Changes between Version 11 and Version 12 of DevelopmentActivities/OasisDriver
- Timestamp:
- 2014-06-17T11:26:50+02:00 (10 years ago)
Legend:
- Unmodified
- Added
- Removed
- Modified
-
DevelopmentActivities/OasisDriver
v11 v12 2 2 == Introduction == 3 3 4 Today ORCHIDEE is designed to be called by a subroutine independently on each processor. This is implemented for instance in the traditional driver (dim2_driver.f90) :4 Today ORCHIDEE is designed to be called by a subroutine independently on each processor. This is implemented for instance in the traditional off-line driver (dim2_driver.f90) : 5 5 6 6 [[Image(wiki:OasisDriver:Witout_OASIS.png, 350px)]] 7 7 8 This assumes that the domain decomposition of the atmospheric model or the driverare the same. It also means that the processors which have no land point to deal with are waiting for the others to finish.8 This assumes that the domain decomposition of the atmospheric model (or the driver) and ORCHIDEE are the same. It also means that the processors which have no land point to deal with are waiting for the others to finish. 9 9 10 10 In order to avoid these issues and generalise the coupling of ORCHIDEE with other atmospheric components, the OASIS-MCT coupler can be used. In this case the atmosphere can work on any number of processors and ORCHIDEE on a distinct set of processors. This is exemplified in the driver2oasis presented below. Here, the driver (driver2oasis.f90) which mimics the atmosphere, is a single processor code which just reads some forcing files and provides that data to OASIS. It is a prototype for any atmospheric model which would send the same fields from its n processors to OASIS. … … 12 12 [[Image(wiki:OasisDriver:With_OASIS.png, 350px)]] 13 13 14 In the OASIS approach to coupling a number of advantages are gained :14 In the OASIS approach to coupling, a number of advantages are gained : 15 15 16 16 * The atmosphere can run on a different set of processors than the land surface and have its own domain decomposition. … … 22 22 * In the same way, once the land surface has returned the variables needed by the atmosphere (i.e. after solving the surface energy balance) it can continue to work and prepare the next time step. 23 23 24 * The land surface model is an independent executable which has its own restart mechanism and history system and can thus be developed in dependently from the atmospheric component.24 * The land surface model is an independent executable which has its own restart mechanism and history system and can thus be developed in a more autonomous way. 25 25 26 26 == The driver for OASIS : driver2oasis.f90 == … … 32 32 For the moment this code only reads compressed by gathering forcing files which contain a sufficient amount of meta-data ([attachment:Description_Forcing_Files.pdf]). 33 33 34 Th is code is aimed at runningonly on one processor. It should not be a limiting factor in the execution time as it only reads once the forcing and then only does some simple time interpolations. Furthermore these interpolations are done while ORCHIDEE runs, i.e. it is not blocked by an oasis_get call.34 The code is designed to run only on one processor. It should not be a limiting factor in the execution time as it only reads once the forcing and then only does some simple time interpolations. Furthermore these interpolations are done while ORCHIDEE runs, i.e. it is not blocked by an oasis_get call. 35 35 36 36 == The fields which OASIS exchanges between the atmosphere and the surface == … … 78 78 The main, in the FORTRAN sense is very similar to the intersurf.f90 which as been used up to now. The main difference is that it obtains the atmospheric data by issuing the needed OASIS_get calls. It will perform the following actions : 79 79 80 * Set-up the domain decomposition of the grid it has been given. 80 * Read the grid description in a netCDF file. 81 82 * Set-up the domain decomposition for the grid. 81 83 82 84 * Set-up the restart and history mechanisms. … … 86 88 * Call sechiba_main 87 89 88 * Send to the atmosphere the flux computed90 * Send to the atmosphere (or the driver) the computed fluxes. 89 91 90 92 * Write to the history files … … 94 96 == Configuration of this ORCHIDEE version == 95 97 96 As OASIS does not provide a mechanism to exchange time and grid descriptions between two coupled models some extra information needed to be added to the run.def. Obviously the coupling mechanism itself also needs to be documented in the namcouple of OASIS.98 As OASIS does not provide a mechanism to exchange time and grid descriptions between two coupled models, some extra information needed to be added to the run.def and read from other files. Obviously the coupling mechanism itself also needs to be documented in the namcouple of OASIS. 97 99 98 100 === Added information in the run.def === 99 101 100 * The information on the length of the simulation which has always been used in therun.def is insufficient to ensure that the driver and ORCHIDEE run over the same period. In order to solve this the run.def now needs to include a start and an end date for the simulation. The two keywords are (The dates provided need to be in the ISO format and be exact (include hour, minutes and seconds).) :102 * The information on the length of the simulation which has been provided previously in run.def is insufficient to ensure that the driver and ORCHIDEE run over the same period. In order to solve this the run.def now needs to include a start and an end date for the simulation. The two keywords are (The dates provided need to be in the ISO format and be exact (include hour, minutes and seconds).) : 101 103 - START_DATE = 1990-01-01 0:0:0 102 104 - END_DATE = 1990-03-01 0:0:0 … … 106 108 - TIME_STEP = 900 107 109 108 * In the same way, the distribution of the average rainfall provided by the forcingover the finer time stepping of the model is given in seconds :110 * In the same way, the distribution of the average rainfall, provided by the forcing, over the finer time stepping of the model is given in seconds : 109 111 - SPRED_PREC_SEC = 3600 110 112 111 * As the time interval to be simulated the more than one forcing file might be needed. Thus the option which names the forcing file accepts a list of files :113 * The time interval to be simulated can cover more than one forcing file. Thus the option which names the forcing file accepts a list of files : 112 114 - FORCING_FILE = WFDEI_CRU_2008.nc WFDEI_CRU_2009.nc 113 115 … … 121 123 === The grid description file === 122 124 123 The grid file is generated by the driver2oasis or by the atmospheric model. In the case of an off-line simulation this file is generated in an initialisation call (driver2oasis -init) based on the forcing file. The program will read the forcing file, compute the land/ocean mask and other ancillary information. We will ensure that orchideeoasis.f90 (the main program for ORCHIDEE) will be able to read also grid description files of all atmospheric models it is coupled to. WRF will be the first case implemented. 125 The grid file (in netCDF format) is generated by the driver2oasis or by the atmospheric model. In the case of an off-line simulation this file is generated in an initialisation call (driver2oasis -init) based on the forcing file. The program will read the forcing file, compute the land/ocean mask and other ancillary information. 126 127 We will ensure that orchideeoasis.f90 (the main program for ORCHIDEE) will be able to read also grid description files of other atmospheric models it is coupled to. WRF will be the first case implemented. 124 128 125 129 This file needs to provide the following information to ORCHIDEE : … … 159 163 == Execution of the model coupled to the driver == 160 164 161 As OASIS is linked into both models (driver2oasis and orchideeoasis) the execution of the coupled model is simply achievedby one mpirun command. It can have the following structure :165 As OASIS-MCT is linked into both models (driver2oasis and orchideeoasis) the execution of the coupled model is simply achieved by one mpirun command. It can have the following structure : 162 166 163 167 mpirun -n $PEDRIV driver2oasis : -n $PEORCH orchideeoasis 164 168 165 where : PEDRIV=1 and PEORCH=$(($NSLOTS-$PEDRIV)), i.e. only one processor is forthe driver and all others work on ORCHIDEE.169 where : PEDRIV=1 and PEORCH=$(($NSLOTS-$PEDRIV)), i.e. only one processor is dedicated to the driver and all others work on ORCHIDEE. 166 170 167 171 In the execution directory the 3 configuration files presented above need to be present :