Incorporating nearshore processes into ROMS John Warner USGS

Incorporating nearshore processes into ROMS John Warner, USGS

Outline • USGS Participation – Role of USGS • Overview of some contributions to the model (mostly driven by our needs in regional apps) – Turbulence closures (GLS) – Sediment transport – MPDATA • Recent advancements – Q_PSOURCE – surface tke flux – bedload - wetting/drying - wave/current interactions - model coupling • Summary /where are we going?

Role of Coastal & Marine Geology We provide scientific information to • • Describe and understand the earth Minimize losses from natural disasters Manage resources Enhance / protect quality of life N. Myrtle Beach-March 1993 Need numerical models for: • Study basic science processes • Regional projects (Mass Bay, South Carolina, Adriatic, …) • Prediction (shoreline change, coastal evolution, aggregate resources, restoration, natural disasters)

Community Sediment Transport Modeling Program Chris Sherwood, Rich Signell, John Warner, Brad Butman • Promote/test/select/develop/adopt/improve/maintain community models • Advance instrumentation and data analysis techniques for making measurements to test and improve sediment-transport models. • Advance software analysis and visualization tools that support model applications. • Apply sediment transport models to benefit regional studies (South Carolina, North Carolina, Mass Bay, Adriatic, Hudson River, . . . )

Some of our recent contributions to ROMS 1) Turbulence closures (GLS) Warner, J. C. , Sherwood, C. R. , Arango, H. G. , and Signell, R. P. (2005) “Performance of four turbulence closure models implemented using a generic length scale method. ” Ocean Modelling 8, p. 81 -113. Warner, J. C. , W. R. Geyer, and J. A. Lerczak (2005), Numerical modeling of an estuary: A comprehensive skill assessment, J. Geophys. Res. , 110, C 05001, doi: 10. 1029/2004 JC 002691. along channel Comparisons between model and observed salinity Time series at site N 3 (river km 22).

recent contribs (cont'd) 2) Surface tke flux due to wave breaking 3) Isobaric drifters (constant z or constant depth) 4) Monotonic advection scheme (MPDATA) 5) Suspended sediment and bed load transport Warner, J. C. , Sherwood, C. R. , Signell, R. P. , Butman, B. , Arango, H. G. , Shchepetkin, A. , nad Blaas, M. (in prep. ) Community Sediment Transport Model User’s Guide, Version 1. 0, USGS Open File Report No. XXXX. 6) Bed framework + transport of multiple sediment classes 7) Wave/current bottom boundary layer interactions

Sediment transport components Suspended sediment transport Bed Model Erosion formulation when tb > tce Deposition formulation Bed load transport: Meyer-Peter Muller non-dimensional shear stress non-dimensional sediment flux bed load transport rate, kg m -1 s-1

Waves – Currents – Sediment Interaction

Deposited Suspended Process studies: point mass releases

Incorporating a few nearshore processes 1) Rho point sources (#define Q_PSOURCE) 2) Surface tke fluxes (zo_hsig, tke_wavediss charnok, craig_banner) 3) Sediment bedload transport 4) Wetting and drying 5) Wave/current interactions 6) Model coupling

(1) Rho point sources existing formulation: #define UV_PSOURCE, TS_PSOURCE #define ANA_PSOURCE (or from Net. CDF file) Flux of water imposed at horizontal u or v points. step 2 d. F: step 3 d_uv. F: step 3 d_t. F: rivers X X ubar = Qbar / (dy H); vbar = Qbar / (dx H) u = Qsrc / (dy Hz); v = Qsrc / (dx Hz); FX = Hz u on * Tsrc additional method: #define Q_PSOURCE, TS_PSOURCE #define ANA_PSOURCE (or from Net. CDF file) Flux of water imposed in the vertical at rho points. step 2 d. F: zeta = zeta + Qbar *dt / (dx dy) omega. F: W = Qsrc step 3 d_t. F: FC = Qsrc * t diffusers, river mass, GW, precip

(2) Surface tke fluxes Two formulations to account for surface injection of tke due to breaking waves. For GLS each formulation requires boundary conditions for k and y. ~ 100; = surface stress 1) #define craig_banner 2) #define tke_wavediss -- How get Zos ? #define charnok #define zo_hsig a ~ 0. 25 = wave energy dissipation a = 1400 a = 0. 5; Hs = significant wave height

(3) Sediment bedload formulation Bedload transport due to combined waves + currents Soulsby, R. L. , and Damgaard, J. S. 2005. Bedload transport in coastal waters. Coastal Engineering, 52, p. 673 -689. Bedload flux (m 3/s/m of width) current dir _|_ to current dir

(4) Wetting and Drying Why is it a problem? (reminder: D = h + h > 0) - non-negative grid cell thickness (log layer) - D ~= 0! Conservancy properties of model divides by D. - Wave number calculations [sqrt (gh)] Formulation in other models: Typical implementation is flux blocking at velocity points. DELFT 3 D, RMA 2 - velocity set = 0 when D < Dcrit; 'rewet' for D > 2*Dcrit. possibility of strong gradients -> oscillations GETM - factor multiplier in momentum eqts. , shallow water balance (g dh/dx ~ Cd u |V|/D) does not guarantee D >0 (needs other criteria). Trim 3 D implicit formulation, flux blocking on next dt. POM WAD set u/v = 0 when D|vel pt < Dcrit

ROMS: wetting and drying • Our approach (maybe consistent with EFDC (? )) • Special form of "cell face blocking" • Divide problem into 2 processes: – Wetting : – Drying : let it happen! if D|rho pt < Dcrit only allow flux inward.

