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Step-by-step use of OASIS 3.0

Step-by-step use of OASIS 3.0. Sophie Valcke PRISM Workshop KOWI, Brussels February 26-27, 2003. Step-by-step use of OASIS 3.0. With special thanks to: Arnaud Caubel (Fujitsu-fecit) Reiner Vogelsang (Silicon Graphics GmbH) Veronika Gayler (MPI, M&D) Damien Declat (CERFACS).

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Step-by-step use of OASIS 3.0

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  1. Step-by-step use of OASIS 3.0 Sophie Valcke PRISM Workshop KOWI, Brussels February 26-27, 2003

  2. Step-by-step use of OASIS 3.0 With special thanks to: Arnaud Caubel (Fujitsu-fecit) Reiner Vogelsang (Silicon Graphics GmbH) Veronika Gayler (MPI, M&D) Damien Declat (CERFACS)

  3. Step-by-step use of OASIS 3.0Outline 1. Historic, overview, community 2. Model interfacing: PSMILe V.0 3. Sequence and lag concepts - Coupling algorithms 4. Oasis configuration file namcouple • Key notes • General parameters • I/O-coupling field general description • Field transformations 5. Auxiliary data files (grids, restarts, transformations) 6. Conclusions and perspectives

  4. Step-by-step use of OASIS 3.01. Historic, overview, community 1.1 Historic 1.2 Overview 1.3 Community

  5. Step-by-step use of OASIS 3.01. Historic, overview, community 1.1 Historic 1991: Need analysis 1993: Oasis 1.0: Pipe CRAY and ASCII files 1995: Oasis 2.0: Global rewriting + CLIM/PVM3 1996: Oasis 2.1: Used for 100-year climate change simulation 1998: Oasis 2.2: SVIPC communication 1999: Oasis 2.3: GMEM (NEC) communication 2000: Oasis 2.4: MPI2 communication 2002: Oasis 2.4.1: MPI1 communication 2003: Oasis 3.0: PRISM System Model Interface Library

  6. Step-by-step use of OASIS 3.01. Historic, overview, community O A O A OASIS O A O Static coupling: all coupling parameters are fixed initially by the user in an input file namcouple 1.2 Overview • 1 monoprocess coupler: • synchronisation of component models • exchange of coupling fields • interpolation of coupling fields • Sequential or concurrent coupling • Arbitrary number of (parallel) models and coupling fields • Different coupling frequencies for the different fields • Particular transformations for each field

  7. Step-by-step use of OASIS 3.01. Historic, overview, community 1.3 Community Regular users: • CERFACS • METEO-FRANCE (France) • IPSL- LODYC, LMD, LSCE (France) • ECMWF (UK) • UCL (Belgium) • MPI - M&D (Germany) • SMHI (Sweden) • BMRC (Australia) • IRI (USA) • …and : • AWI (Germany) • PIK (Germany) • Met Office (UK) • UGAMP (UK) • KNMI (Netherlands) • CSIRO (Australia) • FSU/COAPS (USA) • LASG (China) • JAMSTEC (Japan) • …?

  8. Step-by-step use of OASIS 3.02. Model interfacing: PSMILe V.0 2.1 Initialisation 2.2 Partition definition (5) 2.3 I/O-coupling field declaration (3) 2.4 End of definition phase 2.5 I/O-coupling field sending (2) 2.6 I/O-coupling field reception 2.7 Termination

  9. Step-by-step use of OASIS 3.02. Model interfacing: PSMILe V.0 2.1 Initialisation All processes initialise the coupling and retrieve a local communicator for internal parallelisation • USE mod_prism_proto • CALL prism_init_comp_proto (compid, model_name, ierror) • compid [INTEGER; OUT]: component model ID. • model_name [CHARACTER*6; IN]: name of calling model. • ierror [INTEGER; OUT]: error code. If model calls MPI_Init, it must be before calling prism_init_comp_proto • CALL prism_get_localcomm_proto (local_comm, ierror ): • local_comm [INTEGER; OUT]: local communicator. • ierror [INTEGER; OUT]: error code.

