992 resultados para tropical storms
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Caribbean policymakers are faced with special challenges from climate change and these are related to the uncertainties inherent in future climate projections and the complex linkages among climate change, physical and biological systems and socioeconomic sectors. The impacts of climate change threaten development in the Caribbean and may well erode previous gains in development as evidenced by the increased incidence of climate migrants internationally. This brief which is based on a recent study conducted by the Economic Commission for Latin America and the Caribbean (LC/CAR/L.395)1 provides a synthesis of the assessment of the economic and social impacts of climate change on the coastal and marine sector in the Caribbean which were undertaken. It provides Caribbean policymakers with cutting-edge information on the region’s vulnerability and encourages the development of adaptation strategies informed by both local experience and expert knowledge. It proceeds from an acknowledgement that the unique combination of natural resources, ecosystems, economic activities, and human population settlements of the Caribbean will not be immune to the impacts of climate change, and local communities, countries and the subregion as a whole need to plan for, and adapt to, these effects. Climate and extreme weather hazards related to the coastal and marine sector encompass the distinct but related factors of sea level rise, increasing coastal water temperatures, tropical storms and hurricanes. Potential vulnerabilities for coastal zones include increased shoreline erosion leading to alteration of the coastline, loss of coastal wetlands, and changes in the abundance and diversity of fish and other marine populations. The study examines four key themes in the analysis: climate, vulnerability, economic and social costs associated with climate change impacts, and adaptive measures.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Large parts of the world are subjected to one or more natural hazards, such as earthquakes, tsunamis, landslides, tropical storms (hurricanes, cyclones and typhoons), costal inundation and flooding. Virtually the entire world is at risk of man-made hazards. In recent decades, rapid population growth and economic development in hazard-prone areas have greatly increased the potential of multiple hazards to cause damage and destruction of buildings, bridges, power plants, and other infrastructure; thus posing a grave danger to the community and disruption of economic and societal activities. Although an individual hazard is significant in many parts of the United States (U.S.), in certain areas more than one hazard may pose a threat to the constructed environment. In such areas, structural design and construction practices should address multiple hazards in an integrated manner to achieve structural performance that is consistent with owner expectations and general societal objectives. The growing interest and importance of multiple-hazard engineering has been recognized recently. This has spurred the evolution of multiple-hazard risk-assessment frameworks and development of design approaches which have paved way for future research towards sustainable construction of new and improved structures and retrofitting of the existing structures. This report provides a review of literature and the current state of practice for assessment, design and mitigation of the impact of multiple hazards on structural infrastructure. It also presents an overview of future research needs related to multiple-hazard performance of constructed facilities.
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Haiti, conocida en la época colonial como 'la Perla de las Antillas', su economía se organizó entorno a la producción de azúcar que proveían a través de Francia al resto de Europa. De este modo 70de la producción de azúcar era consumido en Europa y más del 60del café. Con una lógica que perseguía obtener los máximos rindes, buscaron mano de obra esclava en el África Subsahariana, población que directamente reemplazó a la originaria. Así comienza a plantearse el desarrollo de un tipo de economía en Haiti, que traería graves consecuencias ambientales hasta la actualidad. Hoy es el país más pobre de América, con una esperanza de vida de alrededor de 60 años, y la tasa de analfabetismo del 52. Ubicado en un área tropical, es frecuente que sufra el impacto de las tormentas tropicales y ciclones que, como consecuencia de una tala desmedida de laforestación originaria, las inundaciones acentúan los problemas, a lo que se suman los problemas sanitarios inherentes a un nivel de vida con tantas carencias; y a la preponderancia de minifundios en el área rural, llevan a conformar un escenario de enorme vulnerabilidad. En el año 2010, una triste noticia pondría a Haïti en el centro de la escena mundial: el terremoto de marzo de ese año que afectara el área de Puerto Príncipe dejando alrededor de 300.000 muertos y más de un millón de damnificados. En la actualidad la presencia debarrios enteros viviendo en carpas en espacios públicos, son una expresión de la vigencia de dicho evento. Sin embargo, desde mediados de la década pasada tienen lugar proyectos que intentan territorializar una experiencia