ROMS: wetting and drying Methodology: 1) initial rho_mask establishes permanent land locations (rmask = 0 --> will never be "wet") 2) initial free surface draped over all elevations 3) in step 2 d, after zeta_new calc if D|rho pt < Dcrit then rmask_wet = 0. calc umask_wet, vmask_wet, ubar_new = uber_new * umask_wet (same for v) 4) in step 3 d_uv, use same wet mask to block u and v.

Wetting and Drying Suisun Bay, Northern San Francisco Bay, CA To Golden Gate To Sacramento

(5) Wave current interactions - Wind generated waves. - Waves shoal and refract. - Waves propagating into the coastal zone can generate significant nearshore currents. - Waves nonlinearly interact with these currents and currents generated from other processes (such as tides).

Radiation Stress Method -Mellor, G. L. 2003 The three-dimensional current and surface wave equations. Journal of Physical Oceanography 33, 1978 -1989. - Mellor, G. L. 2004 Some consequences of the threedimensional currents and surface wave equations. Preprint. start w/ momentum eqs. coordinate transformation avg over 'wave period' resulting 2 D eqtns. resulting 3 D eqtns. needs: Hwave, Lwave, Dwave

Test case w/ radiation stress method Hs = 2. 0 m T = 10 s

but is it correct ? ? Recent Habilitation by Fabrice Ardhuin - attempts to reconcile 3 approaches of: • Mellor radiation stress method • Mc. Williams et al vortek force method • Generalized Lagrangian Mean method - suggests that Mellor left out a few terms that are of same order as leading terms - suggests an inconsistency in the vortex force formulations surface boundary condition - suggests that GLM provides a more consistent framework that covers entire water column.

Generalized Lagrangian Method

(6) Model coupling Model connectivity programs • Model Coupling Toolkit Mathematics and Computer Science Division Argonne National Laboratory http: //www-unix. mcs. anl. gov/mct/ R. Jacob, J. Larson, E. Ong, “M×N Communication and Parallel Interpolation in CCSM Using the Model Coupling Toolkit”, (Preprint) ANL/MCSP 1225 -0205, Mathematics and Computer Science Division, Argonne National Laboratory, Feb 2005. Submitted to International Journal for High Performance Computing Applications. J. Larson, R. Jacob, E. Ong, “The Model Coupling Toolkit: A New Fortran 90 Toolkit for Building Multiphysics Parallel Coupled Models”, (Preprint) ANL/MCS-P 1208 -1204, Mathematics and Computer Science Division, Argonne National Laboratory, Dec 2004. Submitted to International Journal for High Performance Computing Applications. • Earth System Modeling Framework http: //www. esmf. ucar. edu/ "The ESMF defines an architecture for composing multi-component applications and includes data structures and utilities for developing model components. " Partners: NOAA Geophysical Fluid Dynamics Laboratory NSF National Center for Atmospheric Research NASA Goddard Institute for Space Studies NASA Goddard Land Information Systems project DOD Air Force Weather Agency DOE Los Alamos National Laboratory University of Michigan Massachusetts Institute of Technology Center for Ocean-Land-Atmosphere Studies Common Component Architecture (CCA) NOAA National Centers for Environmental Prediction NASA Goddard Global Modeling and Assimilation Office NASA Jet Propulsion Laboratory DOD Naval Research Laboratory DOD Army Engineer Research and Development Center DOE Argonne National Laboratory Princeton University UCLA Programme for Integrated Earth System Modeling (PRISM)

Data Transfers using the MCT Atm. Model (M nodes) Coupler (N nodes) Ocean Model (P nodes) Call MCT World Define Global. Seg. Map Define Attr. Vect Define Router Define Global. Seg. Maps Define Attr. Vects Define Routers Define Accumulators Read Matrix elements Define Global. Seg. Map Define Attr. Vect Define Router Read Atmosphere Data MCT_Send(Atr. Vect, Router) MCT_Recv(Atr. Vect, Router) Initialization Read Ocean Data MCT_Recv(AAtr. Vect, ARouter) MCT_Recv(OAtr. Vect, ORouter) Interpolate MCT_Send(AAtr. Vect, ARouter) Synchronization point MCT_Send(OAtr. Vect, ORouter) MCT_Send(Atr. Vect, Router) MCT_Recv(Atr. Vect, Router)

Current Inter - Model Coupling u, v, h Schaffer/ Arango Dwave, Hwave Lwave, Pwave_top, Pwave_bot, Ub_swan Wave_dissip USGS Perlin, OSU

Interconnection of many modeling components master. F ROMS - init - run - finalize WRF - init - run - finalize COAMPS - init - run - finalize SWAN - init - run - finalize NEW - init - run - finalize Coupler New model - Allow many different and new models to communicate using a common data transfer strucutre. - MCT is really the network architecture that allows inter-model communications and contains

Inlet Test 1200 m ubar = 0. 5 m/s Hs = 2. 0 m T = 10 s 2 depth (m) 16 1200 m 4 cases: 1) SWAN uncoupled 2) ROMS uncoupled without rad stress terms 3) ROMS uncoupled with rad stress terms and SWAN forcing (from 1) 4) ROMS + SWAN coupled

Inlet test results SWAN Hs effect of currents on waves (swan uncoupled vs coupled) ROMS zeta + u/v wave generated currents (roms uncoupled vs. coupled)

Summary • Inocorporated processes for 1) Rho point sources (#define Q_PSOURCE) 2) Surface tke fluxes ( zo_hsig, tke_wavediss charnok, craig_banner) 3) Sediment bedload transport 4) Wetting and drying 5) Wave/current interactions 6) Model coupling • Future directions: - turn on morphology - model coupling - provide documentation - wave / current interaction