2,049 research outputs found

    Effects of diabatic heating on the ageostrophic circulation of an upper tropospheric jet streak

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    Interaction between the mass circulation within a mesoscale convective complex (MCC) and a direct mass circulation in the entrance region of an upper tropospheric polar jet streak was examined within the isentropic structure to investigate mechanisms responsible for linking these two scales of motion. The results establish that latent heating in the MCC modifies the direct mass circulation in the jet streak entrance region through the diabatically induced components of ageostrophic motion analyzed within isentropic coordinates. Within the strong mesoscale mass circulation of each MCC, strong horizontal mass flux convergence into the MCC at low levels is balanced by strong horizontal mass flux divergence away from the convergence at upper levels. Locations of large diabatic heating rates correspond well to the MCC position for each case; diabatic heating forces the upward vertical branch for the mesoscale mass circulation

    Biodiversity—The Birds and the Bees and Healthy Grasslands

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    Losses in biodiversity abound in modern agroecosystems, and biodiversity loss hampers ecosystem function and primary productivity comparable to abiotic stress. One of the most endangered ecosystems in the world is North American tallgrass prairie, and native birds and pollinators that historically depended on tallgrass prairie are in precipitous decline. Fortunately, native warm-season grasses that dominated tallgrass prairie present a valuable opportunity for summer forage to beef producers in the Eastern United States—a time when coolseason grasses endure a lack in productivity called the “summer slump.” Tallgrass prairie was sustained by periodic disturbance from grazing and fire, and combining fire and grazing to manage native warm-season grasslands creates greater landscape heterogeneity than grazing of cool-season grasslands alone. As a result, native warm-season grasslands can support a wide variety of native grassland birds and pollinators while providing nutritious summer forage for beef production. Ultimately, establishing native warm-season grasslands on beef producer farms offers synergy between conservation and farm productivity that can translate to farm profitability

    Assessment of the Value, Impact, and Validity of the Jobs and Economic Development Impacts (JEDI) Suite of Models

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    The Jobs and Economic Development Impacts (JEDI) models, developed by the National Renewable Energy Laboratory (NREL) for the U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy (EERE), use input-output methodology to estimate gross (not net) jobs and economic impacts of building and operating selected types of renewable electricity generation and fuel plants. This analysis provides the DOE with an assessment of the value, impact, and validity of the JEDI suite of models. While the models produce estimates of jobs, earnings, and economic output, this analysis focuses only on jobs estimates. This validation report includes an introduction to JEDI models, an analysis of the value and impact of the JEDI models, and an analysis of the validity of job estimates generated by JEDI model through comparison to other modeled estimates and comparison to empirical, observed jobs data as reported or estimated for a commercial project, a state, or a region

    The Business Case for Healthy Grasslands-Based Agriculture – Economic and Social Implications

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    Native perennial warm-season grasses (NWSGs) of the United States (U.S.) provide valuable summer forage. Studies have shown their potential within grazing systems as a complement to cool-season forages, as well as their benefits to soil biota, wildlife biodiversity, carbon sequestration and their resiliency to extreme drought and flood events. In this paper, we demonstrate that, in addition to these benefits, NWSGs provide important economic value to beef and dairy producers as a hedge against financial risks posed by overreliance on cool-season grasses

    Back to the Future: Achieving Resilient, Sustainable Grasslands through Restoration of Ecological Norms / Overview – the Problem, the Opportunity

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    Grasslands are one of the largest biomes on earth, are the largest agricultural enterprise in the U.S., serve as a major carbon pool, produce high quality dietary proteins, and host a rich biodiversity. However, grasslands, including those of the eastern U.S., have been heavily altered and degraded reducing their resiliency and negatively impacting native fauna. Recent scientific advances in grassland establishment and management, along with the opportunity to monetize the carbon benefits of native grasslands, could provide the needed social and economic support to make such restoration possible on a large scale. Where restored grassland communities align with historical, ecological norms of the region, improved resiliency, sustainability, as well as viability of native biota can all be achieved. Such an approach, based on adapted native grasses and focused on the principles of working lands conservation, can be a template for grasslands restoration globally

    Thunderstorm hazards flight research: Storm hazards 1980 overview

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    A highly instrumented NASA F-106B aircraft, modified for the storm hazards mission and protected against direct lightning strikes, was used in conjunction with various ground based radar and lightning measurement systems to collect data during thunderstorm penetration flights. During 69 thunderstorm penetrations, there were 10 direct lightning strikes to the aircraft. No problems were encountered with any of the aircraft's systems as a result of the strikes and the research instrumentation performed as designed. Electromagnetic characteristics of nine strikes were recorded, and the results of other experiments confirm the theory that X-ray radiation and nitrous oxide gas are being produced by processes associated directly with thunderstorm electric fields and lightning discharges. A better understanding of aircraft lightning attachment mechanisms and strike zones is being accomplished by careful inspection, identification, and documentation of lightning attachment points and swept stroke paths following each strike to the aircraft

    SP704-A Potential Impacts on Wildlife of Switchgrass Grown for Biofuels

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    Version 3.

    SP704-A Potential Impacts on Wildlife of Switchgrass Grown for Biofuels

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    Version 3.
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