Dataset Identification:
Resource Abstract:
- description: Projected Hazard: Model-derived significant wave height (in meters) for the given storm condition and sea-level
rise (SLR) scenario. Model Summary: The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) over
large geographic scales (100s of kilometers) of storm-induced coastal flooding and erosion for both current and future sea-level
rise (SLR) scenarios. CoSMoS v3.0 for Southern California shows projections for future climate scenarios (sea-level rise and
storms) to provide emergency responders and coastal planners with critical storm-hazards information that can be used to increase
public safety, mitigate physical damages, and more effectively manage and allocate resources within complex coastal settings.
Phase I data for Southern California include flood-hazard information for the coast from the border of Mexico to Pt. Conception.
Changes from the initial November 2015 release may be reflected in small areas. Data are complete for the information presented
but are considered preliminary; additional changes may be reflected with model improvements made for the Phase II data release
in summer 2016. Details: Model background: The CoSMoS model comprises three tiers. Tier I consists of one Delft3D hydrodynamics
FLOW grid for computation of tides, water level variations, flows, and currents and one SWAN grid for computation of wave
generation and propagation across the continental shelf. The FLOW and SWAN models are two-way coupled so that tidal currents
are accounted for in wave propagation and growth and conversely, so that orbital velocities generated by waves impart changes
on tidal currents. The Tier I SWAN and FLOW models consist of identical structured curvilinear grids that extend from far
offshore to the shore and range in resolution from 0.5 km in the offshore to 0.2 km in the nearshore. Spatially varying astronomic
tidal amplitudes and phases and steric rises in water levels due to large-scale effects (for example, a prolonged rise in
sea level) are applied along all open boundaries of the Tier I FLOW grid. Winds (split into eastward and northward components)
and sea-level pressure (SLP) fields from CaRD10 (Dr. Dan Cayan, Scripps Institute of Oceanography, San Diego, California,
written commun., 2014) that vary in both space and time are applied to all grid cells at each model time-step. Deep-water
wave conditions, applied at the open boundaries of the Tier I SWAN model runs, were projected for the 21st century Representative
Concentration Pathway (RCP) 4.5 climate scenario (2011-2100) using the WaveWatch III numerical wave model (Tolman and others,
2002) and 3-hourly winds from the GFDL-ESM2M Global Climate Model (GCM). Tier II provides higher resolution near the shore
and in areas that require greater resolution of physical processes (such as bays, harbors, and estuaries). A single nested
outer grid and multiple two-way coupled domain decomposition (DD) structured grids allow for local grid refinement and higher
resolution where needed. Tier II was segmented into 11 sections along the Southern California Bight, to reduce computation
time and complete runs within computational limitations. Water-level and Neumann time-series, extracted from Tier I simulations,
are applied to the shore-parallel and lateral open boundaries of each Tier II sub-model outer grid respectively. Several of
the sub-models proved to be unstable with lateral Neumann boundaries; for those cases one or both of the lateral boundaries
were converted to water-level time-series or left unassigned. The open-boundary time-series are extracted from completed Tier
I simulations so that there is no communication from Tier II to Tier I. Because this one-way nesting could produce erroneous
results near the boundaries of Tier II and because data near any model boundary are always suspect, Tier II sub-model extents
were designed to overlap in the along-coast direction. In the landward direction, Tier II DD grids extend to the 10-m topographic
contour; exceptions exist where channels (such as the Los Angeles River) or other low-lying regions extend very far inland.
Space- and time-varying wind and SLP fields, identical to those used in Tier I simulations, are applied to all Tier II DD
grids to allow for wind-setup and local inverse barometer effects (IBE, rise or depression of water levels in response to
atmospheric pressure gradients). A total of 42 time-series fluvial discharges are included in the Tier II FLOW domains in
an effort to simulate exacerbated flooding caused by backflow at the confluence of high river seaward flows and elevated coastal
surge levels migrating inland. Time-varying fluvial discharges are applied either at the closed boundaries or distributed
as point sources within the relevant model domains. Wave computations are accomplished with the SWAN model using two grids
for each Tier II sub-model: one larger grid covering the same area as the outer FLOW grid and a second finer resolution two-way
coupled nearshore nested grid. The nearshore grid extends from approximately 800-1,000 m water depth up to 8-10 m elevations
onshore. The landward extension is included to allow for wave computations of the higher SLR scenarios. Time- and space-varying
2D wave spectra extracted from previously completed Tier I simulations are applied approximately every kilometer along the
open boundaries of the outer Tier II sub-model SWAN grids. The same space- and time-varying wind fields used in Tier I simulations
are also applied to both Tier II SWAN grids to allow for computation of local wave generation. Tier III for the entire Southern
California Bight consists of 4,802 cross-shore transects (CST) spaced approximately 100 m apart in the along-shore direction.