argentina de reconocido impacto en procura de atender las necesidades de la población con mayor vulnerabilidad que habita en los espacios rurales. Se trata del Programa Pro Huerta, que desde hace más de veinte años se desarrolla en Argentina y se propuso en el ámbito de este país desde la perspectiva de la cooperación internacional. De este modo, en distintos departamentos de Haiti con el trabajo en conjunto de diversos países ponen en marcha un proyecto social de seguridad alimentaria. La finalidad es el análisis de la territorialización de la experiencia Pro Huerta Haiti a partir del enfoque de cooperación internacional del cual Argentina participa junto con Canadá y Haiti. Entre los resultados y aportes de esta investigación, se pudo constatar que en Haïtí se fortalecen las redes sociales, la familia, el trabajo solidario, la salud y en conjunto contribuyen a fortalecer la soberanía alimentaria, en un país con grandes carencias y gran vulnerabilidad. Asimismo, es interesante resaltar que el modelo de Cooperación Sur-Sur que la Argentina desarrolla, desde una visión horizontal donde nuestro país camina junto a Haití y Canadá en el aprendizaje cotidiano del crecimiento conjunto, donde cada país tiene mucho por seguir aprendiendo
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Haiti, conocida en la época colonial como 'la Perla de las Antillas', su economía se organizó entorno a la producción de azúcar que proveían a través de Francia al resto de Europa. De este modo 70de la producción de azúcar era consumido en Europa y más del 60del café. Con una lógica que perseguía obtener los máximos rindes, buscaron mano de obra esclava en el África Subsahariana, población que directamente reemplazó a la originaria. Así comienza a plantearse el desarrollo de un tipo de economía en Haiti, que traería graves consecuencias ambientales hasta la actualidad. Hoy es el país más pobre de América, con una esperanza de vida de alrededor de 60 años, y la tasa de analfabetismo del 52. Ubicado en un área tropical, es frecuente que sufra el impacto de las tormentas tropicales y ciclones que, como consecuencia de una tala desmedida de laforestación originaria, las inundaciones acentúan los problemas, a lo que se suman los problemas sanitarios inherentes a un nivel de vida con tantas carencias; y a la preponderancia de minifundios en el área rural, llevan a conformar un escenario de enorme vulnerabilidad. En el año 2010, una triste noticia pondría a Haïti en el centro de la escena mundial: el terremoto de marzo de ese año que afectara el área de Puerto Príncipe dejando alrededor de 300.000 muertos y más de un millón de damnificados. En la actualidad la presencia debarrios enteros viviendo en carpas en espacios públicos, son una expresión de la vigencia de dicho evento. Sin embargo, desde mediados de la década pasada tienen lugar proyectos que intentan territorializar una experiencia argentina de reconocido impacto en procura de atender las necesidades de la población con mayor vulnerabilidad que habita en los espacios rurales. Se trata del Programa Pro Huerta, que desde hace más de veinte años se desarrolla en Argentina y se propuso en el ámbito de este país desde la perspectiva de la cooperación internacional. De este modo, en distintos departamentos de Haiti con el trabajo en conjunto de diversos países ponen en marcha un proyecto social de seguridad alimentaria. La finalidad es el análisis de la territorialización de la experiencia Pro Huerta Haiti a partir del enfoque de cooperación internacional del cual Argentina participa junto con Canadá y Haiti. Entre los resultados y aportes de esta investigación, se pudo constatar que en Haïtí se fortalecen las redes sociales, la familia, el trabajo solidario, la salud y en conjunto contribuyen a fortalecer la soberanía alimentaria, en un país con grandes carencias y gran vulnerabilidad. Asimismo, es interesante resaltar que el modelo de Cooperación Sur-Sur que la Argentina desarrolla, desde una visión horizontal donde nuestro país camina junto a Haití y Canadá en el aprendizaje cotidiano del crecimiento conjunto, donde cada país tiene mucho por seguir aprendiendo
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Haiti, conocida en la época colonial como 'la Perla de las Antillas', su economía se organizó entorno a la producción de azúcar que proveían a través de Francia al resto de Europa. De este modo 70de la producción de azúcar era consumido en Europa y más del 60del café. Con una lógica que perseguía obtener los máximos rindes, buscaron mano de obra esclava en el África Subsahariana, población que directamente reemplazó a la originaria. Así comienza a plantearse el desarrollo de un tipo de economía en Haiti, que traería graves consecuencias ambientales hasta la actualidad. Hoy es el país más pobre de América, con una esperanza de vida de alrededor de 60 años, y la tasa de analfabetismo del 52. Ubicado en un área tropical, es frecuente que sufra el impacto de las tormentas tropicales y ciclones que, como consecuencia de una tala desmedida de laforestación originaria, las inundaciones acentúan los problemas, a lo que se suman los problemas sanitarios inherentes a un nivel de vida con tantas carencias; y a la preponderancia de minifundios en el área rural, llevan a conformar un escenario de enorme vulnerabilidad. En el año 