Storm Surge Flood Hazards of Hurricane Katrina 2005
Abstract. Flooding due to hurricane storm surge is one of the most damaging natural disasters in tropical and sub-tropical coastal regions. Storm surge peril can cause catastrophic loss to coastal properties and loss of life. Estimated hurricane flood risk is often statistically-based and relies on historical data. It provides catastrophic loss and risk information for the event as a whole, but lacks geographical detail. The purpose of this study is to analyze hurricane-induced storm surge flood damage using a grid-based numerical model. Storm surge flood damage due to Hurricane Katrina 2005 is presented as a case study. In order to analyze the resulting hazard from Hurricane Katrina, the United States National Weather Service's operational storm surge model, SLOSH (Sea, Lake and Overland Surges from Hurricanes) was used to predict the maximum storm surge surface using track data from meteorological observations. Local inundation is computed using the flood water depth with the ground elevation above the mean sea level. Residential exposure is estimated using total number of housing units damaged by flood water in each US census block in a grid of 0.01 by 0.01 degrees for hurricane Katrina in 2005. The modeled results for the storm surge inundation and the estimated number of housing units damaged by hurricane Katrina are compared with the extensive field observations by US Geological Survey and FEMA in the counties along the Gulf Coast in the three impacted states of Alabama, Mississippi and Louisiana. The modeled surge results are compared and contrasted with high water mark observations, where available. Storm surge losses in residential construction are highly sensitive to location and are best evaluated at a fine spatial resolution. This paper presents the analysis of the catastrophic flood risk based on the magnitude of hurricane storm surge flood depth on a local scale of US census blocks. The framework presented here is analytically-derived and can be used to provide future hurricane flood information with geographic details for other regions along the US Gulf and Atlantic coastal line.
Tsunami Hazard in the Algerian Coastline
The Algerian coastline is located at the border between the African and the Eurasian tectonic plates. The collision between these two plates is approximately 4 to 7 mm/yr. The Alps and the tellian Atlas result from this convergence. Historical and present day data show the occurrence of earthquakes with magnitude up to 7 degrees on Richter scale in the northern part of the country. Cities were destroyed and the number of victims reached millions of people. Recently, small seismic waves generated by a destructive earthquake (Epicenter: 36.90N, 3.71E; Mw=6.8; Algeria, 2003, NEIC) were recorded in the French and Spanish coasts. This event raised again the issue of tsunami hazard in western Mediterranean region. For the Algerian study case, the assessment of seismic and tsunami hazard is a matter of great interest because of fast urban development of cities like Algiers. This study aims to provide scientific arguments to help in the elaboration of the Mediterranean tsunami alert program. This is a real complex issue because (1) the western part of the sea is narrow, (2) constructions on the Algerian coastline do not respect safety standards and (3) the seismic hazard is important. The present work is based on a numerical modeling approach. Firstly, a database is created to gather and list information related to seismology, tectonic, abnormal sea level's variations recorded/observed, submarine and coastal topographic data for the western part of the Mediterranean margin. This database helped to propose series of scenario that could trigger tsunami in the Mediterranean sea. Seismic moment, rake and focal depth are the major parameters that constrain the modeling input seismic data. Then, the undersea earthquakes modeling and the seabed deformations are computed with a program adapted from the rngchn code based on Okada's analytic equations. The last task of this work consisted to calculate the initial water surface displacement and simulate the triggered tsunami. Generation and propagation of induced seismic waves were estimated with another program adapted from the swan code for the resolution of the hydrodynamic shallow water equations. The results obtained will be firstly presented. Then, based on seismic waves travel times and run up height values, a large discussion will focus on the tsunami alert program for cities marked by fast urban development.
Modeling and Economics of Air Pollution Abatement Policies in the Valley of Mexico
Using meteorological and air quality models it has been possible to study the air pollution phenomenon in the Valley of Mexico. This capability together with the development of a system to obtain vehicular emissions in Mexico City, allow estimating the possible reductions in Ozone concentrations because of the introduction of new car technologies such as Hybrid Electric Vehicles (HEVīs) in Mexico City. Using this data together with epidemiological studies, a prediction on avoided cases of mortality and morbidity due to reduction in ambient concentrations of Ozone are obtained. Monetary values of these reductions are calculated valuating this car technology change. This methodology will allow the prediction on health benefits because of the introduction of bio fuels and other vehicular technologies in Mexico City.
MCCM-WEPS: A Computational Tool to Study and Evaluate Air Pollution by Dust Particles over Mexico City.
Since natural dust emissions are an important factor in the air quality of Mexico City, a modeling effort to quantify and locate its sources and evaluate their impact on the population is presented. The system obtained from coupling Multiscale Climate and Chemistry Model (MCCM) and Wind Erosion Prediction System (WEPS) was developed to study the dispersion of particles from natural sources (unprotected soils) of the mostly dry Lake of Texcoco and agricultural lands located around Mexico City. As a result of this research we developed a system with the capability of modeling the phenomenon of air pollution by natural particles emitted by wind erosion and to generate case study scenarios useful to propose control policies. Some case studies and their economical impact on public health benefits are presented.
Strong Interaction between Dust and Himalayan Snow Cover
Dust storms are commonly observed over the Indo-Gangetic plains prior to the monsoon season. These dust storms originate from Arabia peninsula and transported to the Indo-Gangetic plains and reach up to Himalayan region. Dust storms interact all along its path, and affect the ocean and earth surface, and degrade the air quality. Depending upon its trajectory, dust storms cover the snow surface in the Himalayan region. Interaction of the dust and snow cover is found to be very strong that affect the melting of the snow cover. Detailed analysis of multi sensor data will be presented that show strong interaction of dust storm and snow cover, this has lead to the depletion of the areal extent of the snow cover especially in the western parts of the Himalayan region.