  10. Step-by-step use of OASIS 3.02. Model interfacing: PSMILe V.0 2.2 Partition definition (1/5) Each process implied in the coupling defines its local partition in the global index space. • CALL prism_def_partition_proto (il_part_id, ig_paral, ierror): • il_part_id [INTEGER; OUT]: partition ID. • ig_paral [INTEGER, DIMENSION(:), IN]: vector of integers describing the local partition in the global index space. • ierror [INTEGER; OUT]: error code.

  11. Step-by-step use of OASIS 3.02. Model interfacing: PSMILe V.0 2.2 Partition definition (2/5) • CALL prism_def_partition_proto (…, ig_paral, …): * Monoprocess model: • ig_paral(1) = 0 • ig_paral(2) = 0 • ig_paral(3) = total grid size See oasis/toymodel/toyclim/Oce/Src/oce.F90

  12. Step-by-step use of OASIS 3.02. Model interfacing: PSMILe V.0 2.2 Partition definition (3/5) • CALL prism_def_partition_proto (…, ig_paral, …): * Parallel model with APPLE decomposition: • ig_paral(1) = 1 • ig_paral(2) = local offset • ig_paral(3) = local partition size See oasis/toymodel/toyclim/Atm/Src/decomp_def.F90 Proc 2: local offset = 4 local size = 6 Proc 1: local offset = 0 local size = 4 Proc 3: local offset = 10 local size = 5

  13. Step-by-step use of OASIS 3.02. Model interfacing: PSMILe V.0 2.2 Partition definition (4/5) • CALL prism_def_partition_proto (…, ig_paral, …): * Parallel model with BOX decomposition: ig_paral(1) = 2 ig_paral(4) = local y extent ig_paral(2) = local offset ig_paral(5) = global x extent ig_paral(3) = local x extent See oasis/toymodel/toyclim/Atm/Src/decomp_def.F90 global x extent = 5 Proc 2: local offset = 2 local x extent = 3 local y extent = 2 Proc 1: local offset = 0 local x extent = 2 local y extent = 2 Proc 3: local offset = 10 local x extent = 5 local y extent = 1

  14. Step-by-step use of OASIS 3.02. Model interfacing: PSMILe V.0 2.2 Partition definition (5/5) • CALL prism_def_partition_proto (…, ig_paral, …): * Parallel model with ORANGE decomposition: ig_paral(1) = 3 ig_paral(5) = 2nd segment offset ig_paral(2) = nbr of segments ig_paral(6) = 2nd segment size ig_paral(3) = 1st segment offset … ig_paral(4) = 1st segment size See oasis/toymodel/toyclim/Atm/Src/decomp_def.F90 Proc 1: 1st segment offset = 0 nbr of segments = 3 1st segment size = 4 2nd segment offset = 7 2nd segment size = 2 3rd segment offset = 10 3rd segment size = 3

  15. Step-by-step use of OASIS 3.02. Model interfacing: PSMILe V.0 2.3 I/O-coupling field declaration (1/3) Each process implied in the coupling declares the fields it will send or receive during the simulation • CALL prism_def_var_proto(var_id, name, il_part_id, var_nodims, kinout, …) • var_in [INTEGER; OUT]: coupling field ID • Name [CHARACTER*8; IN]: field symbolic name • il_part_id [INTEGER; IN]: partition ID • var_nodims [INTEGER, DIMENSION(2); IN]: • var_nodims(1): rank of field array (1 or 2). • var_nodims(2): number of bundles (always 1, not used for now). • kinout [INTEGER; IN]:'PRISM_In', or 'PRISM_Out'. …

  16. Step-by-step use of OASIS 3.02. Model interfacing: PSMILe V.0 2.3 I/O-coupling field declaration (2/3) • CALL prism_def_var_proto(…, var_actual_shape, var_type, ierror) … • var_actual_shape [INTEGER, DIMENSION (:); IN]: minimum and maximum index for each field array dimension (i.e. 1 and dimension extent) • var_type [INTEGER; IN]: type of coupling field array,‘PRISM_Real’ or ‘PRISM_Double’ • ierror [INTEGER; OUT]: error code.

