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221.
222.
From Global to Local: Providing Actionable Flood Forecast Information in a Cloud‐Based Computing Environment 下载免费PDF全文
J. Fidel Perez Nathan R. Swain Herman G. Dolder Scott D. Christensen Alan D. Snow E. James Nelson Norman L. Jones 《Journal of the American Water Resources Association》2016,52(4):965-978
Global and continental scale flood forecast provide coarse resolution flood forecast, but from the perspective of emergency management, flood warnings should be detailed and specific to local conditions. The desired refinement can be provided by the use of downscaling global scale models and through the use of distributed hydrologic models to produce a high‐resolution flood forecast. Three major challenges associated with transforming global flood forecasting to a local scale are addressed in this work. The first is using open‐source software tools to provide access to multiple data sources and lowering the barriers for users in management agencies at local level. This can be done through the Tethys Platform that enables web water resources modeling applications. The second is finding a practical solution for the computational requirements associated with running complex models and performing multiple simulations. This is done using Tethys Cluster that manages distributed and cloud computing resources as a companion to the Tethys Platform for web app development. The third challenge is discovering ways to downscale the forecasts from the global extent to the local context. Three modeling strategies have been tested to address this, including downscaling of coarse resolution global runoff models to high‐resolution stream networks and routing with Routing Application for Parallel computatIon of Discharge (RAPID), the use of hierarchical Gridded Surface and Subsurface Hydrologic Analysis (GSSHA) distributed models, and pre‐computed distributed GSSHA models. 相似文献
223.
Recent developments of safer formulations
of agrochemicals 总被引:2,自引:0,他引:2
Alan Knowles 《The Environmentalist》2008,28(1):35-44
The primary objectives of formulation technology are to optimise the biological activity of the pesticide, and to give a product
which is safe and convenient for use. However, because of the wide variety of pesticide active ingredients which are available,
many different types of formulations have been developed depending mainly on the physico-chemical properties of the active
ingredients. In the past most formulations were based on simple solutions in water (SL), emulsifiable concentrates in a petroleum-based
solvent (EC), or dusts (DP) and wettable powders (WP). The presence of petroleum-based solvents in EC formulations and dusty
powders in DP and WP formulations can lead to safety hazards in use and a negative impact on the envirnoment generally. Most
government and regulatory authorities are now demanding formulations which are cleaner and safer for the user, have minimal
impact on the environment, and can be applied at the lowest dose rate. Developments in formulation technology and novel formulation
types, sometimes in special packaging such as water-soluble packs, can also give products a competitive advantage, add value
or extend the lif-cycle of active ingredients. There is also a demand from government authorities and consumer groups to use
safer formulation additives and adjuvants, and to minimise the residues of pesticides on food crops after spraying. All of
these aspects are putting increasing pressure on the development of improved formulation and adjuvant technologies. Pesticide
formulations for spray application and for seed treatment are discussed, along with developments in bioenchancement. 相似文献
224.
Timothy M. Barzyk Barbara Jane George Alan F. Vette Ronald W. Williams Carry W. Croghan Carvin D. Stevens 《Atmospheric environment (Oxford, England : 1994)》2009,43(4):787-797
The primary objective of the Detroit Exposure and Aerosol Research Study (DEARS) was to compare air pollutant concentrations measured at various neighborhoods, or exposure monitoring areas (EMAs), throughout a major metropolitan area to levels measured at a central site or community monitor. One of the EMAs was located near a busy freeway (annual average daily traffic (AADT) of ~130,000) so that impacts of mobile sources could be examined. Air pollution concentrations from the roadway-proximate sites were compared to the central site monitor. The volatile organic compounds (VOCs) selected (benzene, toluene, ethylbenzene, m,p- and o-xylene, 1,3 butadiene, 1,3,5-trimethylbenzene and 4-ethyltoluene) are typically associated with mobile sources. Gradients were also evident that demonstrated the amplification of pollutant levels near the roadway compared to the community monitor. A novel distance-to-roadway proximity metric was developed to plot the measurements and model these gradients. Effective distance represents the actual distance an air parcel travels from the middle of a roadway to a site and varies as a function of wind direction, whereas perpendicular distance is a fixed distance oriented normal to the roadway. Perpendicular distance is often used as a proxy for exposures to traffic emissions in epidemiological studies.Elevated concentrations of all the compounds were found for both a summer and winter season. Effective distance was found to be a statistically significant (p < 0.05) univariate predictor for concentrations of toluene, ethylbenzene, m,p-xylene and o-xylene for summer 2005. For each of these pollutants, effective distance yielded lower p-values than the corresponding perpendicular distance models, and model fit improved. Results demonstrate that this near-road EMA had elevated levels of traffic-related VOCs compared to the community monitor, and that effective distance was a more accurate predictor of the degree to which they were elevated as a function of distance. Effective distance produced a range of distance-to-roadway values for a single site based on wind direction, thus increasing the number and range of values that could be used to plot and predict relative differences in pollutant concentrations between two sites. 相似文献
225.
