midas_sstTrial

link to source code

Dependency Diagrams:

Direct Dependency Diagram

program  midas_ssttrial

Purpose

Main program to compute SST background state.

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Algorithm

The background state of SST is computed from the previous SST analysis field using a relaxation towards climatology as follows: \(X_{b}(t) = (X_{a}(t-1) - X_{clim}(t-1)) * \alpha + X_{clim}(t)\), where \(X_{b}(t)\) is a resulting background state at time \(t\), \(X_{a}(t-1)\) is analysis state at time \(t-1\), \(\alpha\) is a relaxation coefficient, \(X_{clim}(t)\) is a climatology state at time \(t\), computed as an interpolation in time between climatological field of the current and the following month for the current day of the month.

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Input and Output Files	Description of file
analysis	In - SST analysis field
climatology	In - 12 monthly climatological SST fields
trial	Out - SST background (trial) field

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Synopsis

Below is a summary of the SSTtrial program calling sequence:

• Initial setups:

• Setup horizontal and vertical grid objects for “analysis grid” from analysis.

• Setup gridStateVector modules.

• Initialize a time objects tim_setup

• Initialize datastamps from climatology file

• Computation

• obgd_getClimatology to read SST climatological fields from a standard file, to interpolate the field in time fot the current day \(t\) in current month \(m\) as follows \(X_{clim}(t) = X_{clim}(m) + (t - 1) /(N - 1) * (X_{clim}(m+1) - X_{clim}(m))\), where \(N\) is a number of days in the current month

• obgd_computeSSTrial to compute the background field and save it into a standard file

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Options

List of namelist blocks that can affect the SSTtrial program.

• The use of SSTtrial program is controlled by the namelist block &NAMSSTTRIAL read by the SSTtrial program.

  • etiketAnalysis etiket to put into output standard file

  • datestampClim list of twelve datestamps of climatological fields in the climatology file

  • alphaClim a parameter defining the relaxation towards climatology.

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Needed modules

• version_mod: MODULE version_mod (prefix=’ver’ category=’8. Low-level utilities and constants’)

• ramdisk_mod: MODULE ramDisk_mod (prefix=’ram’ category=’8. Low-level utilities and constants’)

• utilities_mod: MODULE utilities_mod (prefix=’utl’ category=’8. Low-level utilities and constants’)

• midasmpi_mod: MODULE midasMpi_mod (prefix=’mmpi’ category=’8. Low-level utilities and constants’)

• horizontalcoord_mod: MODULE horizontalCoord_mod (prefix=’hco’ category=’7. Low-level data objects’)

• verticalcoord_mod: MODULE verticalCoord_mod (prefix=’vco’ category=’7. Low-level data objects’)

• timecoord_mod: MODULE timeCoord_mod (prefix=’tim’ category=’7. Low-level data objects’)

• gridstatevector_mod: MODULE gridStateVector_mod (prefix=’gsv’ category=’6. High-level data objects’)

• oceanbackground_mod: MODULE oceanBackground_mod (prefix=’obgd’ category=’1. High-level functionality’)

Routines called

ver_printnameandversion(), mmpi_initialize(), utl_tmg_start(), ram_setup(), obgd_computesstrial(), utl_tmg_stop(), utl_abort(), tim_setup(), tim_getdatestamp(), gsv_setup(), hco_setupfromfile(), vco_setupfromfile()