  17. Step-by-step use of OASIS 3.02. Model interfacing: PSMILe V.0 2.3 I/O-coupling field declaration (3/3) • CALL prism_def_var_proto(…, var_type, …) Recommendation (PRISM coding rules): • USE mod_kinds_model • REAL(kind=ip_realwp_p), dimension(:) :: field_array • CALL prism_def_var_proto(…, ‘PRISM_Real’, …) • By default, ip_realwp_p = kind(SELECTED_REAL_KIND(12,307)) . • With cpp key use_realtype_single, ip_realwp_p = kind(SELECTED_REAL_KIND(6,37)) .

  18. Step-by-step use of OASIS 3.02. Model interfacing: PSMILe V.0 2.4 End of definition phase Each process implied in the coupling closes the definition phase • CALL prism_enddef_proto(ierror) • ierror [INTEGER; OUT]: error code

  19. Step-by-step use of OASIS 3.02. Model interfacing: PSMILe V.0 2.5 I/O-coupling field sending (1/2) In the model time stepping loop, each process implied in the coupling sends its part of the I/O-coupling field • USE mod_ prism_put_proto • CALL prism_put_proto(var_id, date, field_array, ierror) • var_id [INTEGER; IN]: coupling field ID (prism_def_var_proto) • date [INTEGER; IN]: number of seconds in the run at the beginning of the timestep (not final PSMILe date format) • field_array [REAL, IN] : I/O-coupling field array • ierror [INTEGER; OUT]: returned error code.

  20. Step-by-step use of OASIS 3.02. Model interfacing: PSMILe V.0 2.5 I/O-coupling field sending (2/2) • CALL prism_put_proto(var_id, date, field_array, ierror) • May be called at each model timestep; 'date' automatically analysed and sending performed only at appropriate time, given the user-defined period in namcouple. • User-defined local time transformation indicated in namcouple (INSTANT, AVERAGE, ACCUMUL, T_MIN or T_MAX) automatically performed and resulting field sent at appropriate time. • Coupling restart file automatically written by last prism_put_proto called in the run.

  21. Step-by-step use of OASIS 3.02. Model interfacing: PSMILe V.0 2.6 I/O-coupling field reception In the model time stepping loop, each process implied in the coupling receivess its part of the I/O-coupling field • USE mod_ prism_get_proto • CALL prism_get_proto(var_id, date, field_array, ierror) • var_id [INTEGER; IN]: coupling field ID (prism_def_var_proto) • date [INTEGER; IN]: number of seconds in the run at the beginning of the timestep (not final PSMILe date format) • field_array [REAL, OUT] : I/O-coupling field array • ierror [INTEGER; OUT]: returned error code. May be called at each model timestep; 'date' automatically analysed and reception performed only at appropriate times, given the user-defined period in namcouple.

  22. Step-by-step use of OASIS 3.02. Model interfacing: PSMILe V.0 2.7 Termination • CALL prism_terminate_proto(ierror) • ierror [INTEGER; OUT]: returned error code. If model called MPI_Init, the model must also call MPI_Finalize, but only after calling prism_terminate_proto.

  23. Step-by-step use of OASIS 3.03. Sequence and lag concepts - Coupling algorithms 3.1 Lag concept 3.2 Sequence concept 3.3 Mix of sequence and lag

  24. Step-by-step use of OASIS 3.03. Sequence and lag concepts - Coupling algorithms writing to or reading from restart files sending or reception activated sending or reception not activated To prevent deadlocks, F1 and F2 produced at previous timestep are used 3.1 Lag concept – 1st example Timestep = 8 Cpl period(F1) = 24 Cpl period(F2) = 24 Lag(F1) = 8 Lag(F2) = 8

  25. Step-by-step use of OASIS 3.03. Sequence and lag concepts - Coupling algorithms 3.1 Lag concept – 2nd example Timestep = 8 Cpl period(F1) = 24 Lag(F1) = 0 Cpl period(F2) = 24 Lag(F2) = 8 Cpl period(F3) = 24 Lag(F3) = 8 To prevent deadlocks, F2 and F3 produced at previous timestep are used

