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11.
Social scientists have debated how affluence impacts carbon emissions at the national level. We conduct an exploratory study at the subnational level to expose another dimension of the affluence–emissions debate. Based on the notion of aristocratic conservation, we hypothesize that affluence is positively related to carbon emissions from consumption activities but negatively related to emissions from production activities. We test these hypotheses using county-level data in the United States for the year 2002. A spatial regression analysis demonstrates that median household income is positively associated with consumption-based emissions; nevertheless, we find evidence of an environmental inequality Kuznets curve in the relationship between median household income and production-based emissions. This finding suggests that the wealthiest counties are able to displace certain types of emissions, specifically those related to energy and industrial production. We discuss the theoretical and political implications of these results. 相似文献
12.
Geological maps of South Carolina, covering > 6800 km2, confirm the existence of eight preserved Pleistocene shorelines above current sea level: Marietta (+ 42.6 m), Wicomico (+ 27.4 m), Penholoway (+ 21.3 m), Ladson (+ 17.4 m), Ten Mile Hill (+ 10.7 m), Pamlico (+ 6.7 m), Princess Anne (+ 5.2 m), and Silver Bluff (+ 3 m). Current geochronologic data suggest that these eight shorelines correlate with Marine Oxygen Isotope Stages (MIS) as follows: Marietta—older than MIS 77; Wicomico—MIS 55–45; Penholoway—MIS 19 or 17; Ladson—MIS 11; Ten Mile Hill—MIS 7; Pamlico—MIS 5; Princess Anne—MIS 5; and Silver Bluff—MIS 5 or 3. Except for the MIS 5e Pamlico, and possibly the MIS 11 Ladson, the South Carolina elevations are higher than predicted by isotope proxy-based reconstructions. The < 4 m of total relief from the Pamlico to the Silver Bluff shoreline in South Carolina, for which other reconstructions suggest an expected relief of ~ 80 m, illustrates the lack of match. Our results suggest that processes affecting either post-depositional changes in shoreline elevations or the creation of proxy sea-level estimates must be considered before using paleo sea-level position on continental margins. 相似文献
13.
Barry H. Lynn Cynthia Rosenzweig Richard Goldberg David Rind Christian Hogrefe Len Druyan Richard Healy Jimy Dudhia Joyce Rosenthal Patrick Kinney 《Climatic change》2010,99(3-4):567-587
The Mesoscale Modeling System Version 5 (MM5) was one-way nested to the Goddard Institute for Space Studies global climate model (GISS GCM), which provided the boundary conditions for present (1990s) and future (IPCC SRES A2 scenario, 2050s) five-summer “time-slice” simulations over the continental and eastern United States. Five configurations for planetary boundary layer, cumulus parameterization, and radiation scheme were tested, and one set was selected for use in the New York City Climate and Health Project—a multi-disciplinary study investigating the effects of climate change and land-use change on human health in the New York metropolitan region. Although hourly and daily data were used in the health project, in this paper we focus on long-term current and projected mean climate change. The GISS-MM5 was very sensitive to the choice of cumulus parameterization and planetary boundary layer scheme, leading to significantly different temperature and precipitation outcomes for the 1990s. These differences can be linked to precipitation type (convective vs. non-convective), to their effect on solar radiation received at the ground, and ultimately to surface temperature. The projected changes in climate (2050s minus 1990s) were not as sensitive to choice of model physics combination. The range of the projected surface temperature changes at a given grid point among the model versions was much less than the mean change for all five model configurations, indicating relative consensus for simulating surface temperature changes among the different model projections. The MM5 versions, however, offer less consensus regarding 1990s to 2050s changes in precipitation amounts. All of the projected 2050s temperature changes were found to be significant at the 95th percent confidence interval, while the majority of the precipitation changes were not. 相似文献
14.
