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In the Upper Colorado River Basin (UCRB), there is a deep reliance on seasonal snowpack for maintenance of water resources. The term “snow drought” has recently emerged to describe periods of anomalously low snowpack. Unique seasonal patterns in precipitation and temperature that drive snow drought can have distinct hydrologic signatures, and these relationships have not been carefully studied in the UCRB. Here we examine snow drought with a new classification scheme using peak snow water equivalent (SWE) and the ratio of basin-wide modeled peak SWE to accumulated (onset to peak) precipitation (SWE/P) that clusters snow drought years into three distinct groups—“warm,” “dry,” and “warm & dry”—that minimize within-group variance. Over the period 1916–2018, we identify 14 warm years ( P ¯  = 160 mm; SWE / P ¯  = 0.24), 24 dry years ( P ¯  = 117 mm; SWE / P ¯  = 0.35), and 21 warm & dry years ( P ¯  = 94 mm; SWE / P ¯  = 0.23). An elevation-based analysis reveals two distinct patterns: warm snow droughts see severe SWE reductions primarily at lower (<2600 m) elevations (65% at lower elevations, 37% overall), whereas “dry” scenarios exhibit a consistent reduction across all elevations (39% overall). Using naturalized streamflow data, we also differentiate snow droughts by their earlier streamflow timing and decreased peakedness (warm: 7 days, 2%; dry: 7 days, 2%; warm & dry: 13 days, 5%). This research provides new insights into snow drought patterns relevant for regional water management.  相似文献   

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In the Willamette River, OR, main channel temperatures can be too warm for cold water fishes, causing fish to concentrate in secondary channel features that provide thermal refugia. However, temperature regimes vary among and within features. Improved understanding of physical processes controlling thermal regimes is needed. This study developed a dimensionless index for assessment of thermal refugia on the upper Willamette River. The novel hyporheic insolation (HIN) index uses minimal field measurements to predict thermal refugia resulting from buffering. Continuous water temperature measurements at one side channel, eight alcoves, and six beaver ponds provided data to ground truth calculated in predictions. Water temperature records were first used to characterize stratification at sites. Calculation of the Richardson number, an index of stability, showed two well-mixed sites and 13 stratified sites. At stratified sites, calculated in values characterized the ratio of cooling flux from hyporheic discharge to heat flux from incoming solar radiation. As in increased, measured temperatures at sites decreased. Despite overall scatter, a logarithmic fit to bin-averaged in values showed R2 = 0.91. Calculations suggest that secondary channel features characterized by stratification and cool hyporheic discharge can provide thermal refugia. Accordingly, the HIN index may serve as a practical tool grounded in physical processes governing temperature across a floodplain.  相似文献   

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Wellbore integrity is one of the key performance criteria in the geological storage of CO2. It is significant in any proposed storage site but may be critical to the suitability of depleted oil and gas reservoirs that may have 10’s to 1000’s of abandoned wells. Much previous work has focused on Portland cement which is the primary material used to seal wellbore systems. This work has emphasized the potential dissolution of Portland cement. However, an increasing number of field studies (e.g., Carey et al., 2007), experimental studies (e.g., Kutchko et al., 2006) and theoretical considerations indicate that the most significant leakage mechanism is likely to be flow of CO2 along the casing–cement microannulus, cement–cement fractures, or the cement–caprock interface.In this study, we investigate the casing–cement microannulus through core-flood experiments. The experiments were conducted on a synthetic wellbore system consisting of a 5-cm diameter sample of cement that was cured with an embedded rectangular length of steel casing that had grooves to accommodate fluid flow. The experiments were conducted at 40 ° C and 14 MPa pore pressure for 394 h. During the experiment, 6.2 l of a 50:50 mixture of supercritical CO2 and 30,000 ppm NaCl-rich brine flowed through 10-cm of limestone before flowing through the 6-cm length cement–casing wellbore system. Approximately 59,000 pore volumes of fluid moved through the casing–cement grooves. Scanning electron microscopy revealed that the CO2–brine mixture impacted both the casing and the cement. The Portland cement was carbonated to depths of 50–250 μm by a diffusion-dominated process. There was very little evidence for mass loss or erosion of the Portland cement. By contrast, the steel casing reacted to form abundant precipitates of mixed calcium and iron carbonate that lined the channels and in one case almost completely filled a channel. The depth of steel corroded was estimated at 25– 30μm and was similar in value to results obtained with a simplified corrosion model.The experimental results were applied to field observations of carbonated wellbore cement by Carey et al. (2007) and Crow et al. (2009) to show that carbonation of the field samples was not accompanied by significant CO2–brine flow at the casing–cement interface. The sensitivity of standard-grade steel casing to corrosion suggests that relatively straight-forward wireline logging of external casing corrosion could be used as a useful indicator of flow behind casing. These experiments also reinforce other studies that indicate rates of Portland cement deterioration are slow, even in the high-flux CO2–brine experiments reported here.  相似文献   

