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Appendix E: HURASIM Model Description
HURASIM is a spatial simulation model of hurricane
structure and circulation for reconstructing estimated windforce and vectors of
past hurricanes. The HURASIM model
generates a matrix of storm characteristics (i.e., quadrant, windspeed, and
direction) within discrete spatial units and time intervals specified by the
user for any specific storm or set of storms. HURASIM recreates the spatial structure of past hurricanes based on a
tangential wind function, inflow angle offset, forward speed, and radius of
maximum winds. Figure E.1
shows the graphic user interface of the HURASIM model for a windfield
reconstruction of Hurricane Katrina (2005) making landfall southeast of New
Orleans, LA. Data input for
the model includes tracking information of storm position, latitude and
longitude, and maximum sustained wind speed every six hours or less. The model offers a suite of mathematical
functions and parameter sets for the tangential wind profile taken from other hurricane
studies (Harris, 1963; Bretschneiger and Tamaye, 1976; Neumann, 1987; Kjerfve
et al., 1986; Boose et al., 1994). The
user can specify the set of functions that provide more or less robust
constructions of the range and extent of estimated winds.
Model output is user-specified for given geographic
locations assigned by a given point or boundary area. Latitude and longitude for each study site
location was supplied to the model to create a log of hurricane activity at 15-minute
intervals for predicted winds above 30 mi/h for the period of record
(1851-2003). The model estimates a suite
of storm characteristics (i.e., quadrant, wind speed, and direction) within
discrete spatial units and time intervals specified by the user for designated
storms, years, and study site locations. Profiles of estimated wind conditions for a given site application are
stored by year and storm. Time intervals
of storm reposition and speed for this study were generated every 15
minutes. Minimum conditions of windspeed
or distance can be set to parse the data output if warranted. In this study, windspeed estimates for any
point or grid location were retained for further analysis if greater than 30 mi/h
or tropical depression status.
HURASIM has been used extensively for field and
modeling studies to relate biological response to hurricane forcing. HURASIM model output from Hurricane Andrew
was correlated with field data to construct data tables of damage probabilities
by site and species and to determine critical windspeeds and vectors of tree
mortality and injury (Doyle et al., 1995a, 1995b). HURASIM also has been applied to reconstruct
probable windfields of past hurricanes for remote field locations and
correlated with tree-ring growth patterns and direction of leaning trees and
downed logs (Doyle and Gorham, 1996). HURASIM also has been used to construct landscape templates of past
hurricane activity that are linked with landscape simulation models of coastal
habitat (Doyle and Girod, 1997).
References
Boose, E.R.,
1994: Hurricane impacts to tropical and
temperate forest landscapes. Ecological Monographs 64:369-400.
Bretschneigder, C.L. and E.E. Tamaye, 1976: Hurricane
wind and wave forecasting techniques. In: Proceedings of the 15th Coastal Engineering Conference,
held Honolulu, Hawaii,
July 11-17, (ASCE), Chapter 13, pages 202-237.
Doyle, T.W.,
B.D. Keeland, L.E. Gorham, and D.J. Johnson, 1995a: Structural impact of Hurricane Andrew on
forested wetlands of the Atchafalaya Basin
in coastal Louisiana. Journal
of Coastal Research 18:354-364.
Doyle, T.W., T.J.
Smith III, and M.B. Robblee, 1995b: Wind
damage effects of Hurricane Andrew on mangrove communities along the southwest
coast of Florida,
USA
. Journal
of Coastal Research 18: 144-159.
Doyle, T.W. and
L.E. Gorham, 1996: Detecting hurricane
impact and recovery from tree rings. In:
J.S. Dean, Meko, D.M., and Swetnam, T.W., Tree-Rings,
Environment and Humanity, Radiocarbon Press, Tucson,
Arizona. Radiocarbon 1996, pages 405-412.
Doyle, T.W. and
G. Girod, 1997: The frequency and
intensity of Atlantic hurricanes and their influence on the structure of south Florida
mangrove communities. Chapter 7.
pages 111-128. In: H. Diaz and R.
Pulwarty (eds.), Hurricanes, Climatic
Change and Socioeconomic Impacts: A Current Perspective, Westview
Press, New York, New York,
pages 325.
Harris, D.L., 1963: Characteristics
of the hurricane storm surge. U. S.
Department of Commerce, Technical Paper No. 48, Washington,
D.C., page 138.
Neumann, C.J., 1987: The National Hurricane Center risk analysis program (HURISK). NOAA Technical Memorandum NWS NHC 38, Washington
D.C., page 56.
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