improved storm surge model prediction using a high resolution unstructured grid
DESCRIPTION
Improved Storm Surge Model Prediction Using a High Resolution Unstructured Grid. Jian Shen Virginia Institute of Marine Sciences College of William and Mary. Unstructured 3D Model (UnTRIM). - PowerPoint PPT PresentationTRANSCRIPT
Improved Storm Surge Model Improved Storm Surge Model Prediction Using a High Resolution Prediction Using a High Resolution
Unstructured Grid Unstructured Grid
Jian ShenJian ShenVirginia Institute of Marine SciencesVirginia Institute of Marine Sciences
College of William and MaryCollege of William and Mary
Unstructured 3D Model (UnTRIM)Unstructured 3D Model (UnTRIM)
• “UnTRIM” incorporates an Unstructured grid into TRIM model (Tidal, Residual, Intertidal Mudflat), originally developed by Vincenzo Casulli
• It simulates three-dimensional hydrodynamic and transport processes
• It uses an orthogonal unstructured grid• It conserves mass locally as well as globally • It uses Eulerian-Langangian transport scheme • It employs semi-implicit finite difference and finite
volume method- very efficient computationally• It is capable of simulating wet-dry processes
OrthogonalOrthogonal Grid Structure Grid Structure
• Use polygons to represent a prototype estuary (3-, 4-, 5-sides)
• Better fitting complicated geometry in estuarine and coastal environment
• Using orthogonal grid simplifies the numerical algorithm
Grid StructureGrid Structure
Water depth
Isabel Simulation StudiesIsabel Simulation Studies
• Study the accuracy of model prediction of Isabel forced by a stationary, circular wind model
• Compare model prediction with and without simulating inundation
• Study influence of open boundary condition specification on surge simulation– still boundary condition vs. inverse pressure adjust
boundary condition •
Model GridsModel Grids
Surface element =121338
Surface element =239541
Grid layout at York and James RiversGrid layout at York and James Rivers
Gloucester Pt.
0 2 km
0 2 km
Model CalibrationModel Calibration
• Calibrate model for tide
forced by 9 tidal constituents M2, S2, K1, O1, Q1, K2, N2, M4, and M6
• Model was run for 3 months and the results of the last 29 days were used for computing tidal harmonics
• Timestep = 5 min.•
Tidal Simulation (MTidal Simulation (M22 tide) tide)
Tidal Simulation (KTidal Simulation (K11))
Observation StationsObservation Stations
Tidal Constituents Comparison Tidal Constituents Comparison (Amplitude)(Amplitude)
Amplitude is in mObservations are based on 1992 data
ModeledObs. ModeledObs. ModeledObs. ModeledObs. ModeledObs. ModeledObs.Stations
Bay Bridge 0.38 0.37 0.06 0.07 0.09 0.09 0.07 0.06 0.05 0.05 0.01 0.02Kiptopeke 0.38 0.37 0.06 0.07 0.08 0.09 0.07 0.06 0.05 0.05 0.01 0.02Sewells Pt. 0.35 0.35 0.06 0.06 0.08 0.08 0.06 0.06 0.05 0.04 0.01 0.02
Gloucester Pt. 0.34 0.33 0.05 0.06 0.07 0.08 0.05 0.05 0.04 0.04 0.01 0.02W indmill Point 0.17 0.16 0.03 0.03 0.04 0.04 0.04 0.03 0.02 0.02 0.01 0.01Lewisetta 0.18 0.17 0.04 0.03 0.04 0.04 0.03 0.02 0.02 0.02 0.02 0.01Solomons Isaland 0.17 0.16 0.03 0.02 0.03 0.04 0.04 0.03 0.03 0.02 0.02 0.01Cambridge 0.24 0.22 0.04 0.03 0.05 0.05 0.06 0.05 0.05 0.04 0.03 0.01Annapolis 0.12 0.13 0.02 0.02 0.03 0.03 0.06 0.06 0.05 0.04 0.01 0.01Baltimore 0.16 0.14 0.03 0.02 0.04 0.03 0.07 0.07 0.06 0.05 0.02 0.01Tolchester Beach 0.18 0.16 0.04 0.02 0.04 0.04 0.08 0.07 0.06 0.05 0.02 0.01
O1 K2M2 S2 N2 K1
Tidal Constituents Comparison (phase)Tidal Constituents Comparison (phase)
ModeledObs. ModeledObs. ModeledObs. ModeledObs. ModeledObs. ModeledObs.
