Industrial sulfur demand: Analysis and prospect     

Edmonson  Nathan 《Natural Resources Research》1994,3(3):205-215

Weak growth in industrial (nonagricultural) U.S. sulfur demand has slowed the growth of total sulfur demand. Evaluating prospects for trend reversal is hampered by inadequate detailed data published by industry, and the lack of an easily measured demand component that reliably depicts total demand. In this article, I try to overcome this data deficiency by constructing an industry-by-industry breakdown of published data on total industrial sulfur consumption. Industrial sulfur consumptions were estimated from data on consuming industry activity, characteristics of relevant industrial processes, and analyses of the conditions affecting choice among alternative industrial processes. Subjective projections of the industry detail data are presented.In addition to cyclical factors, past declines in industrial sulfur demand were due to replacement of sulfur-using industrial processes with alternative processes that use less or no sulfur to achieve production cost economies. In some, but not all, cases, changeovers of process were in response to impositions of environmental-related requirements. The demand for industrial sulfur has good prospects for positive growth as shrinkage of some markets reaches natural limits and total market growth comes increasingly to be dominated by markets with positive growth prospects. Positive growth has been generated by environmentally related regulation in several markets, such as petroleum alkylation and copper production.  相似文献   

Potential Implications of PCM Climate Change Scenarios for Sacramento–San Joaquin River Basin Hydrology and Water Resources     

Nathan T. VanRheenen  Andrew W. Wood  Richard N. Palmer  Dennis P. Lettenmaier 《Climatic change》2004,62(1-3):257-281

The potential effects of climate change on the hydrology and water resources of the Sacramento–San Joaquin River Basin were evaluated using ensemble climate simulations generated by the U.S. Department of Energy and National Center for Atmospheric Research Parallel Climate Model (DOE/NCAR PCM). Five PCM scenarios were employed. The first three were ensemble runs from 1995–2099 with a `business as usual' global emissions scenario, eachwith different atmospheric initializations. The fourth was a `control climate'scenario with greenhouse gas emissions set at 1995 levels and run through 2099. The fifth was a historical climate simulation forced with evolving greenhouse gas concentrations from 1870–2000, from which a 50-yearportion is taken for use in bias-correction of the other runs. From these global simulations, transient monthly temperature and precipitation sequences were statistically downscaled to produce continuous daily hydrologic model forcings, which drove a macro-scale hydrology model of theSacramento–San Joaquin River Basins at a 1/8-degree spatial resolution, and produceddaily streamflow sequences for each climate scenario. Each streamflow scenario was used in a water resources system model that simulated current and predicted future performance of the system. The progressive warming of the PCM scenarios (approximately 1.2 °C at midcentury, and 2.2 °C by the 2090s), coupled with reductions in winter and spring precipitation (from 10 to 25%), markedly reduced late spring snowpack (by as much as half on average by the end of the century). Progressive reductions in winter, spring, and summer streamflow were less severe in the northern part of the study domain than in the south, where a seasonality shift was apparent. Results from the water resources system model indicate that achieving and maintaining status quo (control scenario climate) system performance in the future would be nearly impossible, given the altered climate scenario hydrologies. The most comprehensive of the mitigation alternatives examined satisfied only 87–96% of environmental targets in the Sacramento system, and less than 80% in the San Joaquin system. It is evident that demand modification and system infrastructure improvements will be required to account for the volumetric and temporal shifts in flows predicted to occur with future climates in the Sacramento–San JoaquinRiver basins.  相似文献   

Mass consistent models for wind distribution in complex terrain — Fast algorithms for three dimensional problems     

Nathan Dinar 《Boundary-Layer Meteorology》1984,30(1-4):177-199

Mass consistent models for wind distribution in complex terrain are extremely useful and readily applied to many practical situations, such as the siting of wind turbines, or as input in the estimation of diffusion and transport of pollutants in complex terrain. These models are based on the numerical solution of the steady state three dimensional continuity equation for the mean wind components. The momentum and energy equations are not solved explicitly, but considered indirectly using parametric relations and wind data. In practical applications the equations must be solved numerous times (e.g. for each time interval). Standard techniques for numerical solution of three dimensional problems are frequently very expensive and thus not suitable for practical needs. In the present work, great emphasis is given to the development of fast algorithms, and techniques based on the multigrid approach are shown. Two mass consistent programs are described, the first based on the parametric representation of one of the wind components, and the second based on a few wind measurements and a variational principle. To verify the reliability of the variational approach, a measurement program related to a project of wind energy, is being performed at Har-Ahim, a site located in the Galilee.  相似文献   

Groundwater Depletion and Agricultural Land Use Change in the High Plains: A Case Study from Wichita County,Kansas*     

Nathan Kettle  Lisa Harrington  John Harrington Jr. 《The Professional geographer》2007,59(2):221-235

Shifts in resource availability and resulting land use changes are important research themes for coupled human and natural systems and human dimensions of global environmental change. This study examines the relationship between groundwater depletion and agricultural land use change within a single county in the High Plains, where agro-economic systems and populations are dependent on access to reliable groundwater supplies. Results indicate a significant relationship between high proportionate decreases in groundwater and land being removed from irrigation. This case study strengthens the links among local, regional, and global environmental change, and contributes to a greater understanding of the High Plains in the context of regional sustainability and vulnerability concerns.  相似文献   

Vertical-axis rotation controlled by upper crustal stress based on force balance analysis: A case study of the western Transverse Ranges of California     

