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51.
Sensitivity Analysis of Emissions Corridors for the 21st Century 总被引:1,自引:1,他引:0
We investigate the sensitivity of emissions corridors for the 21st century to various factors that are currently under debate in the climate change arena. Emissions corridors represent the range of admissible emissions futures that observe some predefined guardrails on the future development of the human-climate system. They are calculated on the conceptual and methodological basis of the tolerable windows approach. We assess the sensitivity of the corridors to the choice of time-resolved as well as intertemporally aggregated guardrails that exclude an intolerable amount of climate change on the one hand and unbearable mitigation burdens on the other. In addition, we investigate the influence of climate sensitivity on the corridors.Results show a large dependence of emissions corridors on the choice of guardrails and the value of climate sensitivity T
2CO
2. If the guardrail on climate change is specified in terms of a maximum admissible global mean temperature increase T
max to be observed at any time, the size of the corridors is predominantly determined by a climate impact resilience parameter =T
max/T
2CO
2. As is varied from values below 0.5 to values above 1.5, we move from cases where no emissions profile whatsoever can observe all guardrails, to cases where no significant emissions reduction seems necessary given the range of emissions scenarios for the 21st century. The limits on admissible mitigation efforts influence predominantly the timing and the economic viability of emissions reductions. A large mitigation flexibility allows for wait then run emissions paths, while low flexibility asks for a significantly more prudent approach. 相似文献
52.
Eugene S. Ilton Chongxuan Liu Wassana Yantasee Zheming Wang Dean A. Moore Andrew R. Felmy John M. Zachara 《Geochimica et cosmochimica acta》2006,70(19):4836-4849
Uranyl silicates such as uranophane and Na-boltwoodite appear to control the solubility of uranium in certain contaminated sediments at the US Department of Energy Hanford site [Liu, C., Zachara, J.M., Qafoku, O., McKinley, J.P., Heald, S.M., Wang, Z. 2004. Dissolution of uranyl microprecipitates in subsurface sediments at Hanford Site, USA. Geochim. Cosmochim. Acta68, 4519-4537.]. Consequently, the solubility of synthetic Na-boltwoodite, Na(UO2)(SiO3OH) · 1.5H2O, was determined over a wide range of bicarbonate concentrations, from circumneutral to alkaline pH, that are representative of porewater and groundwater compositions at the Hanford site and calcareous environments generally. Experiments were open to air. Results show that Na-boltwoodite dissolution was nearly congruent and its solubility and dissolution kinetics increased with increasing bicarbonate concentration and pH. A consistent set of solubility constants were determined from circumneutral pH (0 added bicarbonate) to alkaline pH (50 mM added bicarbonate). Average or 5.85 ± 0.0.26; using the Pitzer ion-interaction model or Davies equation, respectively. These values are close to the one determined by [Nguyen, S.N., Silva, R.J., Weed, H.C., Andrews, Jr., J.E., 1992. Standard Gibbs free energies of formation at the temperature 303.15 K of four uranyl silicates: soddyite, uranophane, sodium boltwoodite, and sodium weeksite. J. Chem. Thermodynamics24, 359-376.] under very different conditions (pH 4.5, Ar atmosphere). 相似文献
53.
