665 research outputs found
Global and Regional Sea Level Rise Scenarios for the United States
This report and accompanying datasets from the U.S. Sea Level Rise and Coastal Flood Hazard Scenarios and Tools Interagency Task Force provide 1) sea level rise scenarios to 2150 by decade that include estimates of vertical land motion and 2) a set of extreme water level probabilities for various heights along the U.S. coastline. These data are available at 1-degree grids along the U.S. coastline and downscaled specifically at NOAA tide-gauge locations. Estimates of flood exposure are assessed using contemporary U.S. coastal flood-severity thresholds for current conditions (e.g., sea levels and infrastructure footprint) and for the next 30 years (out to year 2050), assuming no additional risk reduction measures are enacted.
This effort builds upon the 2017 Task Force report (Sweet et al., 2017). In particular, the set of global mean sea level rise scenarios from that report are updated and downscaled with output directly from the United Nations Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6; IPCC, 2021a), through the efforts of the NASA Sea Level Change Team; updates include adjustments to the temporal trajectories and exceedance probabilities of these scenarios based upon end-of-century global temperatures. As with the 2017 report, these global mean sea level rise scenarios are regionalized for the U.S. coastline. In addition, methodology supporting the U.S. Department of Defense Regional Sea Level (DRSL) database1 (Hall et al., 2016) is adapted for the extreme water level dataset newly developed for this report.
This report will be a key technical input for the Fifth National Climate Assessment (NCA5). These data and information are being incorporated into current and planned agency tools and services, such as NOAA’s Sea Level Rise Viewer and Inundation Dashboard, NASA’s Sea Level Change Portal, and others. Although the intent of this report is not to provide authoritative guidance or design specifications for a specific project, it is intended to help inform Federal agencies, state and local governments, and stakeholders in coastal communities about current and future sea level rise to help contextualize its effects for decision-making purposes
Characterizing the Preferences and Values of US Recreational Atlantic Bluefin Tuna Anglers
The Atlantic Bluefin Tuna Thunnus thynnus is the target of a recreational fishery along the U.S. East Coast that is thought to be of considerable economic value. In some years, recreational landings have exceeded the sector’s annual subquota due to changes in fish availability, limited predictability of angler effort, and difficulties in realtime monitoring of catch. Understanding the drivers of angler behavior is critical for predicting how effort and harvest may vary as a function of changing fish availability, regulations, or costs. To investigate angler decision making, preferences, and values, we surveyed private recreational anglers from Maine to North Carolina and employed discrete choice experiments to determine how regulatory and nonregulatory trip-specific variables influence trip-taking behavior. A latent class-ranked log it model identified two distinct classes of anglers who exhibited differing preferences in regard to the importance of nonconsumptive aspects of Bluefin Tuna fishing (e.g., catch and release). Income and recent Bluefin Tuna targeting were the primary determinants of class membership, and higher-income anglers who had targeted Bluefin Tuna in the past 5 years were significantly more likely to be in the class that derives substantive benefits from nonconsumptive angling activities. An annual consumer surplus exceeding US$14 million was estimated for the 2015 fishery. We considered potential angler welfare impacts of possible management changes (compensating surplus) and identified a large amount of latent effort currently present in the fishery in the form of consumptive-oriented anglers. As a result, liberalization of harvest regulations could potentially lead to a large influx of effort into the fishery, which could impede the ability of managers to maintain harvest levels within prescribed limits
Modeling effects of tidal and wave mixing on circulation and thermohaline structures in the Bering Sea: Process studies
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95183/1/jgrc11280.pd
Short-Term Pain and Long-Term Gain: Using Phased-In Minimum Size Limits to Rebuild Stocks-the Pacific Bluefin Tuna Example
