jgfs_atmos_anal.ecf (GFS v17)

Branch / tenant: dev/gfs.v17 (gw_v17) Path: ecf/scripts/gfs/analysis/atmos/jgfs_atmos_anal.ecf Analysis date: 2026-06-11 Method: On-disk v17 worktree analysis.

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Summary

jgfs_atmos_anal.ecf is the NCO production ecFlow task that runs the GSI atmospheric analysis — the core data assimilation step that produces the atmospheric initial conditions for the GFS forecast. It assimilates conventional observations, satellite radiances, GPS-RO, and other data to generate the 3D atmospheric analysis. It calls JGLOBAL_ATMOS_ANALYSIS.

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1. The script itself

Section	Detail
PBS resources	100 nodes, 16 mpiprocs, 8 OMP threads, 128 cpus/node, exclusive host, 80-min wall
Modules	load_modules.sh gsi (GSI analysis stack)
J-Job	JGLOBAL_ATMOS_ANALYSIS
Rocoto breadcrumb	anal.sh

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2. Execution chain

jgfs_atmos_anal.ecf
  +-- JGLOBAL_ATMOS_ANALYSIS
       +-- exglobal_atmos_analysis.sh (or Python)
            +-- GSI variational solver (gsi.x)
            +-- Outer/inner loop minimization
            +-- Produces atmospheric analysis increments

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3. v17-specific notes

• Second largest job: 100 nodes x 128 cpus = 12,800 ranks. Only the forecast is larger.
• GSI-based: uses gsi modules (not JEDI for atmos DA in v17 GFS).
• Hybrid threading: 16 MPI x 8 OMP per node — optimal for GSI's parallelism.
• 80-min walltime — GSI outer/inner loop minimization is computationally intensive.
• Critical path: atmospheric analysis must complete before the forecast can run.
• Exclusive host placement for all 100 nodes.

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4. Change-impact snapshot

Symbol	Risk	Notes
JGLOBAL_ATMOS_ANALYSIS	CRITICAL	Produces atmospheric ICs — forecast depends on it

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Sources

• On-disk v17 worktree: ecf/scripts/gfs/analysis/atmos/jgfs_atmos_anal.ecf.