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61.
Analysis of the coastal Mississippi storm surge hazard 总被引：6，自引：0，他引：6
Following the extreme flooding caused by Hurricane Katrina, the Federal Emergency Management Agency (FEMA) commissioned a study to update the Mississippi coastal flood hazard maps. The project included development and application of new methods incorporating the most recent advances in numerical modeling of storms and coastal hydrodynamics, analysis of the storm climatology, and flood hazard evaluation. This paper discusses the methods that were used and how they were applied to the coast of the State of Mississippi. 相似文献
62.
Ziming Ke Alexander E. Yankovsky 《Continental Shelf Research》2011,31(9):929-938
A set of numerical experiments has been performed in order to analyze the long-wave response of the coastal ocean to a translating mesoscale atmospheric cyclone approaching the coastline at a normal angle. An idealized two-slope shelf topography is chosen. The model is forced by a radially symmetric atmospheric pressure perturbation with a corresponding gradient wind field. The cyclone's translation speed, radius, and the continental shelf width are considered as parameters whose impact on the long wave period, modal structure, and amplitude is studied. Subinertial continental shelf waves (CSW) dominate the response under typical forcing conditions and on the narrower shelves. They propagate in the downstream (in the sense of Kelvin wave propagation) direction. Superinertial edge wave modes have higher free surface amplitudes and faster phase speeds than the CSW modes. While potentially more dangerous, edge waves are not as common as subinertial shelf waves because their generation requires a wide, gently sloping shelf and a storm system translating at a relatively high (∼10 m s−1 or faster) speed. A relatively smaller size of an atmospheric cyclone also favors edge wave generation. Edge waves with the highest amplitude (up to 60% of the forced storm surge) propagate upstream. They are produced by a storm system with an Eulerian time scale equal to the period of a zero-mode edge wave with the wavelength of the storm spatial scale. Large amplitude edge waves were generated during Hurricane Wilma's landfall (2005) on the West Florida shelf with particularly severe flooding occurring upstream of the landfall site. 相似文献
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64.
An approach to utilizing adaptive mesh refinement algorithms for storm surge modeling is proposed. Currently numerical models exist that can resolve the details of coastal regions but are often too costly to be run in an ensemble forecasting framework without significant computing resources. The application of adaptive mesh refinement algorithms substantially lowers the computational cost of a storm surge model run while retaining much of the desired coastal resolution. The approach presented is implemented in the GeoClaw framework and compared to ADCIRC for Hurricane Ike along with observed tide gauge data and the computational cost of each model run. 相似文献
65.
Ervin G. Otvos 《Quaternary Research》2005,63(3):1001-373
A bottomland flora that prevailed between 9900 and 6000 cal yr B.P. in a North Carolina stream valley may not reflect a regionally much wetter Atlantic climate, coeval with record drought in the Great Plains region and assumed dry Gulf coastal conditions. Such conditions were inferred for 6000 ± 1000 yr ago when the Bermuda High may have consistently occupied summer positions far to the NE. Arid episodes coeval with the Little River local wet interval are known from eolian sediments and pollen spectra in the Atlantic and the Gulf coastal plain. For multiple reasons, the regional extent, intensity, and duration of coastal aridity and alternating wet phases and the Bermuda High positions are not yet adequately constrained. The climate and edaphic causes for the steadily growing predominance of southern pines over hardwoods, achieved between 8900 and 4200 cal yr B.P. at different sites at different times are similarly still unresolved. New data from Shelby Lake, AL, reconfirms that no credible field or other proxy evidence exists for a previously postulated “catastrophic Gulf hurricane phase” in the late Holocene. 相似文献
66.
The present state-of-the-art for natech risk and management is discussed. Examples of recent natechs include catastrophic
oil spills associated with Hurricane Katrina and hazardous chemical releases in Europe during the heavy floods of 2002. Natechs
create difficult challenges for emergency responders due to the geographical extent of the natural disaster, the likelihood
of simultaneous releases, emergency personnel being preoccupied with response to the natural disaster, mitigation measures
failing due to the effects of the natural disaster, and others. Recovery from natechs may be much more difficult than for
“normal” chemical accidents, as the economic and social conditions of the industrial facility and the surrounding community
may have been drastically altered by the natural disaster. Potential safeguards against natechs include adoption of stricter
design criteria, chemical process safeguards, community land use planning, disaster mitigation and response planning, and
sustainable industrial processes, but these safeguards are only sporadically applied. Ultimately, the public must engage in
a comprehensive discussion of acceptable risks for natechs.
相似文献
| Ana Maria CruzEmail: |
67.
R. A. Davis Jr. 《Environmental Geology》1995,25(3):143-148
Hurricane Andrew, one of the strongest storms of the century, crossed the southern part of the Florida peninsula on 24 August 1992. Its path crossed the Florida Everglades and exited in the national park across a mangrove-dominated coast onto the shallow, low-energy, inner shelf. The storm caused extensive breakage and defoliation in the mangrove community; full recovery will take decades. It produced no extensive sedimentation unit; only local and ephemeral ebb-surge deposits. The discontinuous shelly storm beach ridge was breached at multiple locations, and it moved landward a few meters. After seven months, there was little geologic indication that the storm had passed. It is likely that the stratigraphic record in this area will not contain any recognizable features of the passage of Hurricane Andrew. 相似文献
68.