Like many stocks, the Pacific Bluefin Tuna Thunnus orientalis has been considerably depleted. High exploitation rates on very young fish have reduced the spawning stock biomass (SSB) to 2.6% of the unexploited level. We provide a framework for exploring potential benefits of minimum size regulations as a mechanism for rebuilding stocks, and we illustrate the approach using simulations patterned after Pacific Bluefin Tuna dynamics. We attempt to mitigate short-term losses in yield by considering a phased-in management strategy. With this approach, the minimum size limit (MSL) is gradually increased as biomass rebuilds, giving fishing communities time to adjust to new restrictions. We estimated short- and long-term effects of different MSLs on yield and biomass by using data from the 2016 assessment. A variety of scenarios was considered for growth compensation, discard mortality, and interest rates. The long-term value of the fishery was maximized by setting an MSL of 92 cm FL, which resulted in a 70% loss in yield during the first year (short-term pain). By implementing the MSL in two phases (64 cm FL in year 1; 92 cm FL in subsequent years), the long-term value of the fishery was maintained, and the short-term pain was reduced to a maximum 46% loss in yield during any 1 year. Under a three-phase implementation (55 cm FL in year 1; 77 cm FL in year 2; and 92 cm FL in subsequent years), the short-term pain was further reduced to a maximum loss of 30% during any 1 year. With no discard mortality, long-term yield increased by 165% and SSB increased 13-fold (to 33% of virgin SSB), regardless of the number of phases used. Long-term benefits were quickly diminished with increasing discard mortality. This simulation approach is widely applicable to cases where minimum size changes are contemplated; for Pacific Bluefin Tuna, our simulations demonstrate that size limits should be considered
Evaluating the use of marine protected areas by endangered species: A habitat selection approach
1. Optimizing the design of marine protected area (MPA) networks for the conservation of migratory marine species and their habitats involves a suite of important considerations, such as appropriate scale requirements and the distribution of anthropogenic impacts. Often, a fundamental component of the conservation planning process is delineating areas of high use or high biodiversity within a region of interest.
2. However, basing conservation strategies off merely the number of individuals in an ecosystem is outdated and potentially subject to arbitrary thresholds. To be effective at protecting marine megafauna, MPAs would ideally encompass habitats used by focal species. Through satellite-tracking studies, evidence of whether species actually use protected areas is emerging.
3. Here, we present a multispecies perspective on habitat selection within existing MPAs throughout the Floridian ecoregion, which encompasses coastal Florida and the Gulf of Mexico. Using an 11-year satellite-tracking dataset on 235 marine turtles, we used integrated step selection analysis to quantify the effects of sea turtle behavioural state (identified by a switching state-space model), protected area status, chlorophyll and bathymetry on habitat selection.
4. Our results show that sea turtles do select for existing protected areas, specifically multi-use zones, while controlling for the effects of depth and primary productivity. However, our analysis revealed that turtles showed no selection for the no-take zones within MPAs, during either transiting or foraging.
5. These findings contribute to the existing literature base of MPA use for highly mobile, imperilled species and could inform management of existing MPAs or changes to zoning, specifically multi-use to no-take. Our use of a robust spatial modelling framework to evaluate habitat selection relative to MPAs could be incorporated into conservation planning to build MPA networks designed to accommodate migratory species
Using ecosystem-services assessments to determine trade-offs in ecosystem-based management of marine mammals
The goal of ecosystem-based management (EBM) is to support a sustainable and holistic
multisectored management approach, and is recognized in a number of international policy
frameworks. However, it remains unknown how these goals should be linked to assessments and
management plans for marine fauna, such as mammals and fish stocks. It appears particularly
challenging to carry out trade-off analyses of various ocean uses without a framework that
integrates knowledge of environmental, social, and economic benefits derived from nonstationary
marine fauna. We argue this gap can be filled by applying a version of the ecosystem-service
approach at the population level of marine fauna. To advance this idea, we used marine mammals as
a case study to demonstrate what indicators could operationalize relevant assessments and deliver
an evidence base for the presence of ecosystem services and disservices derived from marine
mammals. We found indicators covering common ecosystem service categories feasible to apply;
examples of indicator data are already available in the literature for several populations. We
encourage further exploration of this approach for application to marina fauna and biodiversity
management, with the caveat that conceptual tensions related to the use of the ecosystem service
concept itself needs to be addressed to ensure acceptance by relevant stakeholders
Impact of large-scale climatic oscillations on snowfall-related climate parameters in the world's major downhill ski areas: a review
