Add thinning for ice obs when used in LETKF#153
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JohnSteffen-NOAA
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Jul 25, 2025
guillaumevernieres
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Jul 25, 2025
guillaumevernieres
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# Description Use thinning for AMSR2 ice observations in LETKF (both makes sense scientifically, and brings down the runtime to ~8min on hera on 480 MPI tasks). Since thinning is done with "reduce obs space" option, we need to run it only once. Hence the switch to using linear observer here: in this case filters are only run on ensemble mean. # Companion PRs NOAA-EMC/jcb-gdas#153 # Issues Resolves #1542 # Automated CI tests to run in Global Workflow <!-- Which Global Workflow CI tests are required to adequately test this PR? --> - [ ] atm_jjob <!-- JEDI atm single cycle DA !--> - [ ] C96C48_ufs_hybatmDA <!-- JEDI atm cycled DA !--> - [x] C96C48_hybatmsnowDA <!-- JEDI snow cycled DA !--> - [ ] C96_gcafs_cycled <!-- JEDI aerosol cycled DA !--> - [x] C48mx500_3DVarAOWCDA <!-- JEDI low-res marine 3DVar cycled DA !--> - [x] C48mx500_hybAOWCDA <!-- JEDI marine hybrid envar cycled DA !--> - [ ] C96C48_hybatmDA <!-- GSI atm cycled DA !--> --------- Co-authored-by: Anna Shlyaeva <anna.v.shlyaeva@noaa.gov>
DavidNew-NOAA
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# Description Use thinning for AMSR2 ice observations in LETKF (both makes sense scientifically, and brings down the runtime to ~8min on hera on 480 MPI tasks). Since thinning is done with "reduce obs space" option, we need to run it only once. Hence the switch to using linear observer here: in this case filters are only run on ensemble mean. # Companion PRs NOAA-EMC/jcb-gdas#153 # Issues Resolves #1542 # Automated CI tests to run in Global Workflow <!-- Which Global Workflow CI tests are required to adequately test this PR? --> - [ ] atm_jjob <!-- JEDI atm single cycle DA !--> - [ ] C96C48_ufs_hybatmDA <!-- JEDI atm cycled DA !--> - [x] C96C48_hybatmsnowDA <!-- JEDI snow cycled DA !--> - [ ] C96_gcafs_cycled <!-- JEDI aerosol cycled DA !--> - [x] C48mx500_3DVarAOWCDA <!-- JEDI low-res marine 3DVar cycled DA !--> - [x] C48mx500_hybAOWCDA <!-- JEDI marine hybrid envar cycled DA !--> - [ ] C96C48_hybatmDA <!-- GSI atm cycled DA !--> --------- Co-authored-by: Anna Shlyaeva <anna.v.shlyaeva@noaa.gov>
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Thin AMSR2 ice concentration obs, only for LETKF to avoid messing with gfsv17 configuration.
I ran a test and confirmed that obs are thinned in LETKF, and not thinned in Var.
Note: requires gdas PR to work correctly.