Jason A. Leach James M. Buttle Kara L. Webster Paul W. Hazlett Dean S. Jeffries 《水文研究》2020,34(10):2154-2175
The time it takes water to travel through a catchment, from when it enters as rain and snow to when it leaves as streamflow, may influence stream water quality and catchment sensitivity to environmental change. Most studies that estimate travel times do so for only a few, often rain-dominated, catchments in a region and use relatively short data records (<10 years). A better understanding of how catchment travel times vary across a landscape may help diagnose inter-catchment differences in water quality and response to environmental change. We used comprehensive and long-term observations from the Turkey Lakes Watershed Study in central Ontario to estimate water travel times for 12 snowmelt-dominated headwater catchments, three of which were impacted by forest harvesting. Chloride, a commonly used water tracer, was measured in streams, rain, snowfall and as dry atmospheric deposition over a 31 year period. These data were used with a lumped convolution integral approach to estimate mean water travel times. We explored relationships between travel times and catchment characteristics such as catchment area, slope angle, flowpath length, runoff ratio and wetland coverage, as well as the impact of harvesting. Travel time estimates were then used to compare differences in stream water quality between catchments. Our results show that mean travel times can be variable for small geographic areas and are related to catchment characteristics, in particular flowpath length and wetland cover. In addition, forest harvesting appeared to decrease mean travel times. Estimated mean travel times had complex relationships with water quality patterns. Results suggest that biogeochemical processes, particularly those present in wetlands, may have a greater influence on water quality than catchment travel times. 相似文献
54.
Amit K. Pradhananga Mae A. Davenport David C. Fulton Geoffrey M. Maruyama Dean Current 《社会与自然资源》2017,30(2):212-227
This study applies an integrated moral obligation model to examine the role of environmental and cultural values, and beliefs in the activation of landowner conservation norms. Data for this study were collected through a self-administered survey of riparian landowners in two Minnesota watersheds: Sand Creek and Vermillion River watersheds. Study findings suggest that collectivistic and biospheric–altruistic values form the bases for the activation of personal norms. Further, beliefs about local responsibility and ability to act influence personal norms to protect water resources. Findings suggest that landowners’ personal norms of water conservation are more likely to be activated by conservation strategies that appeal to biospheric–altruistic and collectivistic values, emphasize adverse consequences of water pollution, highlight water resource protection as a local responsibility, and provide the resources needed to protect water resources. 相似文献
55.
Coupling land use allocation models with raster GIS 总被引:5,自引:0,他引:5
As geographic information systems (GIS) have moved from information storage and retrieval operations towards more decision
support functions, there is a need for more integration of spatial analytical modules that can assist in locational decisions.
This paper presents a methodology for coupling land use allocation models with a raster GIS. For raster systems, the integration
of any decision module has been limited by the size of raster datasets that may contain hundreds of thousands of pixels. Therefore,
decision heuristics have been used rather than exact methods such as mathematical programming models. For the problem of land
use allocation, the special structure of the generalized assignment problem is used here to handle large scale datasets. The
advantage of the mathematical programming approach is the additional information associated with the dual variables and opportunity
costs that can be used in subsequent sensitivity analyses.
Received: 7 April 1998/Accepted: 2 October 1998 相似文献
56.
The output from the hydraulic vibrators typically used for land seismic surveys is controlled by monitoring the acceleration measured by accelerometers mounted on the reaction mass and baseplate. The considerable energy output by such vibrators, which are coupled with the sensitivity of the accelerometers used, results in crosstalk if more than one vibrator is being used. In this paper, we present the results of a field experiment in which we measured the crosstalk between two adjacent vibrators. We found that the level of crosstalk was approximately ‐20 dB when the vibrators were adjacent but decreased with increasing frequency and separation. This result has implications for measurements of vibrator performance, source‐signature deconvolution, and in particular, estimates of the total energy output by a fleet of vibrators. 相似文献
57.
