Support for removing levels from EN files

[pesei]

For tropospheric dispersion problems, atmospheric layers higher than ca. 100 hPa are rarely needed. However, they may have been extracted from ECMWF MARS into the EN files (some versions of the extraction routines haven't offered the option to take only a part of the levels).

This causes the EN files to be unnecessarily large, and it creates additional overhead in verttransform.f90 and calcpv.f90. As recent experiences have shown, with 1-h temporal resolution, these two subroutines can form a bottleneck. It is therefore worthwhile to offer fixes for this problem. Options:

1. A script using the GRIB_API to remove certain layers
2. An option in FLEXPART to not ingest certain layers.

Probably implementing both solutions would be best.

[anphi]

I already started to work on the first option:

I used the grib_filter command to cut out some levels of a gribfile.
The filter rule was:

if ( typeOfLevel is "surface" || level >59 ) {
   set packingType="grid_simple";
   write "[file].new" ;
}

In my test case it worked. Unfortunately, with a second test case it failed with the error message:

 Welcome to FLEXPART Version 9.0
 FLEXPART is free software released under the GNU General Public License.
 
 
# of vertical levels in ECMWF data:      79      0
 
Mother domain:
  Longitude range:    -179.50     180.50   Grid distance:       0.50
  Latitude range:     -90.00      90.00   Grid distance:       0.50
 
  Releasepoints allocated:            1
  Particles allocated for this run:      2000000 , released in simulation: 
     1000000
  Allocating fields for nested and global output (x,y):          720         360
sorry: t not in [k]

I am still working on this problem and contacted the ECMWF help desk.

[pesei]

Option 2 is now impemented in the lastest version of the extraction softwarew, see ticket:130

[dearn]

If someone wants to do this without reextracting the files, the filter rule needs to be slightly different. It is important to note that, with the filter above, nlev_ec stays unmodified in the GRIB files, which means that gridcheck does not handle properly the a and b parameters for the vertical discretisation (actually I was getting running FLEXPART but with wrong FLEXPART model heights - the first one was corresponding to the second when running wiht the original uncut ECMWF GRIB files). In addition, I have had to pass the pv array explicitly ( where the coefficients a and b are stored) which means I first dumped the array using grib_dump -d, putting the array in the filter, and erasing those values not needed.

An example of the filter_rule to erase the uppermost ten levels is written here:

