Inundation Testbed Component Progress Report 09/29/2011
Overview
The aim of the inundation component of the SURA testbed is to provide NOAA and other governmental
agencies meaningful guidance on the behavior (e.g., accuracy, robustness, execution speed) and
implementation requirements (e.g., resolution, parameterization, computer capacity) of models that are
presently in “operational use”, or that are under consideration for such use, for computing waves, storm
surge and inundation. We define “operational use” to cover a wide range of society-critical applications
including hindcasts (e.g., forensic failure studies); forecasts (e.g., 4x365 or event based forecasts); risk
assessment (e.g., National Flood Insurance Program studies); design (e.g., coastal structures or
protection systems) and emergency management (e.g., inundation atlases). In year one, substantial
effort has been devoted to assembling the data infrastructure and common methodologies required for
this component of the testbed, e.g., standardized file formats, skill assessment software, common
model grids, comprehensive model forcing data and observational data sets for skill assessment for two
domains, the Gulf of Maine with high resolution nesting in Scituate Harbor, MA, and the Gulf of Mexico
with enhanced resolution along the Louisiana / Texas coast. Comparative model runs are being analyzed
for tidal forcing and for two significant historical storms in each domain. The skill assessment and the
intra- / inter-model comparisons will help define model accuracy, implementation requirements, and
computational performance to assist operational users select and efficiently apply these models.
Gulf of Maine (GoM)/Scituate Harbor Component
This testbed component is comprised of a far field domain of the greater GoM with a nested highresolution domain covering Scituate, MA (Figure 1). Models are being evaluated for a month-long tidal
Fig. 1 Nested, Scituate inundation grid (left) and the GoM regional FVCOM grid (right). The larger area
model is used to drive the high resolution Scituate inundation model.
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simulation during May 2010 and for two extra-tropical storms (May 2005, April 2007) that caused
significant storm surge and flooding in the Scituate area. Models under evaluation are:
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the East Coast, extra-tropical SLOSH overseen by NOAA MDL, (Figure 2)
SLOSH run on PV2 hurricane basin grid covering southern New England by co-PI Slinn @ UF,
(Figure 2)
FVCOM (circulation, surge, inundation) coupled to SWAVE (waves) by co-PIs Chen @ UMass
Dartmouth and Beardsley @ WHOI,
SELFE (circulation, surge, inundation) coupled to WWM (waves) by co-PI Wang @ VIMS,
ADCIRC (circulation, surge, inundation) coupled to the unstructured SWAN model (waves) by
co-PI Westerink @ UND, and
WWIII and SWAN (waves) by co-PI Perrie @ BIO.
Fig. 2 SLOSH Grids, East Coast Extra Tropical Storm Surge (left), PV2 Hurricane Basin (right).
Progress since 6/19/2011:
FVCOM, SELFE and ADCIRC model runs have been completed for the Scituate domain for the May 2010
tidal simulation period and for both of the storms. Initial model comparisons between FVCOM, SELFE
and ADCIRC were confounded by time reference errors which led to significant phase errors between
the models. These have now been resolved and results for the May 2010 tidal simulation period are
show in Figure 3 and Table 1. Despite no attempt to implement a common frictional parameterization
Figure 3 model-data time series comparison for May 2010.
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Constituent
M2
N2
S2
O1
K1
Constituent
M2
N2
S2
O1
K1
Table 1a. Scituate tide amplitude comparison (5/1/2010 to 5/31/2010)
OBS
ADCIRC
Diff
FVCOM
Diff
SELFE
(m)
(m)
(m)
(m)
(m)
(m)
1.324
1.237
-0.087
1.238
-0.086
1.239
0.249
0.281
0.032
0.280
0.031
0.280
0.166
0.190
0.024
0.190
0.024
0.190
0.119
0.109
-0.010
0.110
-0.009
0.109
0.136
0.128
-0.008
0.128
-0.008
0.128
Diff
(m)
-0.085
0.031
0.024
-0.010
-0.008
Table 1b. Scituate tide phase comparison (5/1/2010 to 5/31/2010)
OBS
ADCIRC
Diff
FVCOM
Diff
SELFE
(deg)
(deg)
(deg)
(deg)
(deg)
(deg)
103.46
101.62
-1.84
101.66
-1.80
101.97
68.62
69.58
0.96
69.51
0.89
69.87
141.30
152.58
11.28
152.81
11.51
153.17
187.13
183.49
-3.64
183.56
-3.57
183.59
198.77
193.53
-5.24
193.48
-5.29
193.93
Diff
(deg)
-1.49
1.25
11.87
-3.54
-4.84
amongst the models, all produce virtually identical tidal results. This is due to the small size of the
Scituate domain. Harmonic analysis of tidal results for the May 2005 and April 2007 storm periods
yields similar conclusions. Model timeseries at multiple locations and inundation surfaces within the
Scituate domain are currently being analyzed during the two storm periods to further discriminate
differences in model behavior.
Efforts are continuing to systematically compare WWIII, SWAN and SWAVE on the larger GoM domain.
These include comparisons between 1-d and 2-d model spectra and buoy data and also analysis of
model sensitivity to parameterizations such as the number of frequencies and propagation directions,
physics packages, etc.
No further progress has been made for the SLOSH model / basins.
The question previously reported concerning the averaging time interval that the meteorological model
wind velocity output corresponds to and that should be used to force the wave and surge models
remains and will be pursued in more detail in year 2 of the testbed; its resolution should provide
important guidance for the operational use of wave and surge models.
Gulf of Mexico (GoMx) Component
This testbed component is comprised of a GoMx wide domain with enhanced resolution along the LA/TX
coasts (Figure 4). Models are being evaluated for tidal forcing and for hurricanes Rita (2005) and Ike
(2008), both of which caused significant flooding and inland penetration of water in the LA/TX region.