  26. Step-by-step use of OASIS 3.03. Sequence and lag concepts - Coupling algorithms 3.2 Sequence concept – 1st example Timestep = 8 Cpl period(F1) = 24 Seq(F1) = 1 Lag(F1) = 0 Cpl period(F2) = 24 Seq(F2) = 2 Lag(F2) = 0 Cpl period(F2) = 24 Seq(F3) = 3 Lag(F2) = 0 Cpl period(F2) = 24Seq(F4) = 4 Lag(F2) = 0

  27. Step-by-step use of OASIS 3.03. Sequence and lag concepts - Coupling algorithms 3.3 Mix of sequence and lag – sequential model example Timestep = 8 Cpl period(F1) = 24 Seq(F1)=1 Lag(F1) = 8 Cpl period(F2) = 24 Seq(F2)=2 Lag(F2) = -16

  28. Step-by-step use of OASIS 3.04.Oasis configuration file namcouple 4.1 Key notes on namcouple 4.2 Namcouple : general parameters (3) 4.3 Namcouple: I/O-coupling field general description (8) 4.4 Namcouple: field transformations (10)

  29. Step-by-step use of OASIS 3.04.Oasis configuration file namcouple 4.1 Key notes on namcouple • Text file containing all user’s defined information configuring the coupled run. • First section describes general coupling parameters and process management information • Second section describes the coupling fields, their coupling period, and the user’s defined transformations/interpolations • Number of blanks between two character strings non-significant • Lines beginning with # considered as comments • Blank lines not allowed !!!

  30. Step-by-step use of OASIS 3.04.Oasis configuration file namcouple 4.2 Namcouple : general parameters (1/3) • $SEQMODE # Maximum number of fields that have to be, at one particular # coupling time, exchanged sequentially in a given order. 1 • $CHANNEL # Communication technique (MPI1, MPI2, NONE, SIPC, GMEM). # For MPI1 and MPI2, one additional line per model giving the total number # of processes, the number of processes implied in the coupling, # and possibly launching arguments (MPI2). MPI2 3 1 arg1 1 1 arg2 • 1 arg3 • $NFIELDS # Total number of fields described in namcouple 10

  31. Step-by-step use of OASIS 3.04.Oasis configuration file namcouple 4.2 Namcouple: general parameters (2/3) • $JOBNAME # Acronym for the run. RUN • $NBMODEL # Number of models running + their symbolic names (6 characters) 3 toyatm toyoce toyche • $RUNTIME # Total duration of run in seconds 518400 • $INIDATE # Initial date of run (YYYYMMDD) 00010101

  32. Step-by-step use of OASIS 3.04.Oasis configuration file namcouple 4.2 Namcouple: general parameters (3/3) • $MODINFO # Indicates if a header is included with the fields in the binary restart files, # (and with the exchanged fields for PIPE, SIPC and GMEM): YES or NO. NO • $NLOGPRT # Verbose level in Oasis log file cplout: 0,1, or 2. 2 • $CALTYPE # Calendar type : 0 = 365 day calendar (no leap years) # 1 = leap year calendar # n (>1) = n day month calendar 1 • $STRINGS # Begins the I/O-coupling field section

  33. Step-by-step use of OASIS 3.04.Oasis configuration file namcouple 4.3 Namcouple: I/O-coupling field general description (1/8) 4.3.1 EXPORTED and AUXILARY fields (MPI1,MPI2, NONE, SIPC,GMEM) (1/3) The field is received, treated by Oasis: for EXPORTED, it is sent to target model; for AUXILARY, it is combined to an other field. • SOSSTSST SISUTESU 1 86400 5 fldo1.nc out01.nc EXPORTED • 182 152 96 48 topa at31 LAG=+14400 SEQ=+1 • P 2 P 0 # SOSSTSST: Name in source model prism_def_var_proto – 8 characters max # SISUTESU: Name in target model prism_def_var_proto – 8 characters max # 1: Oasis internal label (see driver/src/inipar.f) # 86400: coupling period (in seconds) # 5: Number of transformations performed by (PSMILe and) Oasis

