Custom Query (964 matches)

Corrected CPP logic in get_idata.F during the processing of AVERAGES_DETIDE. See the following ROMS forum ​posting for details. Many thanks to J.Paul Rinehimer for reporting this problem.

Corrected a small parallel bug when reporting the waiting time during coupling synchonization. Notice that the couple interface using the MCT libary has calls like:

      buffer(1)=my_wtime(wtime)
      CALL MCT_Recv (wav2ocn_AV, ROMStoSWAN, MyError)
      RecvTime=RecvTime+my_wtime(wtime)-buffer(1)
      ...
      buffer(2)=my_wtime(wtime)
      CALL MCT_Send (ocn2wav_AV, ROMStoSWAN, MyError)
      SendTime=SendTime+my_wtime(wtime)-buffer(2)

in all coupled models drivers. For example, see mct_roms_swan.h. Several statistics are reported to standard output to check the parallel/communication balance between all models. For the INLET_TEST example that couples ROMS and SWAN, we get:

NL ROMS/TOMS: started time-stepping: (Grid: 01 TimeSteps: 00000001 - 00005760)

   STEP   Day HH:MM:SS  KINETIC_ENRG   POTEN_ENRG    TOTAL_ENRG    NET_VOLUME

      0     0 00:00:00  0.000000E+00  4.346400E+01  4.346400E+01  1.444800E+09
      DEF_HIS   - creating history file: ocean_his.nc
      WRT_HIS   - wrote history  fields (Index=1,1) into time record = 0000001
      1     0 00:00:30  4.136166E-09  4.346401E+01  4.346401E+01  1.444800E+09
      2     0 00:01:00  8.618362E-08  4.346321E+01  4.346321E+01  1.444789E+09
      3     0 00:01:30  7.147723E-07  4.346093E+01  4.346093E+01  1.444757E+09
      4     0 00:02:00  2.555187E-06  4.345713E+01  4.345713E+01  1.444702E+09
      WAV2OCN   - (04) imported and (07) exported fields,    t = 20000101.000200
                - SWAN coupling exchanges wait clock (s):
                   (Recv= 3.07452679E-02 Send= 9.13143158E-04)
      OCN2WAV   - (07) imported and (04) exported fields,    t =     0 00:02:00
                - ROMS coupling exchanges wait clock (s):
                   (Recv= 1.21391559E+01 Send= 9.74893570E-04)
                - ROMS Import: wave energy dissipation
                   (Min=  0.00000000E+00 Max=  1.72405359E-04)
                - ROMS Import: significant wave height
                   (Min=  0.00000000E+00 Max=  9.97979820E-01)
                - ROMS Import: surface wave relative peak period
                   (Min=  0.00000000E+00 Max=  9.51826859E+00)
                - ROMS Import: bottom wave period
                   (Min=  0.00000000E+00 Max=  1.06277828E+01)
                - ROMS Import: wave bottom orbital velocity
                   (Min=  0.00000000E+00 Max=  2.00194478E-01)
                - ROMS Import: wave direction
                   (Min=  0.00000000E+00 Max=  6.28318477E+00)
                - ROMS Import: average wave length
                   (Min=  0.00000000E+00 Max=  9.23759995E+01)
                - ROMS Export: bathymetry
                   (Min=  4.00000000E+00 Max=  1.55200000E+01)
                - ROMS Export: free-surface
                   (Min= -1.21127734E-02 Max=  8.22481532E-06)
                - ROMS Export: vertically integrated u-momentum component
                   (Min= -1.15870464E-05 Max=  1.15870464E-05)
                - ROMS Export: vertically integrated v-momentum component
                   (Min= -5.86567341E-06 Max=  8.49970348E-03)
      5     0 00:02:30  8.630084E-06  4.345318E+01  4.345319E+01  1.444644E+09

Here, the time-step for ROMS is dt=30 s and SWAN has d=60 s. The coupling between the two models is every 120 s. ROMS is run on 1 cpu whereas SWAN is run on 2 cpus. Notice that the time-step in ROMS is half of the one specified in SWAN. However, ROMS can be run at much larger time-step. The CFL condition for this case is around 10 s for the barotropic time-step (to resolve gravity waves) which implies a baroclinic time-step, dt=10*NDTFAST. If NDTFAST=20, dt=200.

According to the above numbers, SWAN is a much expensier model than ROMS for the same grid. Notice that the value Recv= 1.21391559E+01 s measures the time that ROMS is waiting for SWAN to arrive to the MCT (MPI) synchronization point. ROMS arrived much earlier even though is running at half of the time-step of SWAN and on just 1 cpu. This implies that we need to assign more parallel nodes to SWAN to balance the coupling computation.

This is a nice information to have so the computational resources can be allocated in an efficient way for a particular application.

I added a sanity check in the advection options for momentum and tracers in checkdefs.F. The model now will stop if the user defines more than one horizontal and vertical advection for momentum or tracers. Because of the way that advection is coded, the order of these options is important in the predictor and corrector algorithms. If you specify more than one option you will get a different behavior.

Many thanks to John Wilkin for pointing out this potential problem. Recall, that ROMS writes a lot of information to standard output. The users should pay a lot attention to the information that is written.