The profiles extend from the -15 m isobath to at least 10 m above NAVD88. The CSTs are truncated for cases where a lagoon
or other waterway exists on the landward end of the profile. Time-varying water levels and wave parameters (significant wave
heights, Hs; peak periods, Tp; and peak incident wave directions, Dp), extracted from Tier II grid cells that coincide with
the seaward end of the CSTs, are applied at the open boundary of each CST. The XBeach model is run in a hydrostatic (no vertical
pressure gradients) mode including event-based morphodynamic change. Wave propagation, two-way wave-current interaction, water-level
variations, and wave runup are computed at each transect. XBeach simulations are included in the CoSMoS model to account for
infragravity waves that can significantly extend the reach of wave runup (Roelvink and others, 2009) compared to short-wave
incident waves. The U.S. west coast is particularly susceptible to infragravity waves at the shore due to breaking of long-period
swell waves (Tp > 15). Resulting water levels (WLs) from both Delft3D (high interest bays and marshes) and open-coast XBeach
(CSTs) were spatially combined and interpolated to a 10 m grid. These WL elevations are differenced from the originating 2
m digital elevation model (DEM) to determine final flooding extent and depth of flooding. Events: The model system is run
for pre-determined scenarios of interest such as the 1-yr or 100-yr storm event in combination with sea-level rise. For Phase
I, only the 100-year storm is run. Storms are first identified from time-series of total water level proxies (TWLpx) at the
shore. TWLpx are computed for the majority of the 21st century (2010-2100), assuming a linear super-position of the major
processes that contribute to the overall total water level. TWLpx time-series are then evaluated for extreme events, which
define the boundary conditions for subsequent modeling with CoSMoS. Multiple 100-yr events are determined (varying Hs, Tp,
Dp) and used for multiple model runs to better account for regional and directional flooding affects. Model results are combined
and compiled into scenario-specific composites of flood projection. Digital Elevation Model (DEM): Our seamless, topobathymetric
digital elevation model (DEM) was based largely upon the Coastal California TopoBathy Merge Project DEM, with some modifications
performed by the USGS Earth Resources Observation and Science (EROS) Center to incorporate the most recent, high-resolution
topographic and bathymetric datasets available. Topography is derived from bare-earth light detection and ranging (lidar)
data collected in 2009-2011 for the CA Coastal Conservancy Lidar Project and bathymetry from 2009-2010 bathymetric lidar as
well as acoustic multi- and single-beam data collected primarily between 2001 and 2013. The DEM was constructed to define
the shape of nearshore, beach, and cliff surfaces as accurately as possible, utilizing dozens of bathymetric and topographic
data sets. These data were used to populate the majority of the Tier II grids and generate initial profiles of the 4,802 CSTs
used for Tier III XBeach modeling. All data are referenced to NAD83 horizontal datum and NAVD88 vertical datum. Data for Tiers
II and III are projected in UTM, zone 11. Outputs include: Projected wave height for the 100-year storm and 0.0 m sea-level
rise scenario. Data correspond to the near-shore region including areas vulnerable to coastal flooding due to storm surge,
sea-level anomalies, tide elevation, and wave run-up during the same storm and sea-level rise simulation. References Cited:
Roelvink, J.A., Reniers, A., van Dongeren, A.R., van Thiel de Vries, J., McCall, R., and Lescinski, J., 2009, Modeling storm
impacts on beaches, dunes and barrier islands: Coastal Engineering, v. 56, p. 1,133€“1,152, doi:10.1016/j.coastaleng.2009.08.006.
Tolman, H.L., Balasubramaniyan, B., Burroughs, L.D., Chalikov, D.V., Chao, Y.Y., Chen H.S., Gerald, V.M., 2002, Development
and implementation of wind generated ocean surface wave models at NCEP: Weather and Forecasting, v. 17, p. 311-333.; abstract:
Projected Hazard: Model-derived significant wave height (in meters) for the given storm condition and sea-level rise (SLR)
scenario. Model Summary: The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) over large geographic
scales (100s of kilometers) of storm-induced coastal flooding and erosion for both current and future sea-level rise (SLR)
scenarios. CoSMoS v3.0 for Southern California shows projections for future climate scenarios (sea-level rise and storms)
to provide emergency responders and coastal planners with critical storm-hazards information that can be used to increase
public safety, mitigate physical damages, and more effectively manage and allocate resources within complex coastal settings.