  34. Step-by-step use of OASIS 3.04.Oasis configuration file namcouple 4.3 Namcouple: I/O-coupling field general description (2/8) 4.3.1 EXPORTED and AUXILARY fields (MPI1,MPI2, NONE, SIPC,GMEM) (2/3) • SOSSTSST SISUTESU 1 86400 5 fldo1.nc out01.nc EXPORTED • 182 152 96 48 topa at31 LAG=+14400 SEQ=+1 • P 2 P 0 # ... # fldo1.nc: Coupling restart file – 8 characters max # binary or NetCDF format –> all restart files for one run must be of same type # out01.nc: Output file (needed for NONE only) # EXPORTED: Field status (EXPORTED or AUXILARY) # 182 152: X and Y dimensions of source grid (optional if restart file is NetCDF) # 96 48: X and Y dimensions of target grid (optional if restart file is NetCDF) # topa at31: source & target grid prefix (4 characters; used in grid auxiliary files)

  35. Step-by-step use of OASIS 3.04.Oasis configuration file namcouple 4.3 Namcouple: I/O-coupling field general description (3/8) 4.3.1 EXPORTED and AUXILARY fields (MPI1,MPI2, NONE, SIPC,GMEM) (3/3) • SOSSTSST SISUTESU 1 86400 5 fldo1.nc EXPORTED • 182 152 96 48 topa at31 LAG=+14400 SEQ=+1 • P 2 P 0 # … # LAG=+14400: the number of seconds to add to a prism_put_proto date to equal # the date of a prism_get_proto that should be matched (see 3.1) –optional # SEQ=+1: position of the field in the sequence of exchange at one particular # coupling time (see 3.2) -required only if $SEQMODE > 1 # P 2 P 0: source and target grid type (P for periodical, R for regional) and # number of overlapping grid points in X

  36. Step-by-step use of OASIS 3.04.Oasis configuration file namcouple 4.3 Namcouple: I/O-coupling field general description (4/8) 4.3.2 EXPOUT fields (MPI1,MPI2 only – PSMILe V.0) The field is treated as an EXPORTED field. It is also written at each coupling period to two output files: one by the source model PSMILe below the prism_put_proto, and one by the target model PSMILe below the prism_get_proto • SOSSTSST SISUTESU 1 86400 5 fldo1.nc EXPOUT • 182 152 96 48 topa at31 LAG=+14400 SEQ=+1 • P 2 P 0 # Descriptive lines as for EXPORTED field.

  37. Step-by-step use of OASIS 3.04.Oasis configuration file namcouple 4.3 Namcouple: I/O-coupling field general description (5/8) 4.3.3 IGNORED or IGNOUT fields (MPI1,MPI2 only – PSMILe V.0) (1/2) The field is exchanged directly by the PSMILe between two models having the same grid and the same partitioning. For IGNOUT, the field is also written at each coupling period to two output files: one by the source model PSMILe below the prism_put_proto, and one by the target model PSMILe below the prism_get_proto • COSENHFL SOSENHFL 37 86400 1 flda3.nc IGNORED • LAG=+3600 SEQ=+1 # COSENHFL: Name in source model prism_def_var_proto – 8 characters max # SOSENHFL: Name in target model prism_def_var_proto – 8 characters max # 37: Oasis internal label (see driver/src/inipar.f)

  38. Step-by-step use of OASIS 3.04.Oasis configuration file namcouple 4.3 Namcouple: I/O-coupling field general description (6/8) 4.3.3 IGNORED or IGNOUT fields (MPI1,MPI2 only – PSMILe V.0) (2/2) • COSENHFL SOSENHFL 37 86400 1 flda3.nc IGNORED • LAG=+3600 SEQ=+1 # 86400: Coupling period (in seconds). # 1: Number of transformations performed by PSMILe (0, or 1 –>LOCTRANS) # flda3.nc: Coupling restart file (binary or NetCDF) - 8 characters max # IGNORED: Field status, IGNORED or IGNOUT # LAG=+3600: number of seconds to add to the date of a prism_put_proto to # equal the date of a prism_get_proto that should be matched (see 3.1) –optional # SEQ=+1: position of the field in the sequence of exchange at one particular # coupling time (see 3.2) -required only if $SEQMODE > 1