2010, una triste noticia pondría a Haïti en el centro de la escena mundial: el terremoto de marzo de ese año que afectara el área de Puerto Príncipe dejando alrededor de 300.000 muertos y más de un millón de damnificados. En la actualidad la presencia debarrios enteros viviendo en carpas en espacios públicos, son una expresión de la vigencia de dicho evento. Sin embargo, desde mediados de la década pasada tienen lugar proyectos que intentan territorializar una experiencia argentina de reconocido impacto en procura de atender las necesidades de la población con mayor vulnerabilidad que habita en los espacios rurales. Se trata del Programa Pro Huerta, que desde hace más de veinte años se desarrolla en Argentina y se propuso en el ámbito de este país desde la perspectiva de la cooperación internacional. De este modo, en distintos departamentos de Haiti con el trabajo en conjunto de diversos países ponen en marcha un proyecto social de seguridad alimentaria. La finalidad es el análisis de la territorialización de la experiencia Pro Huerta Haiti a partir del enfoque de cooperación internacional del cual Argentina participa junto con Canadá y Haiti. Entre los resultados y aportes de esta investigación, se pudo constatar que en Haïtí se fortalecen las redes sociales, la familia, el trabajo solidario, la salud y en conjunto contribuyen a fortalecer la soberanía alimentaria, en un país con grandes carencias y gran vulnerabilidad. Asimismo, es interesante resaltar que el modelo de Cooperación Sur-Sur que la Argentina desarrolla, desde una visión horizontal donde nuestro país camina junto a Haití y Canadá en el aprendizaje cotidiano del crecimiento conjunto, donde cada país tiene mucho por seguir aprendiendo
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Precipitation data collected from five sites in south Florida indicate a strong seasonal and spatial variation in δ18O and δD, despite the relatively limited geographic coverage and low-lying elevation of each of the collection sites. Based upon the weighted-mean stable isotope values, the sites were classified as coastal Atlantic, inland, and lower Florida Keys. The coastal Atlantic sites had weighted-mean values of δ18O and δD of −2.86‰ and −12.8‰, respectively, and exhibited a seasonal variation with lower δ18O and δD values in the summer wet-season precipitation (δ18O = −3.38‰, δD = −16.5‰) as compared to the winter-time precipitation (δ18O = −1.66‰, δD = −3.2‰). The inland site was characterized as having the highest d-excess value (+13.3‰), signifying a contribution of evaporated Everglades surface water to the local atmospheric moisture. In spite of its lower latitude, the lower Keys site located at Long Key had the lowest weighted-mean stable isotope values (δ18O = −3.64‰, δD = −20.2‰) as well as the lowest d-excess value of (+8.8‰). The lower δD and δ18O values observed at the Long Key site reflect the combined effects of oceanic vapor source, fractionation due to local precipitation, and slower equilibration of the larger raindrops nucleated by a maritime aerosol. Very low δ18O and δD values (δ18O < −6‰, δD < −40‰) were observed just prior to the passage of hurricanes from the Gulf of Mexico as well as during cold fronts from the north-west. These results suggest that an oceanic vapor source region to the west, may be responsible for the extremely low δD and δ18O values observed during some tropical storms and cold fronts.
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The goal of this investigation was to examine how sediment accretion and organic carbon (OC) burial rates in mangrove forests respond to climate change. Specifically, will the accretion rates keep pace with sea-level rise, and what is the source and fate of OC in the system? Mass accumulation, accretion and OC burial rates were determined via 210Pb dating (i.e. 100 year time scale) on sediment cores collected from two mangrove forest sites within Everglades National Park, Florida (USA). Enhanced mass accumulation, accretion and OC burial rates were found in an upper layer that corresponded to a well-documented storm surge deposit. Accretion rates were 5.9 and 6.5 mm yr− 1 within the storm deposit compared to overall rates of 2.5 and 3.6 mm yr− 1. These rates were found to be matching or exceeding average sea-level rise reported for Key West, Florida. Organic carbon burial rates were 260 and 393 g m− 2 yr− 1 within the storm deposit compared to 151 and 168 g m− 2 yr− 1 overall burial rates. The overall rates are similar to global estimates for OC burial in marine wetlands. With tropical storms being a frequent occurrence in this region the resulting storm surge deposits are an important mechanism for maintaining both overall accretion and OC burial rates. Enhanced OC burial rates within the storm deposit could be due to an increase in productivity created from higher concentrations of phosphorus within storm-delivered sediments and/or from the deposition of allochthonous OC. Climate change-amplified storms and sea-level rise could damage mangrove forests, exposing previously buried OC to oxidation and contribute to increasing atmospheric CO2 concentrations. However, the processes described here provide a mechanism whereby oxidation of OC would be limited and the overall OC reservoir maintained within the mangrove forest sediments.
