135 research outputs found
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On the Sensitivity of Atmospheric Model Implied Ocean Heat Transport to the Dominant Terms of the Surface Energy Balance
The oceanic meridional heat transport (T{sub o}) implied by an atmospheric General Circulation Model (GCM) can help evaluate a model's readiness for coupling with an ocean GCM. In this study we examine the T{sub o} from benchmark experiments of the Atmospheric Model Intercomparison Project, and evaluate the sensitivity of T{sub o} to the dominant terms of the surface energy balance. The implied global ocean TO in the Southern Hemisphere of many models is equatorward, contrary to most observationally-based estimates. By constructing a hybrid (model corrected by observations) T{sub o}, an earlier study demonstrated that the implied heat transport is critically sensitive to the simulated shortwave cloud radiative effects, which have been argued to be principally responsible for the Southern Hemisphere problem. Systematic evaluation of one model in a later study suggested that the implied T{sub o} could be equally as sensitive to a model's ocean surface latent heat flux. In this study we revisit the problem with more recent simulations, making use of estimates of ocean surface fluxes to construct two additional hybrid calculations. The results of the present study demonstrate that indeed the implied T{sub o} of an atmospheric model is very sensitive to problems in not only the surface net shortwave, but the latent heat flux as well. Many models underestimate the shortwave radiation reaching the surface in the low latitudes, and overestimate the latent heat flux in the same region. The additional hybrid transport calculations introduced here could become useful model diagnostic tests as estimates of implied ocean surface fluxes are improved
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Radionuclide air emissions report for the Hanford site calendar year 1995
This report documents radionuclide air emissions from the Hanford Site in 1995, and the resulting effective dose equivalent (FDE) to the maximally exposed member of the public, referred to as the `MEI.` The report has been prepared and will be submitted in accordance with reporting requirements in the Code of Federal Regulations, Title 40, Protection of the Environment, Part 61, `National Emissions Standards for Hazardous Air Pollutants,` Subpart H, `National Emission Standards for Emissions of Radionuclides Other than Radon from Department of Energy Facilities.` This report has also been prepared for and will be submitted in accordance with the reporting requirements of the Washington Administrative Code Chapter 246-247, `Radiation Protection-Air Emissions.
Survey of Wholesale and Retail Buyers in the Six Southern States of the North Central Region
Technology has improved production of aquaculture products and reduced unit costs such that reasonably dependable supplies of fish and seafood are available to the markets. This study describes current distribution channels at the wholesale and retail levels for farm-raised and wild-caught species in the North Central Region (NCR), and evaluates both buyer attitudes towards farm-raised products and interest in specific species. Suppliers of fish and seafood products are experiencing a growth in consumer demand. United States per capita consumption of edible fish and seafood increased from 12.8 pounds in 1980 to 15.9 pounds in 1989, and is expected to reach more than 20 pounds per capita by the year 2000 (U.S. Department of Commerce 1990). This is attributed to increased average income, changing consumer demographics, and the present wave of health consciousness (Blaylock et al. 1987). As “Baby Boomers” approach middle age and the number of senior citizens increase, the health benefits derived from eating fish are becoming important issues
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Final report of fugitive and diffuse emissions evaluations at the Hanford Site, CY 1994
The objective of this study was to evaluate several of Hanford`s major diffuse emission sources and evaluate the effectiveness of monitoring these sources individually versus collectively. The results from this evaluation may also be utilized to demonstrate Westinghouse`s compliance status with the applicable air emissions regulations and determine if additional studies and/or evaluations are necessary. Air sampling results from four waste handling and storage facilities were collected for a one week period and analyzed. The following is a list of the selected sampling sites: Plutonium Finishing Plant; 241-BY Tank Farm; 1301-N Trench; 300 Area Trenches and North Ponds. These sites were chosen as being representative of most of the Hanford waste sites, which are known to be diffuse emission sites. The sites were evaluated on the following criteria: physical size, surface contamination levels, geology, vegetation density, surface cover, potential for occupational exposure, and potential for public exposure. The selected sites vary greatly with the selection criteria parameters, and as a result should provide representative data for most of Hanford`s waste sites
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1995 Study and evaluation of fugitive and diffuse emissions from the 200 East Area at the Hanford Site
The objective of this study is to evaluate Hanford`s major diffuse emission sources in the 200 East Area and evaluate the effectiveness of monitoring these sources collectively. The results from this evaluation may also be utilized to demonstrate Westinghouse`s compliance status with the applicable air emissions regulations and determine if additional studies and/or evaluations are necessary. Air sampling will be conducted downwind of the 200 East Area. This site has been chosen as being representative of most large diffuse sources located on the Hanford waste sites. A review of the 1993 ambient air data indicated that {sup 137}C was detectable in this area. This study will take place during February to August of 1995. This time period will enable the collection of sufficient data to assess diffuse radionuclide emissions from the 200 East Area waste sites. This study will use existing ambient air monitoring stations supplemented with temporary air monitoring stations. Plots of the 1993 average concentrations of {sup 137}Cs and {sup 90}Sr collected from the existing stations may be found in Appendix A. Upon completion of this evaluation a recommendation will be made to perform additional sampling studies, or to discontinue further data gathering based on the evaluation`s results