  39. Step-by-step use of OASIS 3.04.Oasis configuration file namcouple 4.3 Namcouple: I/O-coupling field general description (7/8) 4.3.4 INPUT fields (MPI1,MPI2 only – PSMILe V.0) The field is automatically read by the target model PSMILe at appropriate input times corresponding to the input period. • SOALBEDO SOALBEDO 17 86400 0 SOALBEDO.nc INPUT # SOALBEDO: Name in target model prism_def_var_proto – 8 characters max # 17: Oasis internal label (see driver/src/inipar.f) # 86400: Input period (in seconds) # 0: Number of transformations (always 0) # SOALBEDO.nc: NetCDF input file – 8 characters max. The time variable # in the input file has to be in seconds since beginning of run. # INPUT: Field status

  40. Step-by-step use of OASIS 3.04.Oasis configuration file namcouple 4.3 Namcouple: I/O-coupling field general description (8/8) 4.3.5 OUTPUT fields (MPI1,MPI2 only – PSMILe V.0) The field is automatically written by the source model PSMILe at appropriate output times corresponding to the output period. The name of the output file (one per field) is automatically built based on the field name and initial date of the run ($INIDATE) • TOTOTOTO TOTOTOTO 99 86400 1 OUTPUT # TOTOTOTO: Name in source model prism_def_var_proto – 8 characters max # 99: Oasis internal label (see driver/src/inipar.f) # 86400: Output period (in seconds) # 1: Number of transformations (0, or 1 –>LOCTRANS) # OUTPUT: Field status

  41. Step-by-step use of OASIS 3.04.Oasis configuration file namcouple 4.4 Namcouple: field transformations (1/10) • SOSSTSST SISUTESU 1 86400 5 fldo1.nc out01.nc EXPORTED • 182 152 96 48 topa at31 LAG=+14400 SEQ=+1 • P 2 P 0 • LOCTRANS CHECKIN MOZAIC CHECKOUT REVERSE • Input line for LOCTRANS • Input line for CHECKIN • …

  42. Step-by-step use of OASIS 3.04.Oasis configuration file namcouple 4.4 Namcouple: field transformations (2/10) 4.4.1Pre-processing • LOCTRANS:new!MPI1,MPI2 only – PSMILe V: Time transformation, automatically performed by prism_put_proto. One input line giving the transformation on the field transferred: • INSTANT: no time transformation; instantaneous field; • ACCUMUL: accumulation over the previous coupling period • AVERAGE: average over the previous coupling period; • T_MIN: minimum value for each source grid point over the previous coupling period; • T_MAX: maximum value for each source grid point over the previous coupling period.

  43. Step-by-step use of OASIS 3.04.Oasis configuration file namcouple 4.4 Namcouple: field transformations (3/10) 4.4.1Pre-processing • REDGLO: interpolates from a reduced grid to a global one. Should not be used as interpolations now exist for reduced grids. • MASK: assigns a given value to masked points (for EXTRAP). • EXTRAP: extrapolates the field over masked points values • INVERT: reorders the field. • CHECKIN: calculates statistics on field before interpolation. New input line to compute or not field integrals: ‘INT=1’ or ‘INT=0’. • CORRECT: uses external data to modify the input field. • BLASOLD: linear combination of the field with any other field

  44. Step-by-step use of OASIS 3.04.Oasis configuration file namcouple 4.4 Namcouple: field transformations (4/10) 4.4.2 Interpolation (1/5) Types of grids supported have been extended: • Types 'A', 'B', 'G', 'L', 'Z', and 'Y‘, all ‘lat-lon’ grids still supported. • Type 'U' now for unstructured grid*. • New type 'D' for Gaussian reduced atmospheric grids*. • New type 'LR' for logically-rectangular grids, i.e. that can be described in the (i,j) space (e.g. stretched and rotated grids). Note that 'A', 'B', 'G', 'L', 'Z', and 'Y' are particular cases of 'LR' grids. *All related grid arrays must be 2D and dimensioned (nbr_pts, 1), where nbr_pts is the total number of grid points.