Neufeld HS Peoples SJ Davison AW Chappelka AH Somers GL Thomley JE Booker FL 《Environmental pollution (Barking, Essex : 1987)》2012,160(1):74-81
Ozone-sensitive and -tolerant individuals of cutleaf coneflower (Rudbeckia laciniata L.) were compared for their gas exchange characteristics and total non-structural carbohydrates at Purchase Knob, a high elevation site in Great Smoky Mountains National Park, USA. Photosynthesis and stomatal conductance decreased with increased foliar stipple. Sensitive plants had lower photosynthetic rates for all leaves, except the very youngest and oldest when compared to tolerant plants. Stomatal conductance decreased with increasing leaf age, but no ozone-sensitivity differences were found. Lower leaves had less starch than upper ones, while leaves on sensitive plants had less than those on tolerant plants. These results show that ambient levels of ozone in Great Smoky Mountains National Park can adversely affect gas exchange, water use efficiency and leaf starch content in sensitive coneflower plants. Persistence of sensitive genotypes in the Park may be due to physiological recovery in low ozone years. 相似文献
226.
Sundström M Bogdanska J Pham HV Athanasios V Nobel S McAlees A Eriksson J DePierre JW Bergman Å 《Chemosphere》2012,87(8):865-871
Here, we describe for the first time the synthesis of [35S] PFOS and [35S] PFBS with sulfur-35 enriched sulfur dioxide as the radiolabelled reagent, resulting in 2.5 and 2.3 mCi of product, respectively. Basic information concerning the physicochemical properties of perfluorooctanesulfonate (PFOS), perfluorobutanesulfonate (PFBS) and perfluorooctanoic acid (PFOA) are still limited. Hence, we utilized these radiolabelled perfluoroalkanesulfonates (PFSAs), as well as carbon-14 labelled perfluorooctanoic acid ([14C] PFOA) to determine some basic characteristics of physiological and experimental significance.The solubility of PFOS in buffered aqueous solutions at pH 7.4 was found to be severely reduced in the presence of potassium and sodium ions, which, however, did not reduce the solubility of PFOA or PFBS. PFOS was found to adhere to a small extent to polypropylene and polystyrene, whereas no such adhesion of PFOA or PFBS was detected. The extents of adhesion of PFOS and PFOA to glass were found to be 20% and 10%, respectively. For the first time, the partition coefficients for PFOS, PFBS and PFOA between n-octanol and water were determined experimentally, to be −0.7, −0.3, and 1.4, respectively, reflecting the difference in the amphiphilic natures of these molecules. 相似文献
227.
Swain EB Jakus PM Rice G Lupi F Maxson PA Pacyna JM Penn A Spiegel SJ Veiga MM 《Ambio》2007,36(1):45-61
In the past, human activities often resulted in mercury releases to the biosphere with little consideration of undesirable consequences for the health of humans and wildlife. This paper outlines the pathways through which humans and wildlife are exposed to mercury. Fish consumption is the major route of exposure to methylmercury. Humans can also receive toxic doses of mercury through inhalation of elevated concentrations of gaseous elemental mercury. We propose that any effective strategy for reducing mercury exposures requires an examination of the complete life cycle of mercury. This paper examines the life cycle of mercury from a global perspective and then identifies several approaches to measuring the benefits of reducing mercury exposure, policy options for reducing Hg emissions, possible exposure reduction mechanisms, and issues associated with mercury risk assessment and communication for different populations. 相似文献
228.
Environmental Management - The population in the American West has been increasing at a rapid rate and is predicted to continue growing. As a result, the availability, use, and allocation of water... 相似文献
229.
With the adoption of the Berlin Mandate, developed countries are being asked to set emission limits for the early decades of the next century. The size of the reductions is currently the subject of international negotiations. This paper is intended to contribute to the analysis and assessment phase leading up to the adoption of new targets and timetables. However, we take a somewhat different approach than that suggested by the Berlin Mandate. Rather than focus exclusively on the next steps by developed countries, we view the issue from the perspective of the Convention's ultimate objective, the stabilization of atmospheric concentrations. We examine what might constitute costeffective strategies for limiting CO2 concentrations to alternative levels. We then explore the implications for nearterm mitigation decisions and for longterm participation by the developing countries. 相似文献
230.
Leanne E. Atwater Shelley D. Dionne John F. Camobreco Bruce J. Avolio Alan Lau 《组织行为杂志》1998,19(6):559-576
This study examined attributes of leaders that influenced their use of contingent and noncontingent punishment and the results of using punishment on leader effectiveness. Results indicated that leaders with higher levels of physical fitness and moral reasoning were more likely to use contingent punishment, while those with lower self-esteem were more likely to use noncontingent punishment. Noncontingent punishment negatively impacted leader effectiveness, while contingent punishment positively impacted leader effectiveness. © 1998 John Wiley & Sons, Ltd. 相似文献