Yi Qiang Nina S.-N. Lam 《International journal of geographical information science》2016,30(9):1832-1852
ABSTRACTUnderstanding human dynamics after a major disaster is important to the region’s sustainable development. This study utilized land cover data to examine how Hurricane Katrina has affected the urban growth pattern in the Mississippi Delta in Louisiana. The study analyzed land cover changes from non-urban to urban in three metropolitan areas, Baton Rouge, New Orleans-Metairie, and Hammond, for two time periods, pre-Katrina (2001–2006) and post-Katrina (2006–2010). The study first applied a focal filter to extract continuous urban areas from the scattered urban pixels in the original remote sensing images. Statistical analyses were applied to develop initial functions between urban growth probability and several driving factors. A genetic algorithm was then used to calibrate the transition function, and cellular automata simulation based on the transition function was conducted to evaluate future urban growth patterns with and without the impact of Hurricane Katrina. The results show that elevation has become a much more important factor after Hurricane Katrina, and urban growth has shifted to higher elevation regions. The elevation most probable for new urban growth increased from 10.84 to 11.90 meters. Moreover, simulated future urban growth in this region indicates a decentralized trend, with more growth occurring in more distant regions with higher elevation. In the New Orleans metropolitan area, urban growth will continue to spill across Lake Pontchartrain to the satellite towns that are more than 50 minutes away by driving from the city center. 相似文献
69.
The role that family and household structure, size, and ethnic/racial composition play in increasing or decreasing vulnerability to natural hazards, which has been missing from the literature, is investigated. The study first reviews the conceptual foundations of the relationships between families/households and natural hazards vulnerability and then employs a principal components analysis to uncover spatial variations in the vulnerability of families and households to hurricane storm surge hazards in Sarasota County, Florida. The analysis identifies and maps five principal components that explain approximately 83% of the variance in family/household population: nuclear families/households; Black families/households; nonfamily, young adult group households; Hispanic families/households; and Asian families/households. Comparison of storm surge risk maps with the locations of these families/households shows the relative vulnerability of each of these family/household categories, with elderly householders living alone on exposed barrier islands being the most vulnerable. The research suggests that family and household structures integrate several socio-demographic vulnerability indicators central to most social vulnerability assessments. Results indicate that future research and hazard mitigation policies should focus on families and households as core analytical units. Findings also suggest that recognizing the diversity of families and households is important to reducing vulnerability to natural hazards. 相似文献
70.
Recent research on the Mississippi margin indicates notable seasonal variation in seabed dynamics. During years with minimal tropical-system activity, sediments initially deposited from late spring to early fall are remobilized by wind-driven currents and wave energy during extra-tropical weather systems in the winter. This research reveals the profound significance of tropical cyclones on Louisiana Shelf sedimentation. The amount of material delivered to and advected across the shelf by recent tropical cyclones is considerably larger than that related to winter storm systems. In Fall 2004, the river-dominated shelf of Louisiana was impacted by three tropical systems in less than a month, including Hurricane Ivan. Ivan, with maximum sustained winds in excess of 74 m s−1 (144 knots) and a minimum measured central pressure of 910 mbar, was the eighth most intense Atlantic hurricane on record at the time. In order to assess the impact these tropical systems had on the continental margin west of the Mississippi delta, seabed samples were collected from box cores in October 2004 and analyzed for particle-reactive radionuclides 234Th, 7Be, and 210Pb. Radiochemical data and observations from X-radiographs indicate event-driven sediment deposits ranged from 4 to 30 cm on the shelf and 2–6 cm in the Mississippi Canyon. These deposits exhibit distinct radiochemical signatures and differ visually and texturally from the underlying sediment. The well-developed physical stratification and graded nature of the deposits observed in core X-radiographs suggests that the sediment could have been deposited from sediment-gravity flows. Inventories of 7Be and 7Be/234Thxs ratios reveal this series of cyclones transported considerably more material to the outer shelf and slope than periods of minimal tropical-system activity. When compared to seasonal depositional rates created by winter storms, tropical-cyclone-related event deposits on the middle and outer shelf are up to an order of magnitude greater in thickness. The number and thickness of these event deposits decrease with distance from the delta and suggest that only the most severe tropical systems are likely capable of redistributing significant quantities of sediment to more distal portions of the shelf and slope. These severe-event-driven deposits may account for as much as 75% of the sediment burial budget on decadal time scales within Mississippi Canyon. Higher than average tropical cyclone activity, predicted by the National Hurricane Center over the next decade, may be the major mechanism controlling sediment transport and deposition on the Mississippi River continental shelf and in Mississippi Canyon. 相似文献