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In fire-dependent forests, managers are interested in predicting the consequences of prescribed burning on postfire tree mortality. We examined the effects of prescribed fire on tree mortality in Florida Keys pine forests, using a factorial design with understory type, season, and year of burn as factors. We also used logistic regression to model the effects of burn season, fire severity, and tree dimensions on individual tree mortality. Despite limited statistical power due to problems in carrying out the full suite of planned experimental burns, associations with tree and fire variables were observed. Post-fire pine tree mortality was negatively correlated with tree size and positively correlated with char height and percent crown scorch. Unlike post-fire mortality, tree mortality associated with storm surge from Hurricane Wilma was greater in the large size classes. Due to their influence on population structure and fuel dynamics, the size-selective mortality patterns following fire and storm surge have practical importance for using fire as a management tool in Florida Keys pinelands in the future, particularly when the threats to their continued existence from tropical storms and sea level rise are expected to increase.
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Mangrove forests are ecosystems susceptible to changing water levels and temperatures due to climate change as well as perturbations resulting from tropical storms. Numerical models can be used to project mangrove forest responses to regional and global environmental changes, and the reliability of these models depends on surface energy balance closure. However, for tidal ecosystems, the surface energy balance is complex because the energy transport associated with tidal activity remains poorly understood. This study aimed to quantify impacts of tidal flows on energy dynamics within a mangrove ecosystem. To address the research objective, an intensive 10-day study was conducted in a mangrove forest located along the Shark River in the Everglades National Park, FL, USA. Forest–atmosphere turbulent exchanges of energy were quantified with an eddy covariance system installed on a 30-m-tall flux tower. Energy transport associated with tidal activity was calculated based on a coupled mass and energy balance approach. The mass balance included tidal flows and accumulation of water on the forest floor. The energy balance included temporal changes in enthalpy, resulting from tidal flows and temperature changes in the water column. By serving as a net sink or a source of available energy, flood waters reduced the impact of high radiational loads on the mangrove forest. Also, the regression slope of available energy versus sink terms increased from 0.730 to 0.754 and from 0.798 to 0.857, including total enthalpy change in the water column in the surface energy balance for 30-min periods and daily daytime sums, respectively. Results indicated that tidal inundation provides an important mechanism for heat removal and that tidal exchange should be considered in surface energy budgets of coastal ecosystems. Results also demonstrated the importance of including tidal energy advection in mangrove biophysical models that are used for predicting ecosystem response to changing climate and regional freshwater management practices.
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The goal of this investigation was to examine how sediment accretion and organic carbon (OC) burial rates in mangrove forests respond to climate change. Specifically, will the accretion rates keep pace with sea-level rise, and what is the source and fate of OC in the system? Mass accumulation, accretion and OC burial rates were determined via 210Pb dating (i.e. 100 year time scale) on sediment cores collected from two mangrove forest sites within Everglades National Park, Florida (USA). Enhanced mass accumulation, accretion and OC burial rates were found in an upper layer that corresponded to a well-documented storm surge deposit. Accretion rates were 5.9 and 6.5 mm yr− 1 within the storm deposit compared to overall rates of 2.5 and 3.6 mm yr− 1. These rates were found to be matching or exceeding average sea-level rise reported for Key West, Florida. Organic carbon burial rates were 260 and 393 g m− 2 yr− 1 within the storm deposit compared to 151 and 168 g m− 2 yr− 1 overall burial rates. The overall rates are similar to global estimates for OC burial in marine wetlands. With tropical storms being a frequent occurrence in this region the resulting storm surge deposits are an important mechanism for maintaining both overall accretion and OC burial rates. Enhanced OC burial rates within the storm deposit could be due to an increase in productivity created from higher concentrations of phosphorus within storm-delivered sediments and/or from the deposition of allochthonous OC. Climate change-amplified storms and sea-level rise could damage mangrove forests, exposing previously buried OC to oxidation and contribute to increasing atmospheric CO2 concentrations. However, the processes described here provide a mechanism whereby oxidation of OC would be limited and the overall OC reservoir maintained within the mangrove forest sediments.
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This study documents the 1996 and 1997 autumn migration seasons at Grassy Key for 16 species of raptors (hawks, eagles, and falcons). My results indicate the Florida Keys are a major raptor migration flyway (over 26,000 sightings). I identified factors influencing watch-site location in the Keys. Northbound flights must be included to avoid inflating southbound counts. By removing the "season effect" (natural rise, peak, and wane of raptor numbers during migration), I demonstrate wind has little consistent effect on raptor counts in the Keys. I further demonstrate we do not see more raptors on cold front days than on non-cold front days. However, cold fronts following tropical storms (as in 1996) increase the number of raptors observed for most species. I conducted a nightly roosting survey on Boot Key resulting in near or over 3,000 raptor sightings per season and present a model to predict aerial counts from roosting counts.