if (level > 10 ){
set PVPresent=1;
set level = level - 10 ;
set pv={
  4.2879241943e+01, 5.4955463409e+01, 6.9520576477e+01, 8.6895881653e+01, 1.0741574097e+02,
  1.3142550659e+02, 1.5927940369e+02, 1.9133856201e+02, 2.2796894836e+02, 2.6953958130e+02,
  3.1642074585e+02, 3.6898236084e+02, 4.2759249878e+02, 4.9261602783e+02, 5.6441345215e+02,
  6.4333990479e+02, 7.2974414062e+02, 8.2396783447e+02, 9.2634490967e+02, 1.0372011719e+03,
  1.1568536377e+03, 1.2856103516e+03, 1.4237701416e+03, 1.5716229248e+03, 1.7294489746e+03,
  1.8975192871e+03, 2.0760959473e+03, 2.2654316406e+03, 2.4657705078e+03, 2.6773481445e+03,
  2.9003913574e+03, 3.1351193848e+03, 3.3817436523e+03, 3.6404682617e+03, 3.9114904785e+03,
  4.1949306641e+03, 4.4908173828e+03, 4.7991494141e+03, 5.1198950195e+03, 5.4529907227e+03,
  5.7983447266e+03, 6.1560742188e+03, 6.5269467773e+03, 6.9118706055e+03, 7.3118691406e+03,
  7.7274121094e+03, 8.1593540039e+03, 8.6085253906e+03, 9.0764003906e+03, 9.5626826172e+03,
  1.0065978516e+04, 1.0584631836e+04, 1.1116662109e+04, 1.1660067383e+04, 1.2211547852e+04,
  1.2766873047e+04, 1.3324668945e+04, 1.3881331055e+04, 1.4432139648e+04, 1.4975615234e+04,
  1.5508256836e+04, 1.6026115234e+04, 1.6527322266e+04, 1.7008789062e+04, 1.7467613281e+04,
  1.7901621094e+04, 1.8308433594e+04, 1.8685718750e+04, 1.9031289062e+04, 1.9343511719e+04,
  1.9620042969e+04, 1.9859390625e+04, 2.0059931641e+04, 2.0219664062e+04, 2.0337863281e+04,
  2.0412308594e+04, 2.0442078125e+04, 2.0425718750e+04, 2.0361816406e+04, 2.0249511719e+04,
  2.0087085938e+04, 1.9874025391e+04, 1.9608572266e+04, 1.9290226562e+04, 1.8917460938e+04,
  1.8489707031e+04, 1.8006925781e+04, 1.7471839844e+04, 1.6888687500e+04, 1.6262046875e+04,
  1.5596695312e+04, 1.4898453125e+04, 1.4173324219e+04, 1.3427769531e+04, 1.2668257812e+04,
  1.1901339844e+04, 1.1133304688e+04, 1.0370175781e+04, 9.6175156250e+03, 8.8804531250e+03,
  8.1633750000e+03, 7.4703437500e+03, 6.8044218750e+03, 6.1685312500e+03, 5.5643828125e+03,
  4.9937968750e+03, 4.4573750000e+03, 3.9559609375e+03, 3.4892343750e+03, 3.0572656250e+03,
  2.6591406250e+03, 2.2942421875e+03, 1.9615000000e+03, 1.6594765625e+03, 1.3875468750e+03,
  1.1432500000e+03, 9.2650781250e+02, 7.3499218750e+02, 5.6806250000e+02, 4.2441406250e+02,
  3.0247656250e+02, 2.0248437500e+02, 1.2210156250e+02, 6.2781250000e+01, 2.2835937500e+01,
  3.7578129768e+00, 0.0000000000e+00, 0.0000000000e+00,
  0.0000000000e+00, 0.0000000000e+00,
  0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00,
  0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00,
  0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00,
  0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00,
  0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00,
  0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00,
  0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00,
  0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00, 0.0000000000e+00,
  0.0000000000e+00, 0.0000000000e+00, 3.8199999608e-08, 6.7607002165e-06, 2.4348000807e-05,
  5.8921999880e-05, 1.1191429803e-04, 1.9857739971e-04, 3.4037968726e-04, 5.6155532366e-04,
  8.8969792705e-04, 1.3528055279e-03, 1.9918379840e-03, 2.8571242001e-03, 3.9709536359e-03,
  5.3778146394e-03, 7.1333767846e-03, 9.2614600435e-03, 1.1806022376e-02, 1.4815628529e-02,
  1.8318451941e-02, 2.2354844958e-02, 2.6963520795e-02, 3.2176095992e-02, 3.8026399910e-02,
  4.4547960162e-02, 5.1773015410e-02, 5.9728413820e-02, 6.8448252976e-02, 7.7958308160e-02,
  8.8285736740e-02, 9.9461667240e-02, 1.1150465161e-01, 1.2444812804e-01, 1.3831289113e-01,
  1.5312503278e-01, 1.6891041398e-01, 1.8568944931e-01, 2.0349121094e-01, 2.2233286500e-01,
  2.4224400520e-01, 2.6324188709e-01, 2.8535401821e-01, 3.0859845877e-01, 3.3293908834e-01,
  3.5825419426e-01, 3.8436332345e-01, 4.1112476587e-01, 4.3839120865e-01, 4.6600329876e-01,
  4.9380031228e-01, 5.2161920071e-01, 5.4930114746e-01, 5.7669216394e-01, 6.0364806652e-01,
  6.3003581762e-01, 6.5573596954e-01, 6.8064302206e-01, 7.0466899872e-01, 7.2773873806e-01,
  7.4979656935e-01, 7.7079755068e-01, 7.9071676731e-01, 8.0953603983e-01, 8.2725608349e-01,
  8.4388113022e-01, 8.5943180323e-01, 8.7392926216e-01, 8.8740754128e-01, 8.9990049601e-01,
  9.1144818068e-01, 9.2209565639e-01, 9.3188077211e-01, 9.4085955620e-01, 9.4906443357e-01,
  9.5654952526e-01, 9.6335172653e-01, 9.6951341629e-01, 9.7507840395e-01, 9.8007160425e-01,
  9.8454189301e-01, 9.8849952221e-01, 9.9198400974e-01, 9.9500250816e-01, 9.9763011932e-01,
  1.0000000000e+00};
write;
#append;
}
if ( typeOfLevel is 'surface' || typeOfLevel is 'meanSea' ||typeOfLevel is 'heightAboveGround' || typeOfLevel is 'depthBelowLandLayer'){
#append;
write;
}