  45. Step-by-step use of OASIS 3.04.Oasis configuration file namcouple 4.4 Namcouple: field transformations (5/10) 4.4.2 Interpolation (2/5) • REDGLO: interpolates from a reduced grid to a global one. Should not be used as interpolations now exist for reduced grids • INTERP: performs the interpolation per se. • BILINEAR: bilinear interpolation* • BICUBIC: bicubic interpolation * • NNEIBOR: nearest-neighbour interpolation* • SURFMESH: conservative remapping -fine to coarse grid* * Source grid must be ‘lat-lon’ ('A', 'B', 'G', 'L', 'Z', or 'Y‘) • GAUSSIAN: nearest-neighbor with a gaussian weight function

  46. Step-by-step use of OASIS 3.04.Oasis configuration file namcouple 4.4 Namcouple: field transformations (6/10) 4.4.2 Interpolation (3/5) • SCRIPR: new! Uses Los Alamos National Laboratory SCRIP 1.4 • See oasis/CHANGES.html for corresponding namcouple input lines • Linking with NetCDF library is mandatory • DISTWGT: N nearest-neighbour -‘LR’, ‘D’, or ‘U’ source grid. • GAUSWGT: N nearest-neighbour with a gaussian weight function – ‘LR’, ‘D’, or ‘U’ source grid. • BILINEAR: bilinear interpolation – ‘LR’, or ‘D’ source grid. • BICUBIC: bilinear interpolation – ‘LR’, or ‘D’ source grid. • …

  47. Step-by-step use of OASIS 3.04.Oasis configuration file namcouple 4.4 Namcouple: field transformations (7/10) 4.4.2 Interpolation (4/5) • SCRIPR: new! Uses Los Alamos National Laboratory SCRIP 1.4 • CONSERV: 1st or 2nd order conservative remapping • Weight for source cell is proportional to area intersected by target cell • 1st order: 'LR', 'D' and 'U‘ grid, or only 'LR‘ grid if grid corners are not given in grids.nc and have to be automatically calculated by Oasis • 2nd order: only 'LR' because of the gradient calculation (not fully tested) • Different normalization options: • FRACAREA: sum of source cell intersected areas is used =>no local flux conservation, but flux value is reasonable • DESTAREA: target cell area is used => local conservation of flux, but flux value may be unreasonable • FRACNNEI: as for FRACAREA, + nearest source neighbour used for target meshes not intersecting any unmasked source meshes.

  48. Step-by-step use of OASIS 3.04.Oasis configuration file namcouple 4.4 Namcouple: field transformations(8/10) 4.4.2 Interpolation(5/5) • MOZAIC: maps the field from a source to a target grid with a grid-mapping file built by the user. • SUBGRID: maps the input field from a coarse grid to a fine grid with a grid-mapping file built by the user and recreates subgrid variability with one of the following operation : • SOLAR: F1out = [(1- F2out ) / (1- F2in ) ] F1in • NONSOLAR: F1out = F1in + (dF1in / dF2in) (F2out – F2in) • NOINTERP: has to be chosen for identical source and target grids.

  49. Step-by-step use of OASIS 3.04.Oasis configuration file namcouple 4.4 Namcouple: field transformations (9/10) 4.4.3 Cooking stage • CONSERV: modifies the output flux to redistribute uniformly the difference between the integral flux on the source grid and the one on target grid, to ensure flux conservation. • BLASNEW: performs a linear combination of the output field with any other output field after the interpolation per se.

  50. Step-by-step use of OASIS 3.04.Oasis configuration file namcouple 4.4 Namcouple: field transformations (10/10) 4.4.4 Post-processing • MASKP: new! masks the fields after interpolation (same generic input line as analysis MASK) • REVERSE: reorders the field after interpolation. • CHECKOUT: calculates statistics on field after interpolation. • GLORED: interpolates from a global Gaussian grid to a reduced grid. If present, must be the last analysis performed.

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