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Periods of drought and low streamflow can have profound impacts on both human and natural systems. People depend on a reliable source of water for numerous reasons including potable water supply and to produce economic value through agriculture or energy production. Aquatic ecosystems depend on water in addition to the economic benefits they provide to society through ecosystem services. Given that periods of low streamflow may become more extreme and frequent in the future, it is important to study the factors that control water availability during these times. In the absence of precipitation the slower hydrological response of groundwater systems will play an amplified role in water supply. Understanding the variability of the fraction of streamflow contribution from baseflow or groundwater during periods of drought provides insight into what future water availability may look like and how it can best be managed. The Mills River Basin in North Carolina is chosen as a case-study to test this understanding. First, obtaining a physically meaningful estimation of baseflow from USGS streamflow data via computerized hydrograph analysis techniques is carried out. Then applying a method of time series analysis including wavelet analysis can highlight signals of non-stationarity and evaluate the changes in variance required to better understand the natural variability of baseflow and low flows. In addition to natural variability, human influence must be taken into account in order to accurately assess how the combined system reacts to periods of low flow. Defining a combined demand that consists of both natural and human demand allows us to be more rigorous in assessing the level of sustainable use of a shared resource, in this case water. The analysis of baseflow variability can differ based on regional location and local hydrogeology, but it was found that baseflow varies from multiyear scales such as those associated with ENSO (3.5, 7 years) up to multi decadal time scales, but with most of the contributing variance coming from decadal or multiyear scales. It was also found that the behavior of baseflow and subsequently water availability depends a great deal on overall precipitation, the tracks of hurricanes or tropical storms and associated climate indices, as well as physiography and hydrogeology. Evaluating and utilizing the Duke Combined Hydrology Model (DCHM), reasonably accurate estimates of streamflow during periods of low flow were obtained in part due to the model’s ability to capture subsurface processes. Being able to accurately simulate streamflow levels and subsurface interactions during periods of drought can be very valuable to water suppliers, decision makers, and ultimately impact citizens. Knowledge of future droughts and periods of low flow in addition to tracking customer demand will allow for better management practices on the part of water suppliers such as knowing when they should withdraw more water during a surplus so that the level of stress on the system is minimized when there is not ample water supply.
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HURDAT is the main historical archive of all tropical storms and hurricanes in the North Atlantic Basin, which includes the Caribbean Sea and Gulf of Mexico, from 1851 to the present. HURDAT is maintained and updated annually by the National Hurricane Center at Miami, Florida. Today, HURDAT is widely used by research scientists, operational hurricane forecasters, insurance companies, emergency managers and others. HURDAT contains both systematic biases and random errors. Thus, the reanalysis of HURDAT is vital. For this thesis, HURDAT is reanalyzed for the period of 1954-1963. The track and intensity of each existing tropical cyclone in HURDAT is assessed in the light of 21st century understanding and previously unrecognized tropical cyclones are detected and analyzed. The resulting changes will be recommended to the National Hurricane Center Best Track Change Committee for inclusion in HURDAT.
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Geologic hazards affect the lives of millions of people worldwide every year. El Salvador is a country that is regularly affected by natural disasters, including earthquakes, volcanic eruptions and tropical storms. Additionally, rainfall-induced landslides and debris flows are a major threat to the livelihood of thousands. The San Vicente Volcano in central El Salvador has a recurring and destructive pattern of landslides and debris flows occurring on the northern slopes of the volcano. In recent memory there have been at least seven major destructive debris flows on San Vicente volcano. Despite this problem, there has been no known attempt to study the inherent stability of these volcanic slopes and to determine the thresholds of rainfall that might lead to slope instability. This thesis explores this issue and outlines a suggested method for predicting the likelihood of slope instability during intense rainfall events. The material properties obtained from a field campaign and laboratory testing were used for a 2-D slope stability analysis on a recent landslide on San Vicente volcano. This analysis confirmed that the surface materials of the volcano are highly permeable and have very low shear strength and provided insight into the groundwater table behavior during a rainstorm. The biggest factors on the stability of the slopes were found to be slope geometry, rainfall totals and initial groundwater table location. Using the results from this analysis a stability chart was created that took into account these main factors and provided an estimate of the stability of a slope in various rainfall scenarios. This chart could be used by local authorities in the event of a known extreme rainfall event to help make decisions regarding possible evacuation. Recommendations are given to improve the methodology for future application in other areas as well as in central El Salvador.