Presentation by Firmijn Zijl, Deltares, at the Delft3D - User Days (Day 2: Hydrodynamics), during Delft Software Days - Edition 2019. Tuesday, 12 November 2019, Delft.
Reassessing the Bedrock of Clinical Function Models: An Examination of Large ...
DSD-INT 2019 3D model of the North Sea using Delft3D FM-Zijl
1. D e l t a r e s – D e l f t S o f t w a r e D a y s – 1 2 N o v e m b e r 2 0 1 9
Firmijn Zijl, Julien Groenenboom and Stendert Laan
3D model of the North Sea using Delft3D FM
2. Contents
• Background
• Model setup
• Results
• Ongoing developments
o Current validation
o Extension with Baltic Sea
3DmodeloftheNorthSeausingDelft3DFM
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3. Background - ‘Sea Level Science’
• Models used for official Dutch water level forecasts
• Accurate, real-time water level forecasting important for informed discussion on movable barrier closure
• D-Flow FM module of the Delft3D Flexible Mesh Suite (Delft3D FM) now available
➢ New model to take advantage of new possibilities: DCSM-FM (DCSM = Dutch Continental Shelf Model)
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4. Background – ‘Environmental Hydrodynamics’
Outside world (e.g. CMEMS):
• Increased spatial extent
• Higher horizontal resolution
• Higher vertical resolution
➢Upgrade required
Difference in approach for:
• Environmental Hydrodynamics
(with 3D transport models)
• Sea Level Science
(with 2D tide-surge models)
Solution: borrow schematization, barotropic forcing and
calibration effort from existing 2D models
3D ZUNO(-DD) model
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5. Background – Proposed DCSM-FM schematisations
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DCSM-FM 0.5nm
DCSM-FM 100m
2D
3D (+S/T)
2D
Ensemble Prediction
System (EPS)
Deterministic water level
forecasts
Water levels (incl. MDT)
Geodetic applications
Currents and transport
Water quality and ecology
3D boundary conditions
Oil dispersal
SAR
MetOcean
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6. Model setup – Network and bathymetry
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Yellow: 1/10° x 1/15° ~ 4 nm x 4 nm
Green: 1/20° x 1/30° ~ 2 nm x 2 nm
Blue: 1/40° x 1/60° ~ 1 nm x 1 nm
Red: 0.75’ x 0.5’ ~ 0.5 nm x 0.5 nm
→ 800 m isobath
→ 50 m isobath
→ 200 m isobath
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7. Model setup – Network optimization
• Transitions in resolution (triangles) outside locations with high flow velocities → more cells, but faster
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8. Model setup – Barotropic forcing
Open boundary forcing
• Water level elevation imposed at 205 sections:
• Tide (from FES2012; 33 constituents)
• Storm surge (Inverse Barometer Correction)
Surface forcing
• Wind speed and air pressure from:
• HIRLAM7.2 →Arome-Harmonie
• ERA-Interim →ERA5
• ECMWF IFS
• Charnock relation for sea surface roughness (consistent with
meteo model), except:
• Surface current speed taken into account in wind drag relation
Also included
• Tidal potential
• Energy dissipation through generation of internal waves
• Barrier operations (closing of 8 storm surge barriers)
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9. Model setup – 3D baroclinic model
• 20 equidistant σ-layers (→51 z-layers)
• k-ε turbulence closure model
• Lateral forcing:
• Temperature and salinity from World Ocean Atlas (WOA13)
(As climatological mean monthly fields (0.25° grid, 107 depth levels, steps of 5 m at surface)
• Steric water level contribution
• Heat fluxes computed based on:
• Dew point temperature, air temperature and cloud cover (and wind speed)
• Fresh water discharges (~900):
• Climatology derived from EHYPE
Monthly means derived from 2001-2013
• 7 most important Dutch rivers
• 3 most important German rivers (Ems, Weser, Elbe)
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10. Model setup – Computational times
• Maximum allowed numerical time step increasing from 120s to 200 s
• With the upgraded flexible resolution grid and increased time step, the model is 4 times faster
Model
Resolution
Comp. time
(min/day)*
Comp. time
(hr/yr)*
Avg. time step
(s)
# nodes
DCSMv6 (WAQUA) 1nm 1.6 10.0 120 859,217
DCSM-FM (1nm ) 4nm-1nm 0.4 2.5 199 373,522
DCSM-FM (0.5nm) 4nm-0.5nm 1.2 7.5 118 629,187
3D DCSM-FM (0.5nm) 4nm-0.5nm 13.0 79 111 629,187
*On 20 CPU cores
(3D ZUNO-DD: ~5 days/year)
Possibilities:
• 2D: Ensemble with 50 members
• 3D: Decadal scale 3D computations
• 3D: Real-time forecasting computations
Combining 2D/3D in one schematization is feasible:
• more resolution,
• much larger domain,
• more vertical resolution
• less computational cost!
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12. Model results – Surface salinity and temperature
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Salinity Temperature
13. Model results – Surface salinity and temperature
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Salinity Temperature
14. Model results – Temperature (stratification)
Measurement
Simulation
Stratification (surface minus bottom)
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Sea Surface Temperature
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15. Model results – Current velocity (2D vs. 3D)
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3D (surface)2D
16. Model results – Current velocity (2D vs. 3D)
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2D 3D (surface)
18. Baltic Sea – Network and bathymetry
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Green: 1/20° x 1/30° ~ 2 nm x 2 nm
Blue: 1/40° x 1/60° ~ 1 nm x 1 nm
Red: 0.75’ x 0.5’ ~ 0.5 nm x 0.5 nm
→ 100 m isobath
→ 50 m isobath
19. Baltic Sea – Salinity and temperature (preliminary)
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Salinity Temperature
20. Baltic Sea – Salinity and temperature (preliminary)
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TemperatureSalinity
21. Baltic Sea – Water levels
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22. Baltic Sea – Water levels (impact on DCSM-FM)
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No significant impact on water levels in Skagerrak/Kattegat
DCSM-FM + Baltic DCSM-FM only
23. Baltic Sea – Salinity in 3D DCSM-FM
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23/25DCSM-FM only
24. Baltic Sea – Salinity (exchange with Kattegat)
• Impact on salinity
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25. Baltic Sea – Salinity (exchange with Kattegat)
• Impact on salinity
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26. D e l t a r e s – D e l f t S o f t w a r e D a y s – 1 2 N o v e m b e r 2 0 1 9
Firmijn Zijl, Julien Groenenboom and Stendert Laan
3D model of the North Sea using Delft3D FM