Phase I data for Southern California include flood-hazard information for the coast from the border of Mexico to Pt. Conception.
Changes from the initial November 2015 release may be reflected in small areas. Data are complete for the information presented
but are considered preliminary; additional changes may be reflected with model improvements made for the Phase II data release
in summer 2016. Details: Model background: The CoSMoS model comprises three tiers. Tier I consists of one Delft3D hydrodynamics
FLOW grid for computation of tides, water level variations, flows, and currents and one SWAN grid for computation of wave
generation and propagation across the continental shelf. The FLOW and SWAN models are two-way coupled so that tidal currents
are accounted for in wave propagation and growth and conversely, so that orbital velocities generated by waves impart changes
on tidal currents. The Tier I SWAN and FLOW models consist of identical structured curvilinear grids that extend from far
offshore to the shore and range in resolution from 0.5 km in the offshore to 0.2 km in the nearshore. Spatially varying astronomic
tidal amplitudes and phases and steric rises in water levels due to large-scale effects (for example, a prolonged rise in
sea level) are applied along all open boundaries of the Tier I FLOW grid. Winds (split into eastward and northward components)
and sea-level pressure (SLP) fields from CaRD10 (Dr. Dan Cayan, Scripps Institute of Oceanography, San Diego, California,
written commun., 2014) that vary in both space and time are applied to all grid cells at each model time-step. Deep-water
wave conditions, applied at the open boundaries of the Tier I SWAN model runs, were projected for the 21st century Representative
Concentration Pathway (RCP) 4.5 climate scenario (2011-2100) using the WaveWatch III numerical wave model (Tolman and others,
2002) and 3-hourly winds from the GFDL-ESM2M Global Climate Model (GCM). Tier II provides higher resolution near the shore
and in areas that require greater resolution of physical processes (such as bays, harbors, and estuaries). A single nested
outer grid and multiple two-way coupled domain decomposition (DD) structured grids allow for local grid refinement and higher
resolution where needed. Tier II was segmented into 11 sections along the Southern California Bight, to reduce computation
time and complete runs within computational limitations. Water-level and Neumann time-series, extracted from Tier I simulations,
are applied to the shore-parallel and lateral open boundaries of each Tier II sub-model outer grid respectively. Several of
the sub-models proved to be unstable with lateral Neumann boundaries; for those cases one or both of the lateral boundaries
were converted to water-level time-series or left unassigned. The open-boundary time-series are extracted from completed Tier
I simulations so that there is no communication from Tier II to Tier I. Because this one-way nesting could produce erroneous
results near the boundaries of Tier II and because data near any model boundary are always suspect, Tier II sub-model extents
were designed to overlap in the along-coast direction. In the landward direction, Tier II DD grids extend to the 10-m topographic
contour; exceptions exist where channels (such as the Los Angeles River) or other low-lying regions extend very far inland.
Space- and time-varying wind and SLP fields, identical to those used in Tier I simulations, are applied to all Tier II DD
grids to allow for wind-setup and local inverse barometer effects (IBE, rise or depression of water levels in response to
atmospheric pressure gradients). A total of 42 time-series fluvial discharges are included in the Tier II FLOW domains in
an effort to simulate exacerbated flooding caused by backflow at the confluence of high river seaward flows and elevated coastal
surge levels migrating inland. Time-varying fluvial discharges are applied either at the closed boundaries or distributed
as point sources within the relevant model domains. Wave computations are accomplished with the SWAN model using two grids
for each Tier II sub-model: one larger grid covering the same area as the outer FLOW grid and a second finer resolution two-way
coupled nearshore nested grid. The nearshore grid extends from approximately 800-1,000 m water depth up to 8-10 m elevations
onshore. The landward extension is included to allow for wave computations of the higher SLR scenarios. Time- and space-varying
2D wave spectra extracted from previously completed Tier I simulations are applied approximately every kilometer along the
open boundaries of the outer Tier II sub-model SWAN grids. The same space- and time-varying wind fields used in Tier I simulations
are also applied to both Tier II SWAN grids to allow for computation of local wave generation. Tier III for the entire Southern
California Bight consists of 4,802 cross-shore transects (CST) spaced approximately 100 m apart in the along-shore direction.
