Calendar

Dec
6
Thu
2012
John C. & Susan S.G. Wierman Lecture @ JHU Homewood, Hodson Hall 210
Dec 6 @ 1:30 pm – 2:30 pm
Richard L. Smith:  Attribution of Extreme Climatic Events

Superstorm Sandy is merely the most recent high-impact weather event to raise concerns about extreme weather events becoming more frequent or more severe. Previous examples include the western European heatwave of 2003, the Russian heatwave and the Pakistan floods of 2010, and the Texas heatwave of 2011. However, it remains an open question to what extent such events may be ““attributed”” to human influences such as increasing greenhouse gases. One way to answer this question is to run climate models under two scenarios, one including all the anthropogenic forcing factors (in particular, greenhouse gases) while the other is run only including the natural forcings (e.g. solar fluctuations) or control runs with no forcings at all. Based on the climate model runs, probabilities of the extreme event of interest may be computed under both scenarios, followed by the risk ratio or the ““fraction of attributable risk””, which has become popular in the climatology community as a measure of the human influence on extreme events. This talk will discuss statistical approaches to these quantities, including the use of extreme value theory as a method of quantifying the risk of extreme events, and Bayesian hierarchical models for combining the results of different climate models. This is joint work with Xuan Li (UNC) and Michael Wehner (Lawrence Berkeley Lab). Event flyer.

Oct
8
Thu
2015
Modeling Cyclone Risk and Seismic Building Vulnerability in Central America and the Caribbean @ Hackerman Hall B-17
Oct 8 @ 12:00 pm – 1:00 pm

Graduate Seminar: Modeling Cyclone Risk and Seismic Building Vulnerability in Central America and the Caribbean

This seminar will introduce two research projects applied to the Country Disaster Risk Profiles initiative of the World Bank: a hurricane hazard model and a probabilistic seismic vulnerability tool (PSVT). The windstorm hazard model is a novel approach which yields characterizations of windstorm activity (rate of occurrence, trajectory and spatial wind field) in the Central American region for use in natural risk assessment. The generative mechanism of storms is formulated as a superposition of stochastic processes whose joint opera;on yields synthetic cyclones activity in the region. The outcomes of the model match observed data acceptably well. A brief reference to the risk estimation procedure will be offered. Vulnerability functions estimate building damage caused by an acting hazard intensity. The PSVT is a software tool for creating vulnerability functions for seismic risk analysis. The approach estimates structural response of user-defined models subjected to ground acceleration signals integrating the equations of motion. Ground signals are realizations of random process models of site–specific ground motion hazard.

 

Speaker: Dr. Gonzalo Pita
Adjunct Assistant Scientist, Department of Civil Engineering, Johns Hopkins University; Sr. Natural Risk and Vulnerability Specialist, The World Bank

Center for Systems Science and Engineering