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The six mainstem reservoirs in the Missouri River basin (MRB) are managed mainly to prevent flooding from snowmelt and heavy rainfall, a goal for which the interannual variabilities of precipitation ( P ), evapotranspiration ( ET ), and surface air temperature ( T air ) are vitally important. We tested the hypothesis that under the expected higher variability owing to global climate change, the months with the highest contributions to the interannual variability of P , ET , and T air in the MRB will remain unchanged and quantified likely temporal trends in these quantities. Using high-resolution, downscaled Coupled Model Intercomparison Project Phase 5 multi-model ensemble data sets, we compared the multi-year ratio of monthly and annual interannual variability and temporal trends in P , ET , and T air during 2011–2020 with three future decades. Results showed that the 6 months with the highest interannual variability in P and ET (April–September) are the same in all four decades. However, for T air , only 4 months (December–March) retain their status as highly variable throughout the four decades; September and October variability is exceeded by the variability in other months. This implies that, compared to P and ET , the cyclical change in the probabilities of T air in the MRB is less stable under future global climate change. This finding can be used to consider the need to alter existing strategies for reservoir release while minimizing the likelihood of aggravating flooding below the reservoirs.  相似文献   

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This study explores the relationship between electricity consumption, real gross domestic product per capita and carbon dioxide emissions in Zimbabwe. To achieve this, the study set off by examining the stationarity properties of the variables under review with the Zivot-Andrews (1992 Zivot, E., and D.W.K. Andrews. 1992. Further evidence on the great crash, the oil-price shock, and the unit-root hypothesis. Journal Of Business and Economic Statistics 10:251-270. doi: http://dx.doi.org/10.2307/1391541.[Taylor &; Francis Online], [Web of Science ®] [Google Scholar]) unit root test that accounts for a single structural break. Subsequently, Maki (2012 Maki, Daiki. 2012. “Tests for Cointegration Allowing for an Unknown Number of Breaks.” Economic Modelling 29 (5): 2011–15. https://doi.org/10.1016/J.ECONMOD.2012.04.022 [Google Scholar]) cointegration test, which accounts for multiple structural breaks, is applied for equilibrium relationship between the variables under review while the long run regression of dynamic ordinary least square (DOLS) is employed for long-run coefficients as estimation procedures. In order to account for the direction of causality flow, the Toda-Yamamoto (1995 Toda, H Y.., and Taku Yamamoto. 1995. Statistical inference in vector autoregressions with possibly integrated processes. Journal Of Econometrics 66 (1–2):22550. doi: 10.1016/0304-4076(94)01616-8.[Crossref], [Web of Science ®] [Google Scholar]) causality test is used for annual frequency data set spanning from 1971–2014. Empirical evidence from the Maki cointegration test shows that there exists a long-run equilibrium relationship between electricity consumption, carbon dioxide emissions and real gross domestic product per capita over the sampled period. The long-run regression suggests that there exist a positive statistically significant relationship between real income and electricity consumption. Thus, corroborating the electricity-led growth hypothesis. This result is supported by the causality test, as one-way causality is observed running from electricity consumption to real gross domestic product. Thus, this is suggestive to government administrators and policymakers that the Zimbabwean economy is electricity dependent. However, there is a tradeoff for environmental quality. As the increase in electricity consumption increases carbon dioxide emissions. The need for diversification of Zimbabwe energy portfolio to cleaner and environmentally friendly energy sources is recommended, given the world global consciousness for cleaner energy consumption.  相似文献   

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The portrayal of animals in the media is often criticised for instrumentalising, objectifying and anthropomorphising animals (e.g. Hirschman and Sanders in Semiotica 115(1/2):53–79, 1997; Lerner and Kalof in Sociol Q 40(4):565–586, 1999; Stewart and Cole in Int J Multidiscip Res 12(4):457–476, 2009). Although we agree with this criticism, we also identify the need for a more substantiated approach to the moral significance of instrumentalisation, objectification and anthropomorphism. Thus, we propose a new framework which is able to address the morally relevant aspects of animal portrayal in the media. We closely examine the normative messages communicated by an unusual TV commercial in which an anthropomorphised piglet advertises organic beef. This serves as a case example to relate the philosophical and ethical concepts of objectification and anthropomorphism to each other and show how they can be applied. We conclude that the commercial conveys a message of animal instrumentalisation as being normatively correct within the constraint of good animal welfare. The depicted form of instrumentalisation is, nonetheless, associated with harm for the animals and thus, needs to overcome cognitive dissonance. To achieve this, animals are directly objectified by a trivialised and de-individualised portrayal. Moreover, animals are indirectly objectified even when they are anthropomorphised as they are granted significance only through being human-like. Thus, objectification and anthropomorphism are not opposing terms in our proposed framework. In addition, objectification, together with the reference to the dominant ideology, and combined with humorous anthropomorphism weakens scrutiny of these normative messages by the viewers. This eventually augments a decrease of moral concern for farmed animals in advertisement employing such portrayals.  相似文献   