Impact of Terrain Heterogeneity on Coherent Structure Properties: Numerical Approach 总被引:2,自引:2,他引:0
Clement Fesquet Sylvain Dupont Philippe Drobinski Thomas Dubos Christian Barthlott 《Boundary-Layer Meteorology》2009,133(1):71-92
A three-dimensional large-eddy simulation (LES) model, which includes the effects of plant–atmosphere interactions, is used
to study the effects of surface inhomogeneities on near-surface coherent structures over an open field and behind a forest
canopy. These simulated conditions are representative of two wind sectors of the Site Instrumental de Recherche par Télédétection
Atmosphérique (SIRTA) experimental site at the Institut Pierre Simon Laplace, Palaiseau, France. Coherent structure properties
deduced from wavelet transforms of the simulated near-surface vertical velocity time series are not modified by upstream terrain
heterogeneities, in agreement with site measurements. This feature is related to the nature of structures detected from the
vertical velocity time series. The turbulence close to the surface seems composed of both local coherent structures and large
coherent structures reflecting outer-layer properties, which depend on the overall surface heterogeneity or upstream heterogeneity.
It is argued that the streamwise velocity is representative of these large outer-layer structures that impinge onto the ground
through a top-down mechanism as identified through the space–time correlation of the wind velocity components. In contrast,
the vertical velocity is more representative of small structures resulting from the impingement of the large outer-layer structures.
These small structures represent locally-generated, active turbulence, which adjusts rapidly to local surface conditions,
and consequently they are only weakly dependent on upstream heterogeneities. 相似文献
15.
Gregory J. Dick Brian G. Clement Samuel M. Webb John R. Bargar 《Geochimica et cosmochimica acta》2009,73(21):6517-6063
Microorganisms play important roles in mediating biogeochemical reactions in deep-sea hydrothermal plumes, but little is known regarding the mechanisms that underpin these transformations. At Guaymas Basin (GB) in the Gulf of California, hydrothermal vents inject fluids laden with dissolved Mn(II) (dMn) into the deep waters of the basin where it is oxidized and precipitated as particulate Mn(III/IV) oxides, forming turbid hydrothermal “clouds”. Previous studies have predicted extremely short residence times for dMn at GB and suggested they are the result of microbially-mediated Mn(II) oxidation and precipitation. Here we present biogeochemical results that support a central role for microorganisms in driving Mn(II) oxidation in the GB hydrothermal plume, with enzymes being the primary catalytic agent. dMn removal rates at GB are remarkably fast for a deep-sea hydrothermal plume (up to 2 nM/h). These rapid rates were only observed within the plume, not in background deep-sea water above the GB plume or at GB plume depths (∼1750-2000 m) in the neighboring Carmen Basin, where there is no known venting. dMn removal is dramatically inhibited under anoxic conditions and by the presence of the biological poison, sodium azide. A conspicuous temperature optimum of dMn removal rates (∼40 °C) and a saturation-like (i.e. Michaelis-Menten) response to O2 concentration were observed, indicating an enzymatic mechanism. dMn removal was resistant to heat treatment used to select for spore-forming organisms, but very sensitive to low concentrations of added Cu, a cofactor required by the putative Mn(II)-oxidizing enzyme. Extended X-ray absorption fine structure spectroscopy (EXAFS) and synchrotron radiation-based X-ray diffraction (SR-XRD) revealed the Mn oxides to have a hexagonal birnessite or δ-MnO2-like mineral structure, indicating that these freshly formed deep-sea Mn oxides are strikingly similar to primary biogenic Mn oxides produced by laboratory cultures of bacteria. Overall, these results reveal a vigorous Mn biogeochemical cycle in the GB hydrothermal plume, where a distinct microbial community enzymatically catalyzes rapid Mn(II) oxidation and the production of Mn biooxides. 相似文献
16.
