Add draft Changelog message

Signed-off-by: Lizzie Lundgren <elundgren@seas.harvard.edu>

Author: lizziel

doc/ChangeLog

@@ -1,4 +1,95 @@
+=======
+Tag name: cam6_4_081
+Originator(s): lizziel
+Date: 31 Mar 2025
+One-line Summary: Update HEMCO interface external to HEMCO_CESM 2.1.0
+Github PR URL: https://github.com/ESCOMP/CAM/pull/1221
+
+Purpose of changes (include the issue number and title text for each relevant GitHub issue):
+HEMCO_CESM includes fixes to allow ERS tests of CAM-chem with HEMCO to pass, ERP tests will
+continue to fail with this update but will be fixed in the next version of HEMCO_CESM.
+
+Describe any changes made to build system:
+
+Describe any changes made to the namelist:
+
+List any changes to the defaults for the boundary datasets:
+
+Describe any substantial timing or memory changes:
+
+Code reviewed by: TBD
+
+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
+        - Update HEMCO_CESM version from hemco-cesm2_0_hemco3_9_0 to hemco-cesm2_1_0_hemco3_9_0
 
+M       bld/namelist-files/namelist_defaults_cam.xml
+	- Update default hemco_config_file to read and regrid aviation emissions every timestep
+	- Change default paths of hemco_data_root, hemco_config_file, and hemco_diagn_file
+
+M       cime_config/testdefs/testlist_cam.xml
+	- Fix typos in comments of FCSD_HCO tests
+
+M       src/hemco
+	- Committed hemco submodule (HEMCO_CESM) hash for tag hemco-cesm2_1_0_hemco3_9_0
+
+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:
+
+ERP_Ln9.f09_f09_mg17.FCSD_HCO.derecho_intel.cam-outfrq9s (Overall: FAIL)
+SMS_Ld1.f09_f09_mg17.FCHIST_GC.derecho_intel.cam-outfrq1d (Overall: DIFF)
+ - pre-existing failure due to HEMCO not having reproducible results (issues #1018 and #856)
+
+SMS_D_Ln9.f19_f19_mg17.FXHIST.derecho_intel.cam-outfrq9s_amie (Overall: FAIL)
+SMS_D_Ln9_P1280x1.ne0CONUSne30x8_ne0CONUSne30x8_mt12.FCHIST.derecho_intel.cam-outfrq9s (Overall: FAIL)
+ - pre-existing failures due to build-namelist error requiring CLM/CTSM external update
+
+SMS_D_Ln9_P1280x1.ne30pg3_ne30pg3_mg17.FHISTC_MTt1s.derecho_intel.cam-outfrq9s_Leung_dust (Overall: DIFF)
+ - Missed baseline update from previous CAM tag (cam6_4_063)
+
+derecho/nvhpc/aux_cam:
+
+ERS_Ln9.ne30pg3_ne30pg3_mg17.F2000dev.derecho_nvhpc.cam-outfrq9s_gpu_default (Overall: DIFF)
+ - Expected change in baseline answers.
+
+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:
+
+Summarize any changes to answers, i.e.,
+- what code configurations:
+- what platforms/compilers:
+- nature of change (roundoff; larger than roundoff but same climate; new
+  climate):
+
+If bitwise differences were observed, how did you show they were no worse
+than roundoff?
+
+If this tag changes climate describe the run(s) done to evaluate the new
+climate in enough detail that it(they) could be reproduced, i.e.,
+- source tag (all code used must be in the repository):
+- platform/compilers:
+- configure commandline:
+- build-namelist command (or complete namelist):
+- MSS location of output:
+
+MSS location of control simulations used to validate new climate:
+
+URL for AMWG diagnostics output used to validate new climate:
+
+===============================================================
 ===============================================================
 
 Tag name: cam6_4_081
@@ -2653,8 +2744,21 @@ MSS location of control simulations used to validate new climate:
 URL for AMWG diagnostics output used to validate new climate:
 
 ===============================================================
+=======
+derecho/intel/aux_cam: TBD
+
+derecho/nvhpc/aux_cam: TBD
+
+izumi/nag/aux_cam: TBD
+
+izumi/gnu/aux_cam: TBD
+
+Summarize any changes to answers: bit-for-bit unchanged
+
+>>>>>>> 00d3cfb3 (Add draft Changelog message)
 ===============================================================
 
+===============================================================
 Tag name: cam6_4_057
 Originator(s): brianpm, eaton, nusbaume
 Date: Jan 29 2025
@@ -5077,6 +5181,7 @@ Summarize any changes to answers:
   - F compsets have answer changes due to updated CTSM.
 
 ===============================================================
+=======
 
 Tag name: cam6_4_038
 Originator(s): lizziel