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While the contemporary biomimicry movement is associated primarily with the idea of taking Nature as model for technological innovation, it also contains a normative or ethical principle—Nature as measure—that may be treated in relative isolation from the better known principle of Nature as model. Drawing on discussions of the principle of Nature as measure put forward by Benyus (Biomimicry: innovation inspired by nature, Harper Perennial, New York, 1997) and Jackson (Consulting the genius of place: an ecological approach to a new agriculture, Counterpoint, Berkeley, 2010, Nature as measure: the selected essays of Wes Jackson, Counterpoint, Berkeley, 2011), while at the same time situating these discussions in relation to contemporary debates in the philosophy of biomimicry (Mathews in Organ Environ 24(4): 364–387, 2011; Dicks in Philos Technol, doi: 10.1007/s13347-015-0210-2, 2015; Blok and Gremmen in J Agric Environ Ethics 29(2):203–217, 2016), the aim of this paper is to explore the relation between the principle of Nature as measure and environmental ethics. This leads to the argument that mainstream formulations of environmental ethics share the common trait of seeing our ethical relation to Nature as primarily involving duties to protect, preserve, or conserve various values in Nature, and that, in doing so, they problematically either overlook or dismiss as anthropocentric the possibility that Nature may provide measures, understood in terms of ecological standards, against which our own practices, or at least some of them, may be judged—a way of thinking I call “biomimetic ethics”. The practical consequences of this argument are significant. Whereas mainstream environmental ethics has been applied above all to such issues as wilderness preservation, natural resource management, and animal rights and welfare, biomimetic ethics is applicable rather to the question of how we produce, use, and consume things, and, as such, may potentially provide the basic ethical framework required to underpin the transition to a circular, bio-based, solar economy.  相似文献   

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This paper describes a GIS-based estimation method that can be used to forecast future amounts of impervious surface as a mitigation measure for urban heat island effect in a metropolitan region. The method is unique because it employs a regression model that links the existing amount of impervious surface to population and employment at the census tract level. This approach provides a means to forecast future amounts of impervious surface based on projected population and employment. The method also includes a detailed analysis of high-resolution aerial photography to divide impervious surfaces into different categories. Subdividing impervious surfaces is necessary to evaluate potential urban heat island mitigation policies for different types of impervious surface. The analysis here shows that the impervious surface in the metropolitan Atlanta region will increase to 2638 km2 2. “The Albedo is defined as the hemispherical reflectivity averaged over the solar spectrum. A perfect reflector has a = 1, and a perfect absorber has a = 0” (Pomerantz et al. 1999 Pomerantz, M. 1999. Reflective surfaces for cooler buildings and cities. Philosophical magazine B, 79: 14571476. [Taylor & Francis Online], [Web of Science ®] [Google Scholar], p. 1458). View all notes in 2030, an increase of 45% from 2000. The most common type of impervious surface is dark-coloured pavement. Within this study area, the analyses showed that two-thirds of impervious surfaces are dark. Replacing dark pavement with light pavement materials, therefore, represents an important opportunity to mitigate the urban heat island effect in the Atlanta region.  相似文献   

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This paper describes the frustrating reality of sustainability implementation in the USA and New Zealand (NZ), an early adopter of sustainability mandates. Local government has a key role in implementation, but has been slow to uptake sustainable practices. We surveyed senior planners in small to medium-sized local government agencies in both countries to identify which features of local government support (or hinder) sustainability in practice.

Environmentally sustainable practices are not well entrenched in either country. In the USA, the framing of sustainability and public support are significant predictors of implementation. However, sustainability is rarely a priority. In NZ, local government capacity is the main driver of implementation. We recommend that planners promote sustainability values, reconcile economic development goals with sustainability (e.g., green economy model), and translate public support for sustainability into institutional priorities. NZ localities also need increased capacity and US localities need continued Federal and State support.  相似文献   


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