BOMEX with the CPE SHOC parameters (Sep 2026)

Question. Do the machine-learning-calibrated SHOC parameter sets of Zhang et al. (2026, GRL, doi:10.1029/2025GL120241; "CPE" ranks 1-3, from Peter Bogenschutz) make E3SM/SHOC's BOMEX cumulus-like, i.e. a cloud fraction that peaks at cloud base (~0.06 in the LES) and decays upward?

Answer: no. In the full-physics EAM-SCM (Brian's setup, radiation off) and in the SHOC standalone driver alike, on all 4 dz x 4 dt combinations, the CPE sets keep the cloud-fraction maximum near cloud top, with peak values of 0.2-0.7 (LES 0.06) and LWP of 45-90 g/m2 in most cells (LES 8, default SHOC 5-20). They do deepen the cloud layer (120-165 hPa vs 45-90 hPa for default SHOC; LES ~120 hPa), and at dz = 50 m or finer with dt ≤ 60 s they produce an intermittent, pulsing cloud that the default does not. Hours 4-6 means; see the metrics table for every cell.

• EAM-SCM cloud fraction, 4 dz x 4 dt, all groups + LES (grey)  |  same for cloud liquid
• SHOC standalone cloud fraction, 4 dz x 4 dt, all sets + LES  |  same for cloud water
• metrics table (max cloud fraction, layer depth, LWP, cloud cover) per group x dz x dt, LES row on top

Figure decks (same page order everywhere)

cpe1fix = CPE rank 1 including shoc_c_diag_3rd_mom (Peter's C_diag_w3), which Brian's cpe1 runs omitted. The EAM-SCM groups use Brian's template and code (E3SM-fork eam_scm_bugfixes @ 4c07d90b57); CPE values enter only through user_nl_eam. Standalone runs: shoc_in_and_out driver, 12 h, dx = 100 km, same IC files as the SCM.

SHOC+MF in the standalone driver (preliminary, 2026-09-10)

• README_shocmf.md - settings (paper-era MF configuration, two values of the TKE dissipation constant), 4-6 h metrics tables, caveats
• cloud fraction grid, zoomed: LES, SHOC default, SHOC+MF  |  all sets on four pages (profiles, cloud-fraction and cloud-water grids, time series) with the LES
• deck: shoc_BOMEX_shocmf_inout_f90.ymin710.pdf
• one line: SHOC+MF is cumulus-like on all 16 dz x dt runs (cloud-fraction maximum 0.03-0.07 at cloud base, LWP 6-11 g/m2; LES 0.06, 8) and nearly insensitive to dz and dt.

Data and scripts

• metrics CSVs: metrics_fullphysne30*_4-6h.csv, standalone/metrics_4-6h.csv
• case archive (h0, atm_in, logs, scripts): /global/cfs/cdirs/m4359/mchinita/bomex_cpe_archive_20260901/; LES reference files: /global/cfs/cdirs/m4359/mchinita/les_reference/BOMEX_Matheou/
• scripts: mr_scm branch main_BOMEXmods, e3sm_scm_scripts/code_test_archive/20260901_e3sm_master_bomex_fullphys_cpe/ (EAM-SCM) and e3sm_scm_scripts/in_and_out_scripts/ (standalone)