warner_ROMS_scripps.ppt by lanyuehua

VIEWS: 208 PAGES: 29

									Incorporating nearshore processes
           into ROMS

        John Warner, USGS
• 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
• Recent advancements
   – Q_PSOURCE           - wetting/drying
   – surface tke flux    - wave/current interactions
   – bedload             - 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
• Advance instrumentation and data analysis techniques for
making measurements to test and improve sediment-transport
• 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,
C05001, doi:10.1029/2004JC002691.

                                                                                along channel

                                                                           Comparisons between
                                                                            model and observed

         Time series at site N3 (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
 C U i C           C         C 
                KH         KV       Sources / Sinks
 t   xi    xi 
                     x1, 2      x3 
                                                                             Bed Model
  Erosion formulation
                                  t b  t ce
     Source  E 0 1                                   when tb > tce
                                     t ce

 Deposition formulation
          Sink  ws

 Bed load transport: Meyer-Peter Muller
               t sf
t *sf 
           s   gD                  non-dimensional shear stress

  8t *sf  0.047
                           3/ 2
                                        non-dimensional sediment flux

             s                       bed load transport rate, kg m-1 s-1
qbl               gD 3
Waves – Currents – Sediment
            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 ANA_PSOURCE (or from NetCDF file)                   rivers

Flux of water imposed at horizontal u or v points.                   X             X

step2d.F:           ubar = Qbar / (dy H); vbar = Qbar / (dx H)
step3d_uv.F:        u = Qsrc / (dy Hz); v = Qsrc / (dx Hz);
step3d_t.F:         FX = Hz u on * Tsrc

additional method:
#define ANA_PSOURCE (or from NetCDF file)
Flux of water imposed in the vertical at rho points.
step2d.F:          zeta = zeta + Qbar *dt / (dx dy)
omega.F:           W = Qsrc
step3d_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.
                                 t k 
                                 z   c w u s
                                       
                                                      3                      c w ~ 100;        *
                                                                                               u s = surface stress
                                k      s
1) #define craig_banner         t ψ    
                                z 
                                         k cμ
                                                          p                            n
                                                                                               
                                                                m k m1 Lsft ( z  z 0 ) c w u s
                                                                                                 *   3
                                                                                                                  c 0     p 1
                                                                                                                                   k m1 / 2 Ln 1 z  z 0 

                                        s y                                                                y
                                                                                                                      μ                       sft
                               y

                                 t k 
2) #define tke_wavediss        
                                 z   a  w
                                                                                  a ~ 0.25               w = wave energy dissipation
                                k      s

                                t ψ    
                                z 
                                         k cμ
                                                          p
                                                                m k m1 Lsft ( z  z 0 ) a  
                                                                                          n              n
                                                                                                             c 
                                                                                                              0     p 1
                                                                                                                           k m1 / 2 Ln 1 z  z 0 

                                        s y                                                        y
                                                                                                              μ                       sft
                               y

  -- How get Zos ?
  #define charnok                       
                               Zos  a u *
                                                 /g             a = 1400

                               Zo s  aH s                      a = 0.5; Hs = significant wave height
  #define zo_hsig
      (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 (m3/s/m of width)
                                         qbx   x g s  1d 3       
                                                                              current dir

                                         qby   y g s  1d 3   
                                                                  0.5       _|_ 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 3D, RMA2 -       velocity set = 0 when D < D crit; '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).
Trim3D -               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 :      let it happen!
   – Drying :        if D|rho pt < Dcrit
                    only allow flux inward.
        ROMS: wetting and drying
1) initial rho_mask establishes permanent land locations
         (rmask = 0 --> will never be "wet")
2) initial free surface draped over all elevations
3) in step2d, after zeta_new calc
   if D|rho pt < Dcrit then rmask_wet = 0.
   calc umask_wet, vmask_wet,
   ubar_new = uber_new * umask * umask_wet (same for v)
4) in step3d_uv, use same wet mask to block u and v.
               Wetting and Drying
        Suisun Bay, Northern San Francisco Bay, CA

    To                                           Sacramento
Golden Gate
  (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 three-
  dimensional currents and surface wave equations. Preprint.

 start w/ momentum eqs.
coordinate transformation
  avg over 'wave period'

                                    resulting 2D eqtns.

                                           resulting 3D eqtns.

                               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
        • McWilliams 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 Mean
                                         (6)             Model coupling
              Model connectivity programs
• Model Coupling Toolkit -
Mathematics and Computer Science Division Argonne National Laboratory
R. Jacob, J. Larson, E. Ong, “M×N Communication and Parallel Interpolation in CCSM Using the Model Coupling
Toolkit”, (Preprint) ANL/MCSP1225-0205, 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 Fortran90 Toolkit for Building Multiphysics
Parallel Coupled Models”, (Preprint) ANL/MCS-P1208-1204, 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      NOAA National Centers for Environmental Prediction
              NSF National Center for Atmospheric Research    NASA Goddard Global Modeling and Assimilation Office
              NASA Goddard Institute for Space Studies        NASA Jet Propulsion Laboratory
              NASA Goddard Land Information Systems project   DOD Naval Research Laboratory
              DOD Air Force Weather Agency                    DOD Army Engineer Research and Development Center
              DOE Los Alamos National Laboratory              DOE Argonne National Laboratory
              University of Michigan                          Princeton University
              Massachusetts Institute of Technology           UCLA
              Center for Ocean-Land-Atmosphere Studies        Programme for Integrated Earth System Modeling (PRISM)
              Common Component Architecture (CCA)
                        Data Transfers using the MCT
 Atm. Model (M nodes)       Coupler (N nodes)              Ocean Model (P nodes)
  Call MCT World            Call MCT World                  Call MCT World

  Define GlobalSegMap       Define GlobalSegMaps            Define GlobalSegMap
  Define AttrVect           Define AttrVects                Define AttrVect
  Define Router             Define Routers                  Define Router
                            Define Accumulators
                            Read Matrix elements
  Read Atmosphere                                           Read Ocean Data

MCT_Send(AtrVect, Router)    MCT_Recv(AAtrVect, ARouter)
                             MCT_Recv(OAtrVect, ORouter)      MCT_Send(AtrVect, Router)

MCT_Recv(AtrVect, Router)   MCT_Send(AAtrVect, ARouter)
                               Synchronization point
                            MCT_Send(OAtrVect, ORouter)       MCT_Recv(AtrVect, Router)
       Current Inter - Model Coupling

                                u, v, h     Hwave

Schaffer/                                   USGS
                  Perlin, OSU
          Interconnection of many modeling components
        ROMS              WRF            COAMPS             SWAN           NEW
        - init            - init         - init             - init         - init
        - run             - run          - run              - run          - run
        - finalize        - finalize     - finalize         - finalize     - finalize



- 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          2

ubar = 0.5 m/s
                                    Hs = 2.0 m   depth (m)
                                     T = 10 s


                   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                          ROMS zeta + u/v

 effect of currents on waves      wave generated currents
(swan uncoupled vs coupled)    (roms uncoupled vs. coupled)
• 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           - provide documentation
  - model coupling               - wave / current interaction

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