CDO

Hello,

I have a problem in processing IFS files with reduced gaussian and spectral grids. If i want to convert the data stored in

https://swiftbrowser.dkrz.de/download/rp_transfer/TIMEPOI__CAMS__experiment_REANA__integration_ANALYSIS__MLK15to60__2015-01-01_to_2015-01-16.grib

to a regular grid using the command

cdo -s -f nc setgridtype,regular -sp2gp,linear ${file} ${outfile}

, I get fully different results using cdo version 1.9.6 and cdo version 1.9.8. One version is producing data on the whole globe, whereas the other version creates only data in a European region (I have requested the data from MARS only in a specific region). For me it is clear, that the original spectral data are hard to cut for a specific region.

However, I have recognized that the grid description of cdo-196 and cdo-198 is already fully different. CDO version 1.9.6 is giving the following description:

#
# gridID 1
#
gridtype  = spectral
gridsize  = 65792
truncation = 255
complexpacking = 1
#
# gridID 2
#
gridtype  = gaussian_reduced
gridsize  = 13194
ysize     = 100
xname     = lon
xlongname = "longitude" 
xunits    = "degrees_east" 
yname     = lat
ylongname = "latitude" 
yunits    = "degrees_north" 
np        = 128
yvals     = 79.6485269936663 78.9468112809667 78.2450910078212 77.543366944409 76.8416396967821
            76.1399097483681 75.4381774894878 74.7364432387392 74.0347072587468 73.3329697679366
            72.6312309494589 71.9294909580333 71.2277499252598 70.5260079637821 69.8242651705826
            69.1225216296136 68.4207774139149 67.7190325873316 67.0172872059174 66.3155413190886
            65.6137949705788 64.9120481992332 64.2103010396741 63.5085535228595 62.8068056765562
            62.1050575257411 61.4033090929433 60.7015603985375 59.9998114609959 59.2980622971053
            58.596312922156 57.8945633501051 57.1928135937188 56.4910636646978 55.789313573786
            55.0875633308672 54.3858129450494 53.6840624247402 52.982311777713 52.2805610111665
            51.5788101317764 50.8770591457431 50.1753080588334 49.4735568764181 48.7718056035057
            48.0700542447729 47.3683028045918 46.6665512870549 45.9647996959973 45.263048035017
            44.5612963074929 43.8595445166024 43.1577926653356 42.45604075651 41.7542887927827
            41.0525367766618 40.3507847105177 39.649032596592 38.9472804370071 38.2455282337738
            37.5437759887994 36.8420237038942 36.1402713807781 35.4385190210863 34.7367666263753
            34.0350141981274 33.3332617377555 32.6315092466078 31.9297567259713 31.2280041770759
            30.5262516010979 29.8244989991631 29.1227463723498 28.4209937216919 27.719241048181
            27.0174883527696 26.3157356363728 25.6139828998707 24.9122301441104 24.2104773699079
            23.50872457805 22.8069717692958 22.1052189443783 21.403466104006 20.7017132488643
            19.9999603796168 19.2982074969063 18.5964546013566 17.8947016935729 17.1929487741434
            16.4911958436402 15.7894429026201 15.0876899516255 14.3859369911856 13.6841840218169
            12.9824310440241 12.2806780583011 11.5789250651313 10.8771720649885 10.1754190583378
rowlon    = 108 120 120 125 128 144 144 150 160 160 180 180 180 192 192 200 216 216
            216 225 240 240 240 250 250 256 270 270 288 288 288 300 300 320 320 320
            320 324 360 360 360 360 360 360 360 375 375 375 375 384 384 400 400 400
            400 405 432 432 432 432 432 432 432 450 450 450 450 450 480 480 480 480
            480 480 480 480 480 480 486 486 486 500 500 500 500 500 500 500 512 512
            512 512 512 512 512 512 512 512 512 512

In constrast, CDO version 1.9.8 gives the following description:

#
# gridID 1
#
gridtype  = spectral
gridsize  = 65792
truncation = 255
complexpacking = 1
#
# gridID 2
#
gridtype  = gaussian_reduced
gridsize  = 13194
xsize     = 2
ysize     = 100
xname     = lon
xlongname = "longitude" 
xunits    = "degrees_east" 
yname     = lat
ylongname = "latitude" 
yunits    = "degrees_north" 
numLPE    = 128
xvals     = 300 70
yvals     = 79.6485269936663 78.9468112809667 78.2450910078212 77.543366944409 76.8416396967821
            76.1399097483681 75.4381774894878 74.7364432387392 74.0347072587468 73.3329697679366
            72.6312309494589 71.9294909580333 71.2277499252598 70.5260079637821 69.8242651705826
            69.1225216296136 68.4207774139149 67.7190325873316 67.0172872059174 66.3155413190886
            65.6137949705788 64.9120481992332 64.2103010396741 63.5085535228595 62.8068056765562
            62.1050575257411 61.4033090929433 60.7015603985375 59.9998114609959 59.2980622971053
            58.596312922156 57.8945633501051 57.1928135937188 56.4910636646978 55.789313573786
            55.0875633308672 54.3858129450494 53.6840624247402 52.982311777713 52.2805610111665
            51.5788101317764 50.8770591457431 50.1753080588334 49.4735568764181 48.7718056035057
            48.0700542447729 47.3683028045918 46.6665512870549 45.9647996959973 45.263048035017
            44.5612963074929 43.8595445166024 43.1577926653356 42.45604075651 41.7542887927827
            41.0525367766618 40.3507847105177 39.649032596592 38.9472804370071 38.2455282337738
            37.5437759887994 36.8420237038942 36.1402713807781 35.4385190210863 34.7367666263753
            34.0350141981274 33.3332617377555 32.6315092466078 31.9297567259713 31.2280041770759
            30.5262516010979 29.8244989991631 29.1227463723498 28.4209937216919 27.719241048181
            27.0174883527696 26.3157356363728 25.6139828998707 24.9122301441104 24.2104773699079
            23.50872457805 22.8069717692958 22.1052189443783 21.403466104006 20.7017132488643
            19.9999603796168 19.2982074969063 18.5964546013566 17.8947016935729 17.1929487741434
            16.4911958436402 15.7894429026201 15.0876899516255 14.3859369911856 13.6841840218169
            12.9824310440241 12.2806780583011 11.5789250651313 10.8771720649885 10.1754190583378
reducedPoints = 108 120 120 125 128 144 144 150 160 160 180 180 180 192 192 200 216
                216 216 225 240 240 240 250 250 256 270 270 288 288 288 300 300 320
                320 320 320 324 360 360 360 360 360 360 360 375 375 375 375 384 384
                400 400 400 400 405 432 432 432 432 432 432 432 450 450 450 450 450
                480 480 480 480 480 480 480 480 480 480 486 486 486 500 500 500 500
                500 500 500 512 512 512 512 512 512 512 512 512 512 512 512

To make it short: only the cdo-version 1.9.6 is reasonable regarding the physical content of the data.

Is there any clue about the problem?

Best regards,

Ronny