Update ChangeLog.

Author: nusbaume

doc/ChangeLog

@@ -1,5 +1,77 @@
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+Tag name: cam6_4_128
+Originator(s): jshaw35, fvitt, cacraig, nusbaume
+Date: Oct 30, 2025
+One-line Summary: Correct allocation and assignment error for 'hgt_matrix_half' field in cospsimulator_intr.F90
+Github PR URL: https://github.com/ESCOMP/CAM/pull/1355
+
+Purpose of changes (include the issue number and title text for each relevant GitHub issue):
+  - Fix bug where CAM height interfaces were incorrectly passed to COSP (requires COSP update):
+    https://github.com/ESCOMP/CAM/issues/1354
+  - Bring in an updated default WACCM IC file for the ne30 grid:
+    https://github.com/ESCOMP/CAM/issues/1425
+
+Describe any changes made to build system: N/A
+
+Describe any changes made to the namelist: N/A
+
+List any changes to the defaults for the boundary datasets: N/A
+
+Describe any substantial timing or memory changes: N/A
+
+Code reviewed by: eaton, brianpm, jedwards
+
+List all files eliminated: N/A
+
+List all files added and what they do: N/A
+
+List all existing files that have been modified, and describe the changes:
+
+M       .gitmodules
+M       src/physics/cosp2/src
+ - Update COSP submodule to version 2.1.9
+
+M       src/physics/cam/cospsimulator_intr.F90
+ - Fix 'hgt_matrix_half' bug, and add new COSP diagnostic fields to
+   CAM history output.
+
+M       bld/namelist_files/namelist_defaults_cam.xml
+ - Use spun-up default WACCM IC file for the ne30 grid.
+
+M       cime_config/testdefs/testmods_dirs/cam/cosp_rad_diags/user_nl_cam
+ - Add 'CS_WR_CFODD_REFF_LARGE' to fexcl list in COSP ERC test in order
+   to allow tests to pass (CloudSat variables appear to be task-dependent).
+
+
+If there were any failures reported from running test_driver.sh on any test
+platform, and checkin with these failures has been OK'd by the gatekeeper,
+then copy the lines from the td.*.status files for the failed tests to the
+appropriate machine below.  All failed tests must be justified.
+
+derecho/intel/aux_cam:
+
+  ERC_D_Ln9.f19_f19_mt232.QPC6.derecho_intel.cam-outfrq3s_cosp (Overall: DIFF)
+ - COSP answer changes due to bug fix and new COSP submodule
+
+derecho/nvhpc/aux_cam: ALL PASS
+
+izumi/nag/aux_cam:
+
+ERC_D_Ln9.f10_f10_mt232.FHIST.izumi_nag.cam-outfrq3s_cospsathist (Overall: DIFF)
+ERC_D_Ln9.ne3pg3_ne3pg3_mt232.FHISTC_LTso.izumi_nag.cam-cosp_rad_diags (Overall: DIFF)
+ - COSP answer changes due to bug fix and new COSP submodule
+
+izumi/gnu/aux_cam:
+
+  ERC_D_Ln9.ne3pg3_ne3pg3_mt232.FHIST_C5.izumi_gnu.cam-carma_cosp_rad_diag_mam (Overall: DIFF)
+ - COSP answer changes due to bug fix and new COSP submodule
+
+Summarize any changes to answers: COSP answer changes validated by Brian Medeiros (brianpm)
+
+===============================================================
+===============================================================
+
 Tag name: cam6_4_127
 Originator(s):  courtneyp, jedwards
 Date: Oct 24, 2025