Peter W. Webley Kenneson Dean John E. Bailey Jon Dehn Rorik Peterson 《Natural Hazards》2009,51(2):345-361
There are over 100 active volcanoes in the North Pacific (NOPAC) region, most of which are located in sparsely populated areas. Dispersion models play an important role in forecasting the movement of volcanic ash clouds by complementing both remote sensing data and visual observations from the ground and aircraft. Puff is a three-dimensional dispersion model, primarily designed for forecasting volcanic ash dispersion, used by the Alaska Volcano Observatory and other agencies. Since early 2007, the model is in an automated mode to predict the movement of airborne volcanic ash at multiple elevated alert status volcanoes worldwide to provide immediate information when an eruption occurs. Twelve of the predictions are within the NOPAC region, nine more within the southern section of the Pacific ring of fire and the others are in Europe and the Caribbean. Model forecasts are made for initial ash plumes ranging from 4 to 20 km altitude above sea level and for a 24-h forecast period. This information is made available via the Puff model website. Model results can be displayed in Virtual Globes for three-dimensional visualization. Here, we show operational Puff predictions in two and three-dimensions in Google Earth®, both as iso-surfaces and particles, and study past eruptions to illustrate the capabilities that the Virtual Globes can provide. In addition, we show the opportunity that Google Maps® provides in displaying Puff operational predictions via an application programming web interface and how radiosonde data (vertical soundings) and numerical weather prediction vertical profiles can be displayed in Virtual Globes for assisting in estimating ash cloud heights. 相似文献
58.
Applying segment-wise altimetry-based gravest empirical mode method to expendable bathythermograph temperature, Argo salinity, and altimetric sea surface height data in March, June, and November from San Francisco to near Japan (30° N, 145° E) via Honolulu, we estimated the component of the heat transport variation caused by change in the southward interior geostrophic flow of the North Pacific subtropical gyre in the top 700 m layer during 1993–2012. The volume transport-weighted temperature (TI) is strongly dependent on the season. The anomaly of TI from the mean seasonal variation, whose standard deviation is 0.14°C, was revealed to be caused mainly by change in the volume transport in a potential density layer of 25.0?25.5σ??. The anomaly of TI was observed to vary on a decadal or shorter, i.e., quasi-decadal (QD), timescale. The QD-scale variation of TI had peaks in 1998 and 2007, equivalent to the reduction in the net heat transport by 6 and 10 TW, respectively, approximately 1 year before those of sea surface temperature (SST) in the warm pool region, east of the Philippines. This suggests that variation in TI affects the warm pool SST through modification of the heat balance owing to the entrainment of southward transported water into the mixed layer. 相似文献
59.
To assess whether reaches of the Motueka River (New Zealand) that gain water from groundwater were likely to represent significant cold-water refugia for brown trout during periods of high water temperatures, water temperature was monitored for more than 18 months in two gaining reaches of the Motueka River and three reaches that were predicted to be losing water to groundwater. These data were used to predict brown trout (Salmo trutta) growth in gaining and losing reaches. Groundwater inputs had a small effect on water temperature at the reach-scale and modelling suggests that the differences observed were unlikely to result in appreciable differences in trout growth. Several coldwater patches were identified within the study reach that were up to 3.5°C cooler than the mainstem, but these were generally shallow and were unlikely to provide refuge for adult trout. The exception was Hinetai Spring, which had a mean water temperature of close to 16°C during the period January–March, when temperatures in the mainstem regularly exceeded 19°C. Trout were observed within the cold-water plume at the mouth of Hinetai Stream, which would allow them to thermoregulate when mainstem temperatures are unfavourable while still being able to capitalise on food resources available in the mainstem. 相似文献
60.
Denis J. Dean 《Transactions in GIS》2013,17(2):159-181
Geospatial data analysis techniques are widely used to find optimal routes from specified starting points to specified destinations. Optimality is defined in terms of minimizing some impedance value over the length of the route – the value to be minimized might be distance, travel time, financial cost, or any other metric. Conventional analysis procedures assume that impedance values of all possible travel routes are known a priori, and when this assumption holds, efficient solution strategies exist that allow truly optimal solutions to be found for even very large problems. When impedance values are not known with certainty a priori, exact solution strategies do not exist and heuristics must be employed. This study evaluated how the quality of the solutions generated by one such heuristic were impacted by the nature of the uncertainty in the cost database, the nature of the costs themselves, and the parameters used in the heuristic algorithm. It was found that all of these factors influenced the qualities of the solutions produced by the heuristic, but encouragingly, an easily controlled parameter of the heuristic algorithm itself played the most important role in controlling solution quality. 相似文献