Bay Bridge 99.5 99.5 75.1 75.1 39.4 39.4 199.3 199.3 268.3 268.3 224.7 224.7Kiptopeke 112.0 110.4 79.6 85.6 51.1 49.6 206.4 207.0 275.0 273.7 193.4 235.4Sewells Pt. 122.7 125.4 93.1 101.1 62.8 66.2 211.5 213.4 279.4 281.6 194.6 252.4Gloucester Pt. 130.6 131.9 101.8 105.6 71.3 72.8 215.4 211.3 283.0 281.4 163.3 259.3W indmill Point 181.9 196.4 152.8 166.9 119.1 130.9 241.7 242.9 312.7 313.5 298.9 15.6Lewisetta 254.0 253.9 203.8 231.0 185.6 189.0 289.0 288.3 360.7 355.4 324.8 18.5Solomons Isaland 270.9 276.5 211.9 254.3 202.7 210.2 319.0 329.1 24.4 27.4 325.1 43.8Cambridge 320.7 336.3 257.5 311.1 255.9 271.6 341.3 355.3 40.4 46.8 352.8 105.9Annapolis 7.1 8.8 319.6 348.0 300.8 305.9 0.9 10.1 56.3 65.2 58.9 133.0Baltimore 56.1 53.9 4.9 37.4 345.4 348.3 14.1 20.8 67.6 75.1 120.0 173.9Tolchester Beach 59.8 64.3 3.4 36.9 348.0 356.6 12.4 18.3 65.8 72.3 120.0 184.2
M2 S2Station N2 K1 O1 K2
Phase is in degree
Isabel Simulation ResultsIsabel Simulation Results
Comparison of Model ResultsComparison of Model Results(with and without inundation)(with and without inundation)
G loucester Point (with flooding)
-0.5
0
0.5
1
1.5
2
2.5
0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72
Hour (from 9/17/2003 0:00)
Ele
vati
on
(m
)
M odeledPredicted (HAM )O bserved
Sewells Point (without flooding)
-0.5
0
0.5
1
1.5
2
0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72
Hour (from 9/17/2003 0:00)
Ele
vati
on
(m
)
M odeledPrediced (HAM )O bserved
Sewells Point (with flooding)
-0.5
0
0.5
1
1.5
2
0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72
Hour (from 9/17/2003 0:00)
Ele
vati
on
(m
)
Modeled
Sweells Hall (HAM)
Observed
Gloucester Point (without flooding)
-0.5
0
0.5
1
1.5
2
2.5
0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72
Hour (from 9/17/2003 0:00)
Ele
vatio
n (m
)
ModeledPredicted (HAM)Observed
Comparison of Model ResultsComparison of Model Results(with and without inundation)(with and without inundation)
Baltimore (with flood)
-0.5
0
0.5
1
1.5
2
2.5
0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72
Hour (from 9/17/2003 0:00)
Ele
vati
on
(m
)
M odeled Prediced (HAM )O bserved
Baltimore (without flood)
-0.5
0
0.5
1
1.5
2
2.5
0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72
Hour (from 9/17/2003 0:00)
Ele
vati
on
(m
)
M odeledPredicted (HAM )O bserved
Colonial Beach (with flood)
-0.5
0
0.5
1
1.5
2
0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72
Hour (from 9/17/2003 0:00)
Ele
vati
on
(m
)
M odeledPredicted (HAM )
Observed
Colonial Beach (without flood)
-0.5
0
0.5
1
1.5
2
2.5
0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72
Hour (from 9/17/2003 0:00)
Ele
vati
on
(m
)
M odeledPredicted (HAM )Observed
Influence of Open Boundary ConditionInfluence of Open Boundary Condition
G loucester Point (with flooding)
-0.5
0
0.5
1
1.5
2
2.5
0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72
Hour (from 9/17/2003 0:00)
Ele
vati
on
(m
)
M odeledM odeled (IPABC)O bserved
Sewells Point (with flooding)
-0.5
0
0.5
1
1.5
2
0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72
Hour (from 9/17/2003 0:00)
Ele
vati
on
(m
)
Modeled
Modeled (IPABC)
Observed
Inverse Pressure Adjustment
Comparison with ADCIRC• UnTrim
– With inverse pressure adjustment
– Timestep =5 minutes
• ADCIRC– Without inverse pressure adjustment
– Timestep =5 sec
Gloucester Point (with flooding)
-0.5
0
0.5
1
1.5
2
2.5
0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72
Hour (from 9/17/2003 0:00)
Ele
vati
on
(m
)
ADCIRC UnTRIM
Observed
Comparison with ADCIRC
Swelles Hall (with flooding)
-0.5
0
0.5
1
1.5
2
0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72
Hour (from 9/17/2003 0:00)
Ele
vati
on
(m
)
ADCIRC UnTRIM
Observed
ConclusionsConclusions
• Grid resolution is crucial for accurately simulating surge and inundation
• Wind filed is critical in accurately simulation storm surge
• Unstructured model is a robust tool for simulating tide and storm surge