Models under evaluation are:
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Fig. 4 Gulf of Mexico Component Grid.
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the tropical SLOSH model on 4 available domains (Galveston 2, Galveston 3-higher res, Sabine
Pass, Gulf of Mexico ETSS) (Figure 5) in the GoMx coupled to the SWAN (waves) model by co-PI
Slinn @ UF,
FVCOM (circulation, surge, inundation) coupled to SWAVE (waves) by co-PI Li @ LSU,
FVCOM (circulation, surge, inundation) coupled to SWAN (waves) by co-PI Weisberg @ USF,
SELFE (circulation, surge, inundation) coupled to WWM (waves) by co-PI Wang @ VIMS, and
ADCIRC (circulation, surge, inundation) coupled to the unstructured SWAN model (waves) by
co-PI Westerink @ UND.
Progress since 6/19/2011:
Complete QA/QC and uploading of observational data for hurricanes Ike and Rita. Hurricane Rita has
several hundred observed hydrographs and Ike has over 700 observed hydrographs that can be used for
model evaluation.
Tidal comparisons have been finalized between ADCIRC, FVCOM and SELFE and 59 stations having tidal
constituent data using 2D model formulations with common, spatially varying, Manning’s n bottom
friction. The skill of the three models was quite similar, although ADCIRC appeared to give generally
larger tidal amplitudes than FVCOM and SELFE.
A base set of comparison has been completed between ADCIRC, FVCOM, SELFE and SLOSH and
observations for Hurricane Ike using 2D model formulations, including tides, without waves and with
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Fig. 5 SLOSH Grids – Gulf of Mexico Extra Tropical Storm Surge (top), Galveston Hurricane Basin (left),
Sabine Pass Hurricane Basin (right).
common, spatially varying, Manning’s n bottom friction. A sample of the results are presented in Figure
6 and typically show that ADCIRC and SELFE track each other closely, FVCOM is below and SLOSH gives
the lowest surge levels. In addition, SLOSH does not capture the 2-3m geostrophically driven waterlevel
setup that occurs on much of the western Louisiana and northern Texas shelf in the 24 hrs leading up to
the main Ike surge. This contributes to the overall under prediction of the main surge.
A full set of model and data comparisons can be seen at the website:
http://www.nd.edu/~coast/work/Pages/SURAIOOS/SURAIOOS_MAP.htm These results are being
further analyzed using IMEDS to determine quantitative skill measures.
Additional Ike runs have been completed for ADCIRC and FVCOM including wave forcing and using 3D vs
2D physics and will be included in the analyses.
Runs have also been completed using ADCIRC on a grid with approximately 20x the resolution of the
SURA common grid, Figure 7. Comparisons with this grid are being evaluated to determine the
implications of using substantially greater grid resolution on the model results.
A base case set of wave model parameters has been defined to allow systematic comparisons between
these models as well as the surge comparisons.
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Fig. 6 Comparisons between ADCIRC, SELFE, FVCOM, SLOSH and observations at 4 locations for
Hurricane Ike. Runs do not include wave effects. SLOSH OWI uses the same wind forcing as the other
models. SLOSH 3 uses the parametric wind model embedded in SLOSH.
Fig. 7 Comparisons in the Galveston Bay region between inundation areas computed for Hurricane Ike
using ADCIRC on the SURA testbed common grid and a grid with approximately 20x the resolution.
Turquoise represents areas that were water covered using both grids (including ocean and shelf
waters), magenta areas were only wet on the high resolution grid and blue areas were only wet on the
common grid.
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Model Interoperability / IMEDS Skill Assessment
A converter has been developed by CI team member Davis @ UF to generate SLOSH output in IMEDS
standard ASCII format.
An IMEDS development meeting was held at ASA on 20 June 2011 from which a comprehensive
development plan has been completed. This plan allows for the establishment of two primary
components to IMEDS: 1. Desktop Tool and 2. MATLAB Function Library. The function library will allow
independent MATLAB applications to be written that have access to the core computation capabilities
within IMEDS. The Desktop tool will provide a graphical user interface (GUI) to the function library. The
GUI will have a variety of enhanced features including a map interface to results.
Due to the growing usage and popularity of IMEDS, USACE is providing the (in-kind) support necessary
to develop the IMEDS improvements recommended by the SURA program and briefly described above.
This will include the development of a polished, professional desktop application with tutorial-based
activities to provide the user guidance on how to perform model skill assessment and comparisons with
observations and other model results. The improved IMEDS will be delivered with a mature and tested
installation package for common operating systems.
Dissemination
Inundation testbed results were presented and discussed in depth at the testbed all hands meeting in
June 2011. The meeting was well attended by representatives from multiple operational federal
agencies.
Rick Luettich and Bob Beardsley presented posters covering results from the inundation testbed at the
Coastal Modeling Gordon Conference at the end of June 2011.
Linda Akli presented a poster covering results from the inundation testbed at the TeraGrid11
Conference in July.
John Harding presented material from the inundation testbed as part of a testbed overview
presentation he gave at the Coastal Zone Conference in July 2011.
Jamie Rhome, who leads the storm surge group at the National Hurricane Center and is part of the
inundation testbed team, invited inundation lead, Rick Luettich, to visit at the NHC on Sept 6-8 to get a
first hand appreciation of how hurricane forecasting is done and of the operations of the storm surge
group. It was a great time to visit since there were several active storms in the Atlantic basin. While
there Luettich presented a seminar covering recent advancements in storm surge modeling with
emphasis on the inundation testbed. The seminar was attended by the NHC Director, Bill Reed,
forecasters, members of the storm surge group and colleagues from Florida International University (the
NHC is on the FIU campus).
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