fldread able to switch between several files

[smasson]

fldread must be able to:

• perfom long silulation (for ex. 2-year lonng experiment with forcing file of 1 year long
  
• properly deal with the beginning/end of the year/month when doing time interpolation and using forcing file of 1 year/month long
  
• properly work the the 3 calendars available in NEMO

[smasson]

so more information related to r1132:

time interpolation: interpolate to model frequency of surface boundary condition computation (nn_fsbc in the namelist) or step step-like forcing
clim: .true. if you use climatological data
type of input file: 'yearly'/'monthly' to specify if your forcing fields are stored into files that are 1 year/month long. Note that if your frequency of your forcing is monthly we always define your input files as 'yearly' files.

1) file name:

• if you use climatological files, the file name is given by the structure attribute "file name". Note that the file suffix (.nc or .dimg) is optional.
  
• if you are not using climatological files, structure attribute "file name" will be completed by _yNNNN (_yNNNNmPP) for 'yearly ('monthly') files where NNNN is the year coded with 4 digits and PP is the month code with 2 digits. Note that the file suffix (.nc or .dimg) must be omitted when defining structure attribute "file name".

for example, if the attribute "file name" = 'utau' and we are running year 2008 with a yearly (monthly) file, fldread will look for utau_y2008.nc (utau_y2008m01.nc, utau_y2008m02.nc, ...)

2) begin/end of the year(month) with files that are 1 year(month) long:
let say we are running year 2008 with a yearly file with daily values and we want to perform time interpolation.

• at the beginning of the run, we need data for Dec 31st 2007, so we look for the file xxxx_y2007.nc.
  
  • If this file is found, we are looking for the record number 365 or for the last record of the file xxxx_y2007.nc if it contains less than 365 record (for ex if it contains only December 31 2007 -> useful to save space and speedup file handling).
    
  • If this file is not found, we use constant forcing for the first day (Jan 1st 2008 value is put into the array corresponding to Dec 31st 2007)
• at the end of the run, for Dec 31st 2008, we need values from Jan 1st 2009, so we look for the file xxxx_y2009.nc.
  
  • If this file is found, we are looking for the first record of this file
    
  • If this file is not found, we use constant forcing for the last day (Dec 31st 2008 value is put into the array corresponding to Jan 1st 2009)
    
• if we do a 2-year long simulation with yearly forcing file, fldread should be able to switch from one year to another...
  

3) same story if you use monthly files...

[smasson]

done, see changeset:1132

[nicolasmartin]

Milestone New Surface Module deleted