A conceptual model of anisotropic and dynamic permeability is developed from hydrogeologic and hydromechanical characterization of a foliated, complexly fractured, crystalline rock aquifer at Gates Pond, Berlin, Massachusetts. Methods of investigation include aquifer‐pumping tests, long‐term hydrologic monitoring, fracture characterization, downhole heat‐pulse flow meter measurements, in situ extensometer testing, and earth tide analysis. A static conceptual model is developed from observations of depth‐dependent and anisotropic permeability that effectively compartmentalizes the aquifer as a function of foliation intensity. Superimposed on the static model is dynamic permeability as a function of hydraulic head in which transient bulk aquifer transmissivity is proportional to changes in hydraulic head due to hydromechanical coupling. The dynamic permeability concept is built on observations that fracture aperture changes as a function of hydraulic head, as measured during in situ extensometer testing of individual fractures, and observed changes in bulk aquifer transmissivity as determined from earth tides during seasonal changes in hydraulic head, with higher transmissivity during periods of high hydraulic head, and lower transmissivity during periods of relatively lower hydraulic head. A final conceptual model is presented that captures both the static and dynamic properties of the aquifer. The workflow presented here demonstrates development of a conceptual framework for building numerical models of complexly fractured, foliated, crystalline rock aquifers that includes both a static model to describe the spatial distribution of permeability as a function of fracture type and foliation intensity and a dynamic model that describes how hydromechanical coupling impacts permeability magnitude as a function of hydraulic head fluctuation. This model captures important geologic controls on permeability magnitude, anisotropy, and transience and therefor offers potentially more reliable history matching and forecasts of different water management strategies, such as resource evaluation, well placement, permeability prediction, and evaluating remediation strategies. 相似文献
17.
We propose a new class of inflationary models in which the scalar field potential governing inflation is generated by the same nonperturbative gauge dynamics that may lead to supersymmetry breaking. Such models satisfy constraints from cosmic microwave background measurements for natural values of the fundamental parameters in the theory. In addition, they have two particularly interesting characteristics: a “blue” spectrum of scalar perturbations, and an upper bound on the total amount of inflation possible. 相似文献
18.
陆面过程模式是气候模式和天气模式的核心组成部分之一.在土壤—植被—大气耦合模式(Soil-PlantAtmosphere Model,SPAM)的基础上,发展了新一代北京大学陆面过程模式PKULM(Peking University Land Model).本文首先介绍了PKULM的辐射传输、湍流输送、光合作用、土壤水热输送等过程的参数化方案;采用隐式迭代计算框架,发展并应用了一个快速的线性方程组求解算法,提高了模式计算稳定性;提出并使用了二分搜索算法计算气孔阻抗,避免了CLM(Community Land Model)等使用的迭代方法在干旱区不稳定的情况,提高了模式的适用性;采用水势为基础的土壤水分扩散方程,使模式能够模拟土壤饱和区的水分输送过程,为进一步与水文过程模式耦合奠定了基础;还发展了一个地表积水与径流过程的机理模型,提高了模式对地表水分平衡过程的模拟能力;最后,使用"中国西北干旱区陆—气相互作用观测试验"平凉站的资料对模式进行了检验并与NOAH(National Center for Environmental Prediction,Oregon State University,Air Force,and Hydrology Lab model)陆面过程模式的模拟结果进行了比较,结果表明PKULM能够较好地模拟西北半干旱区农田下垫面地气交换过程. 相似文献
19.
Søren Munch Kristiansen Jacob Clement Yde Teresa Gómez Bárcena Bjarne Holm Jakobsen Jesper Olsen Niels Tvis Knudsen 《Geografiska Annaler: Series A, Physical Geography》2013,95(2):97-108
Groundwater in front of warm‐based glaciers is likely to become a more integrated part of the future proglacial hydrological system at high latitudes due to global warming. Here, we present the first monitoring results of shallow groundwater chemistry and geochemical fingerprinting of glacier meltwater in front of a warm‐based glacier in Southeast Greenland (Mittivakkat Gletscher, 65° 41′ N, 37° 48′ W). The groundwater temperature, electrical conductivity and pressure head were monitored from August 2009 to August 2011, and water samples were collected in 2009 and analyzed for major ions and water isotopes (δD, δ18O). The 2 yrs of monitoring revealed that major outbursts of glacier water during the ablation season flushed the proglacial aquifer and determined the groundwater quality for the next 2–8 weeks until stable chemical conditions were reached again. Water isotope composition shows that isotopic fractionation occurs in both groundwater and glacier meltwater, but fractionation due to evaporation from near‐surface soil moisture prior to infiltration has the most significant effect. This study shows that groundwater in Low Arctic Greenland is likely to possess a combined geochemical and isotopic composition, which is distinguishable from other water sources in the proglacial environment. However, the shallow groundwater composition at a given time is highly dependent on major outbursts of glacier water in the previous months. 相似文献
20.