhouse (RND) meteorological station was located 1,856 m above sea level that is subject to the winter extreme weather conditions. Below this site, there were three additional observation sites at 1,640, 1,320, and 774 m. These four stations provided some or all the following measurements at 1 min resolution: precipitation rate (PR) and amount, cloud/fog microphysics, 3D wind speed (horizontal wind speed, U h; vertical air velocity, w a), visibility (Vis), infrared (IR) and shortwave (SW) radiative fluxes, temperature (T) and relative humidity with respect to water (RHw), and aerosol observations. In this work, comparisons are made to assess the uncertainties and variability for the measurements of Vis, RHw, T, PR, and wind for various winter weather conditions. The ground-based cloud imaging probe (GCIP) measurements of snow particles using a profiling microwave radiometer (PMWR) data have also been shown to assess the icing conditions. Overall, the conclusions suggest that uncertainties in the measurements of Vis, PR, T, and RH can be as large as 50, >60, 50, and >20 %, respectively, and these numbers may increase depending on U h, T, Vis, and PR magnitude. Variability of observations along the Whistler Mountain slope (~500 m) suggested that to verify the models, model space resolution should be better than 100 m and time scales better than 1 min. It is also concluded that differences between observed and model based parameters are strongly related to a model’s capability of accurate prediction of liquid water content (LWC), PR, and RHw over complex topography. 相似文献
27.
Isaac V. Fine Evgueni A. Kulikov Josef Y. Cherniawsky 《Pure and Applied Geophysics》2013,170(6-8):1295-1307
We use a numerical tsunami model to describe wave energy decay and transformation in the Pacific Ocean during the 2011 Tohoku tsunami. The numerical model was initialised with the results from a seismological finite fault model and validated using deep-ocean bottom pressure records from DARTs, from the NEPTUNE-Canada cabled observatory, as well as data from four satellite altimetry passes. We used statistical analysis of the available observations collected during the Japan 2011 tsunami and of the corresponding numerical model to demonstrate that the temporal evolution of tsunami wave energy in the Pacific Ocean leads to the wave energy equipartition law. Similar equipartition laws are well known for wave multi-scattering processes in seismology, electromagnetism and acoustics. We also show that the long-term near-equilibrium state is governed by this law: after the passage of the tsunami front, the tsunami wave energy density tends to be inversely proportional to the water depth. This fact leads to a definition of tsunami wave intensity that is simply energy density times the depth. This wave intensity fills the Pacific Ocean basin uniformly, except for the areas of energy sinks in the Southern Ocean and Bering Sea. 相似文献
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29.
This paper is part of a larger community health study aimed at delineating the determinants of health in Sarnia. The paper
specifically investigates Sarnia residents’ daily lived experiences, perceptions of and responses to living within the St.
Clair River “Area of Concern” (AOC) as designated by the federal government based on the hypothesis that relatively high levels
of environmental pollution in the region are negatively influencing human health. Results from in-depth interviews (N = 27) show that residents of Sarnia are conflicted by the elevation of awareness about environmental health threats by being
labelled within an AOC. Residents use their emotional and sensual experiences to adopt appropriate coping strategies to live
within a contaminated community. In contextualizing their everyday lived realities, residents argued that living in an AOC
demands personal acceptance of the conditions in Sarnia and awareness of “bad air days” to cope with pollution exposure. Yet,
residents were not willing to abandon Sarnia because of their cultural, social, and economical attachments to the place they
call home. These findings suggest the need for local health policies that incorporate local concerns and perceptions of how
environmental pollution affects people’s experiences and well-being. There is a necessity to involve community members as
central participants in the process of policy making. 相似文献
30.
Isaac R. Santos Jason de Weys Douglas R. Tait Bradley D. Eyre 《Estuaries and Coasts》2013,36(1):56-73
Four months of daily nutrient and radon (a natural groundwater tracer) observations at the outlet of a heavily drained coastal wetland illustrated how episodic floods and diffuse groundwater seepage influence the biogeochemistry of a sub-tropical estuary (Richmond River, New South Wales, Australia). Our observations downstream of the Tuckean Swamp (an acid sulphate soil floodplain) covered a dry stage, a flood triggered by a 213-mm rain event and a post-flood stage when surface water chemistry was dominated by groundwater discharge. Significant correlations were found between radon and ammonium and N/P ratios and between radon and dissolved organic nitrogen (DON) during the post-flood stage. While the flood lasted for 14?% of the time of the surface water time series, it accounted for 18?% of NH4, 32?% of NO x , 66?% of DON, 58?% of PO4 and 55?% of dissolved organic phosphorus (DOP) catchment exports. Over the 4-month study period, groundwater fluxes of 35.0, 3.6, 36.3, 0.5 and 0.7?mmol?m?2?day?1 for NH4, NO x , DON, PO4 and DOP, respectively, were estimated. The groundwater contribution to the total surface water catchment exports was nearly 100?% for ammonium, and <20?% for the other nutrients. Post-flood groundwater seepage shifted the system from a DON to a dissolved inorganic N-dominated system and doubled N/P ratios in surface waters. We hypothesise that the Richmond River Estuary N/P ratios may reflect a widespread trend of tidal rivers and estuaries becoming more groundwater-dominated and phosphorus-limited as coastal wetlands are drained for agriculture, grazing and development. 相似文献