Skiers are passionate about finding the best snow conditions. Snow conditions in thousands of ski resorts around the world depend mainly on natural snowfall, particularly in the case of backcountry skiing. In various mountain ranges popular among skiers, snowfall is strongly linked to large-scale climatic oscillations. This paper reviews existing information on the impacts of several of these phenomena, such as the El Niño-Southern Oscillation, North Atlantic Oscillation, and North Pacific Index, on snowfall-related climate parameters in the world's major ski areas. We found that in each of the studied areas, one or more large-scale climatic oscillations affected snowfall-related climate parameters. Understanding the predictability of such oscillations is high on the climate research agenda. If this research leads to improved predictability in the coming years, this could be combined with the knowledge summarized in our paper on the relationships between climatic oscillations and snow-related parameters to provide useful information for winter sports and other snow-related fields. © 2012 International Mountain Society
The Indian Ocean Dipole and Cholera Incidence in Bangladesh: A Time-Series Analysis
Background: It has been reported that the El Niño–Southern Oscillation (ENSO) influences the interannual variation of endemic cholera in Bangladesh. There is increased interest in the influence of the Indian Ocean dipole (IOD), a climate mode of coupled ocean–atmosphere variability, on regional ocean climate in the Bay of Bengal and on Indian monsoon rainfall. Objectives: We explored the relationship between the IOD and the number of cholera patients in Bangladesh, controlling for the effects of ENSO. Me t h o d s: Time-series regression was performed. Negative binomial models were used to estimate associations between the monthly number of hospital visits for cholera in Dhaka and Matlab (1993–2007) and the dipole mode index (DMI) controlling for ENSO index [NINO3, a measure of the average sea surface temperature (SST) in the Niño 3 region], seasonal, and interannual variations. Associations between cholera cases and SST and sea surface height (SSH) of the northern Bay of Bengal were also examined. Re s u l t s: A 0.1-unit increase in average DMI during the current month through 3 months before was associated with an increase in cholera incidence of 2.6 % [(95 % confidence interval (CI), 0.0–5.2; p = 0.05] in Dhaka and 6.9 % (95 % CI, 3.2–10.8; p < 0.01) in Matlab. Cholera incidence in Dhaka increased by 2.4 % (95 % CI, 0.0–5.0; p = 0.06) after a 0.1‑unit decrease in DMI 4–7 months before. Hospital visits for cholera in both areas were positively associated with SST 0–3 months before, after adjusting for SSH (p < 0.01). Con c l u s i o n s: These findings suggest that both negative and positive dipole events are associated with an increased incidence of cholera in Bangladesh with varying time lags. Key w o r d s: Bangladesh, cholera, El Niño–Southern Oscillation, Indian Ocean dipole, timeseries analysis. Environ Health Perspect 119:239–244 (2011). doi:10.1289/ehp.1002302 [Onlin
Patterns in Greater Sage-grouse population dynamics correspond with public grazing records at broad scales
Human land use, such as livestock grazing, can have profound yet varied effects on wildlife interacting within common ecosystems, yet our understanding of land-use effects is often generalized from short-term, local studies that may not correspond with trends at broader scales. Here we used public land records to characterize livestock grazing across Wyoming, USA, and we used Greater Sage-grouse (Centrocercus urophasianus) as a model organism to evaluate responses to livestock management. With annual counts of male Sage-grouse from 743 leks (breeding display sites) during 2004-2014, we modeled population trends in response to grazing level (represented by a relative grazing index) and timing across a gradient in vegetation productivity as measured by the Normalized Vegetation Difference Index (NDVI). We found grazing can have both positive and negative effects on Sage-grouse populations depending on the timing and level of grazing. Sage-grouse populations responded positively to higher grazing levels after peak vegetation productivity, but populations declined when similar grazing levels occurred earlier, likely reflecting the sensitivity of cool-season grasses to grazing during peak growth periods. We also found support for the hypothesis that effects of grazing management vary with local vegetation productivity. These results illustrate the importance of broad-scale analyses by revealing patterns in Sage-grouse population trends that may not be inferred from studies at finer scales, and could inform sustainable grazing management in these ecosystems
Strength and ductility demands on wind turbine towers due to earthquake and wind load
In earthquake prone areas, wind and earthquake loads are assumed to be statistically uncorrelated, therefore their interaction is ignored by existing design guidelines. However, the fact that strong earthquake events are commonly followed by aftershocks and that wind is constantly flowing at high speeds around wind farms increase the probability of their joint occurrence, thus making current design assumptions questionable. This investigation shows that multi-hazard scenarios magnify strength demands of wind turbine towers designed against isolated load conditions, hence modifying their performance level. It is also shown that, under certain conditions, the probabilities associated to the joint occurrence of earthquake and low to strong wind events match or exceed those related to the original design, thus rendering wind energy infrastructure susceptible to unforeseen damage
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