Update ChangeLog

Author: kuanchihwang

doc/ChangeLog

@@ -1,5 +1,92 @@
 ===============================================================
 
+Tag name: cam6_4_106
+Originator(s): kuanchihwang
+Date: July 23, 2025
+One-line Summary: Add "_mpas" suffix and use "ncol" dimension for MPAS-specific output variables
+Github PR URL: https://github.com/ESCOMP/CAM/pull/1338
+
+Purpose of changes (include the issue number and title text for each relevant GitHub issue):
+
+  This PR changes how MPAS-specific output variables are written to history files:
+
+    1. Add the "_mpas" suffix, making it clear that these variables are specific to MPAS and
+       are different from the standard CAM ones.
+    2. Change the dimension name from "nCells" to "ncol", improving the compatibility with
+       certain tools like ncremap from NetCDF Operator.
+
+  Restart files are not affected.
+
+  Closes #1323 (MPAS outputs w, theta, and rho)
+
+Describe any changes made to build system:
+
+  None
+
+Describe any changes made to the namelist:
+
+  None
+
+List any changes to the defaults for the boundary datasets:
+
+  None
+
+Describe any substantial timing or memory changes:
+
+  None
+
+Code reviewed by:
+
+  PeterHjortLauritzen, cacraigucar
+
+List all files eliminated:
+
+  None
+
+List all files added and what they do:
+
+  None
+
+List all existing files that have been modified, and describe the changes:
+
+  M       src/dynamics/mpas/stepon.F90
+    * Add the "_mpas" suffix to MPAS-specific output variables
+    * Change the dimension name of MPAS-specific output variables from "nCells" to "ncol"
+
+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:
+
+  SMS_D_Ln9_P1280x1.ne0CONUSne30x8_ne0CONUSne30x8_mt12.FCHIST.derecho_intel.cam-outfrq9s (Overall: FAIL) details:
+    FAIL SMS_D_Ln9_P1280x1.ne0CONUSne30x8_ne0CONUSne30x8_mt12.FCHIST.derecho_intel.cam-outfrq9s SETUP
+      * Pre-existing failures due to build-namelist error requiring CLM/CTSM external update
+
+derecho/nvhpc/aux_cam:
+
+  All pass
+
+izumi/nag/aux_cam:
+
+  All pass
+
+izumi/gnu/aux_cam:
+
+  All pass
+
+CAM tag used for the baseline comparison tests if different than previous
+tag:
+
+  cam6_4_105
+
+Summarize any changes to answers:
+
+  None
+
+===============================================================
+
 Tag name: cam6_4_105
 Originator(s): eaton
 Date: 22 July 2025