The profiles extend from the -15 m isobath to at least 10 m above NAVD88. The CSTs are truncated for cases where a lagoon
or other waterway exists on the landward end of the profile. Time-varying water levels and wave parameters (significant wave
heights, Hs; peak periods, Tp; and peak incident wave directions, Dp), extracted from Tier II grid cells that coincide with
the seaward end of the CSTs, are applied at the open boundary of each CST. The XBeach model is run in a hydrostatic (no vertical
pressure gradients) mode including event-based morphodynamic change. Wave propagation, two-way wave-current interaction, water-level
variations, and wave runup are computed at each transect. XBeach simulations are included in the CoSMoS model to account for
infragravity waves that can significantly extend the reach of wave runup (Roelvink and others, 2009) compared to short-wave
incident waves. The U.S. west coast is particularly susceptible to infragravity waves at the shore due to breaking of long-period
swell waves (Tp > 15). Resulting water levels (WLs) from both Delft3D (high interest bays and marshes) and open-coast XBeach
(CSTs) were spatially combined and interpolated to a 10 m grid. These WL elevations are differenced from the originating 2
m digital elevation model (DEM) to determine final flooding extent and depth of flooding. Events: The model system is run
for pre-determined scenarios of interest such as the 1-yr or 100-yr storm event in combination with sea-level rise. For Phase
I, only the 100-year storm is run. Storms are first identified from time-series of total water level proxies (TWLpx) at the
shore. TWLpx are computed for the majority of the 21st century (2010-2100), assuming a linear super-position of the major
processes that contribute to the overall total water level. TWLpx time-series are then evaluated for extreme events, which
define the boundary conditions for subsequent modeling with CoSMoS. Multiple 100-yr events are determined (varying Hs, Tp,
Dp) and used for multiple model runs to better account for regional and directional flooding affects. Model results are combined
and compiled into scenario-specific composites of flood projection. Digital Elevation Model (DEM): Our seamless, topobathymetric
digital elevation model (DEM) was based largely upon the Coastal California TopoBathy Merge Project DEM, with some modifications
performed by the USGS Earth Resources Observation and Science (EROS) Center to incorporate the most recent, high-resolution
topographic and bathymetric datasets available. Topography is derived from bare-earth light detection and ranging (lidar)
data collected in 2009-2011 for the CA Coastal Conservancy Lidar Project and bathymetry from 2009-2010 bathymetric lidar as
well as acoustic multi- and single-beam data collected primarily between 2001 and 2013. The DEM was constructed to define
the shape of nearshore, beach, and cliff surfaces as accurately as possible, utilizing dozens of bathymetric and topographic
data sets. These data were used to populate the majority of the Tier II grids and generate initial profiles of the 4,802 CSTs
used for Tier III XBeach modeling. All data are referenced to NAD83 horizontal datum and NAVD88 vertical datum. Data for Tiers
II and III are projected in UTM, zone 11. Outputs include: Projected wave height for the 100-year storm and 0.0 m sea-level
rise scenario. Data correspond to the near-shore region including areas vulnerable to coastal flooding due to storm surge,
sea-level anomalies, tide elevation, and wave run-up during the same storm and sea-level rise simulation. References Cited:
Roelvink, J.A., Reniers, A., van Dongeren, A.R., van Thiel de Vries, J., McCall, R., and Lescinski, J., 2009, Modeling storm
impacts on beaches, dunes and barrier islands: Coastal Engineering, v. 56, p. 1,133€“1,152, doi:10.1016/j.coastaleng.2009.08.006.
Tolman, H.L., Balasubramaniyan, B., Burroughs, L.D., Chalikov, D.V., Chao, Y.Y., Chen H.S., Gerald, V.M., 2002, Development
and implementation of wind generated ocean surface wave models at NCEP: Weather and Forecasting, v. 17, p. 311-333.
Citation
- Title CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 0.0 m: wave-hazard
projections.
-
- creation Date
2018-06-08T00:09:01.186024
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2018-08-06T23:11:45Z
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- notes: This metadata record was generated by an xslt transformation from a dc metadata record; Transform by Stephen M. Richard, based
on a transform by Damian Ulbricht. Run on 2018-08-06T23:11:45Z
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pointOfContact
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CINERGI Metadata catalog
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- electronic Mail Address cinergi@sdsc.edu
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urn:dciso:metadataabout:0b519d66-be5e-4c75-882c-e985e788361b
Metadata record format is ISO19139 XML (MD_Metadata)