Nathan W. Onderdonk   《Tectonophysics》2007,436(1-4):1-8

This paper evaluates driving mechanisms of vertical-axis rotation using data from the western Transverse Ranges in southern California. Simple force balance considerations and comparison of torque applied to a rotating block indicate that shear forces applied to the base of the block are not strong enough to produce the motions and deformation observed at the surface. For the measured dimensions of the crustal blocks and crustal viscosities in southern California, stresses transmitted through the upper crust are one to three orders of magnitude stronger than forces generated in the ductile lower crust. These results suggest that the kinematics of crustal blocks in continental deformation zones are primarily controlled by forces within the upper crust rather than a flow field beneath.  相似文献   

An improved practical approach for estimating catchment-scale response functions through wavelet analysis     

Ravindra Dwivedi  Christopher Eastoe  John F. Knowles  Lejon Hamann  Thomas Meixner  Paul A. “Ty” Ferre  Christopher Castro  William E. Wright  Guo-Yue Niu  Rebecca Minor  Greg A. Barron-Gafford  Nathan Abramson  Bhaskar Mitra  Shirley A. Papuga  Michael Stanley  Jon Chorover 《水文研究》2021,35(3):e14082

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Heat tracing of heterogeneous hyporheic exchange adjacent to in‐stream geomorphic features     

Laura K. Lautz  Nathan T. Kranes  Donald I. Siegel 《水文研究》2010,24(21):3074-3086

There are many field techniques used to quantify rates of hyporheic exchange, which can vary in magnitude and direction spatially over distances of only a few metres, both within and between morphological features. We used in‐stream mini‐piezometers and heat transport modelling of stream and streambed temperatures to quantify the rates and directions of water flux across the streambed interface upstream and downstream of three types of in‐stream geomorphic features: a permanent dam, a beaver dam remnant and a stream meander. We derived hyporheic flux estimates at three different depths at six different sites for a month and then paired those flux rates with measurements of gradient to derive hydraulic conductivity (K) of the streambed sediments. Heat transport modelling provided consistent daily flux estimates that were in agreement directionally with hydraulic gradient measurements and also identified vertical heterogeneities in hydraulic conductivity that led to variable hyporheic exchange. Streambed K varied over an order of magnitude (1·9 × 10^?6 to 5·7 × 10^?5 m/s). Average rates of hyporheic flux ranged from static (q < ±0·02 m/day) to 0·42 m/day. Heat transport modelling results suggest three kinds of flow around the dams and the meander. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

A simple carbon cycle representation for economic and policy analyses     

Michael J. Glotter  Raymond T. Pierrehumbert  Joshua W. Elliott  Nathan J. Matteson  Elisabeth J. Moyer 《Climatic change》2014,126(3-4):319-335

Integrated Assessment Models (IAMs) that couple the climate system and the economy require a representation of ocean CO₂ uptake to translate human-produced emissions to atmospheric concentrations and in turn to climate change. The simple linear carbon cycle representations in most IAMs are not however physical at long timescales, since ocean carbonate chemistry makes CO₂ uptake highly nonlinear. No linearized representation can capture the ocean’s dual-mode behavior, with initial rapid uptake and then slow equilibration over ∽10,000 years. In a business-as-usual scenario followed by cessation of emissions, the carbon cycle in the 2007 version of the most widely used IAM, DICE (Dynamic Integrated model of Climate and the Economy), produces errors of ∽2^°C by the year 2300 and ∽6^°C by the year 3500. We suggest here a simple alternative representation that captures the relevant physics and show that it reproduces carbon uptake in several more complex models to within the inter-model spread. The scheme involves little additional complexity over the DICE model, making it a useful tool for economic and policy analyses.  相似文献   

Integrated assessment of smallholder farming’s vulnerability to drought in the Brazilian Semi-arid: a case study in Ceará   总被引：1，自引：0，他引：1  

Diego Pereira Lindoso  Juliana Dalboni Rocha  Nathan Debortoli  Izabel Ibiapina Parente  Flávio Eiró  Marcel Bursztyn  Saulo Rodrigues-Filho 《Climatic change》2014,127(1):93-105

Smallholder farming is among the most vulnerable sectors due to its great social and economic sensitivity. Despite future climate change, current climate variability is already an issue of concern that justifies adaptation efforts. In Brazil, the Semi-Arid Region is a climate hotspot, well known for both historic socioeconomic setbacks, and agriculture failures caused by dry spells and severe droughts. In 2010, the Brazilian government enacted the National Policy on Climate Change, which states as one of its key goals the identification of vulnerabilities and the adoption of adequate measures of adaptation to climate change. The improvement of vulnerability assessment tools is a response to the growing demand of decision makers for regular information and indicators with high spatial and temporal resolution. This article aims at undertaking a comparative assessment of smallholder farming’s vulnerability to droughts. An integrated assessment system has been developed and applied to seven municipalities located in the Brazilian Semi-Arid Region (within the State of Ceará). Results show regional vulnerability contrasts driven by institutional and socioeconomic factors, beyond climatic stressors.  相似文献   

Climate extremes in the United States: recent research by physical geographers     

David Retchless  Nathan Frey  Chongming Wang  Li-San Hung 《自然地理学》2014,35(1):3-21

This paper reports our review of research on domestic climate extremes conducted by US physical geographers over the past 15?years. Sections cover extremes in wind, precipitation, lightning, and temperature, as well as derivative climate extremes (droughts, floods, and storm surges). Themes considered include: the spatial and temporal distribution of the climate extreme; its implications for our understanding of the physical processes that produce it; the spatial and temporal distributions of the extreme’s economic and human costs; lessons for assessment, policy, and management; and scale. We conclude that most of the works reviewed inadequately address the human basis of vulnerability to climate extremes, and encourage physical geographers to work with colleagues from the other subfields of geography and the social sciences to develop the holistic understanding of vulnerability needed to effectively adapt to the more extreme climate projected under climate change.  相似文献