Ensemble Generation For Hurricane Hazard Assessment Along The United
States' Atlantic Coast
Abstract
Scarcity of available records is a major hindrance in hurricane hazard
assessment. In addition, frequency analysis on maximum intensities of
all historical storms is incapable of analyzing very rare phenomena.
Ensemble generation is crucial for circumventing these difficulties,
targeted at this study. We will show here that ensembles like Sandy can
be statistically generated even by removing its trajectory from
historical records. We began with historical compilations of NOAA
National Climatic Data Center (NCDC) tropical cyclone (TC) database. TC
reaching a hurricane strength and making landfall in or passing close to
the United States were identified. The geographical area influenced by
these hurricanes was discretized and the parameters of Markov chains and
multivariate distributions were derived for each discretized area.
Synthetic tracks were generated using repetitive random draws from the
spatiotemporal distribution of historical genesis and storm motion,
conditioned by Markov chains for each 6-hour displacement. The proposed
algorithm is validated in macro and micro scales. In macro scale, tracks
coming within the specified radius of an area of interest were counted
for a given hurricane scale. The results revealed that the general
pattern of hits conforms well to historical observations. In micro
scale, the model was evaluated for Miami and New York City with quite
different hurricane climatology. The track generator produces a history
of potential wind and translational speeds for both of these regions as
well.