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Diffuse and fugitive emission dose assessment on the Hanford Site
On February 3, 1993, the US Department of Energy, Richland Operations Office (RL), received a Compliance Order and Information Request from the Director of the Air and Toxics Division of the US Environmental Protection Agency (EPA), Region 10. The Compliance Order requires RL to (1) evaluate all radionuclide emission points at the Hanford Site to determine which are subject to continuous emission measurement requirements in 40 Code of Federal Regulations (CFR) 61, Subpart H, and (2) continuously measure radionuclide emissions in accordance with 40 CFR 61.93. The Information Request requires RL to provide a written Compliance Plan to meet the requirements of the Compliance Order. The RL Compliance Plan included as one of its milestones the requirement to develop a Federal Facility Compliance Agreement (FFCA). An FFCA was negotiated between RL and the EPA, Region 10, and was entered into on February 7, 1994. One of the milestones was to provide EPA, Region 10, with a copy of the Federal Clean Air Act Title V operating air permit application and Air Emission Inventory (AEI) concurrent with its submission to the Washington State Department of Ecology. The AEI will include an assessment of the diffuse and fugitive emissions from the Hanford Site. This assessment does not identify any diffuse or fugitive emission source that would cause an effective dose equivalent greater than 0.1 mrem/yr
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Secular Trends and Climate Drift in Coupled Ocean-Atmosphere General Circulation Models
Coupled ocean-atmosphere general circulation models (coupled GCMs) with interactive sea ice are the primary tool for investigating possible future global warming and numerous other issues in climate science. A long-standing problem with such models is that when different components of the physical climate system are linked together, the simulated climate can drift away from observations unless constrained by ad hoc adjustments to interface fluxes. However, eleven modern coupled GCMs--including three that do not employ flux adjustments--behave much better in this respect than the older generation of models. Surface temperature trends in control run simulations (with external climate forcing such as solar brightness and atmospheric carbon dioxide held constant) are small compared with observed trends, which include 20th century climate change due to both anthropogenic and natural factors. Sea ice changes in the models are dominated by interannual variations. Deep ocean temperature and salinity trends are small enough for model control runs to extend over 1000 simulated years or more, but trends in some regions, most notably the Arctic, are inconsistent among the models and may be problematic
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Krakatau's long goodbye in the Ocean
State-of-the-art climate models suggest that 20th Century ocean warming and sea-level rise were substantially reduced by the 1883 eruption of Krakatau. Volcanically induced cooling of the ocean surface penetrated into deeper layers where it persisted for decades. We find that volcanic eruptions have longer lasting effects than previously suspected, sufficient to offset a large fraction of ocean warming and sea-level rise caused by anthropogenic influences over the 20th Century. We examine the latest suite of coupled ocean-atmosphere model experiments that include time-varying external forcings (e.g., changes in greenhouse gases, solar irradiance, sulfate aerosols and volcanic aerosols) for the period 1880-2000 (see Methods). These models have differences in physics, resolution, initial conditions, 'spin-up' and ocean-atmosphere coupling procedures, as well as different combinations of external forcings. Uncertainties in both the applied forcings and in the model responses to them are therefore inherent in our investigation
On the use and misuse of climate change projections in international development
Climate resilience is increasingly prioritized by international development agencies and national governments. However, current approaches to informing communities of future climate risk are problematic. The predominant focus on end-of-century projections neglects more pressing development concerns, which relate to the management of shorter-term risks and climate variability, and constitutes a substantial opportunity cost for the limited financial and human resources available to tackle development challenges. When a long-term view genuinely is relevant to decisionmaking, much of the information available is not fit for purpose. Climate model projections are able to capture many aspects of the climate system and so can be relied upon to guide mitigation plans and broad adaptation strategies, but the use of these models to guide local, practical adaptation actions is unwarranted. Climate models are unable to represent future conditions at the degree of spatial, temporal, and probabilistic precision with which projections are often provided, which gives a false impression of confidence to users of climate change information. In this article, we outline these issues, review their history, and provide a set of practical steps for both the development and climate scientist communities to consider. Solutions to mobilize the best available science include a focus on decision-relevant timescales, an increased role for model evaluation and expert judgment and the integration of climate variability into climate change service
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