diff --git a/doc/ChangeLog b/doc/ChangeLog index a883f70742..fb0d9cff29 100644 --- a/doc/ChangeLog +++ b/doc/ChangeLog @@ -1,4 +1,139 @@ =============================================================== +Tag name: ctsm5.1.dev103 +Originator(s): sacks (Bill Sacks) +Date: Tue Jul 12 22:27:30 MDT 2022 +One-line Summary: Fix accumulation variables when changing model time step + +Purpose and description of changes +---------------------------------- + +Accumulation variables (e.g., 1-day or 10-day averages) were writing and +reading their accumulation period (expressed in time steps) to the +restart file. This caused incorrect behavior when changing the model +time step relative to what was used to create the initial conditions +file (typically a 30-minute time step). So, for example, if you are +using a 15-minute time step with an initial conditions file that +originated from a run with a 30-minute time step (at some point in its +history), then an average that was supposed to be 10-day instead becomes +5-day; an average that was supposed to be 1-day becomes 12-hour, etc. +(The issue is that the number of time steps in the averaging period was +staying fixed rather than the actual amount of time staying fixed.) + +For our out-of-the-box initial conditions files, this only impacts runs +that use something other than a 30-minute time step. Typically this +situation arises in configurations with an active atmospheric model that +is running at higher resolution than approximately 1 degree. It appears +that the biggest impacts are on VOC emissions and in BGC runs; we expect +the impact to be small (but still non-zero) in prescribed phenology (SP) +runs that don't use VOC emissions. + +This tag fixes this issue by no longer writing or reading accumulation +variables' PERIOD to / from the restart file: this isn't actually needed +on the restart file. + +See some discussion in https://github.com/ESCOMP/CTSM/issues/1789 for +more details, and see +https://github.com/ESCOMP/CTSM/pull/1802#issuecomment-1182743649 for +some discussion of outstanding weirdness that can result for +accumulation variables when changing the model time step. The summary of +that comment is: There could be some weirdness at the start of a run, +but at least for a startup or hybrid run, that weirdness should work +itself out within about the first averaging period. A branch or restart +run could have some longer-term potential weirdness, so for now I think +we should recommend that people NOT change the time step on a branch or +restart run. With (significant?) additional work, we could probably +avoid this additional weirdness, but my feeling is that it isn't worth +the effort right now. In any case, I feel like my proposed fix will +bring things much closer to being correct than they currently are when +changing the time step. + + +Significant changes to scientifically-supported configurations +-------------------------------------------------------------- + +Does this tag change answers significantly for any of the following physics configurations? +(Details of any changes will be given in the "Answer changes" section below.) + + [Put an [X] in the box for any configuration with significant answer changes.] + +[ ] clm5_1 + +[ ] clm5_0 + +[ ] ctsm5_0-nwp + +[ ] clm4_5 + + +Bugs fixed or introduced +------------------------ +CTSM issues fixed (include CTSM Issue #): +- Resolves ESCOMP/CTSM#1789 (A bug in calculating accumulated fields + (24/240 hours averaged) when using a smaller timestep) + +Known bugs found since the previous tag (include issue #): +- ESCOMP/CTSM#1804 (NSTEPS 0 everywhere for accumulation fields on some + initial conditions files) + +Testing summary: +---------------- + + regular tests (aux_clm: https://github.com/ESCOMP/CTSM/wiki/System-Testing-Guide#pre-merge-system-testing): + + cheyenne ---- OK + izumi ------- PASS + + Also ran these tests with comparisons against baselines: + SMS_D_Ld3.f10_f10_mg37.I1850Clm50BgcCrop.cheyenne_intel.clm-shortts + SMS_D_Ld3.f10_f10_mg37.I1850Clm50Sp.cheyenne_intel.clm-shortts + SMS_Lm1.f10_f10_mg37.I1850Clm50Sp.cheyenne_intel.clm-shortts + + + where 'clm-shortts' was a temporary testmod inheriting from default + and adding "./xmlchange ATM_NCPL=96". + +Answer changes +-------------- + +Changes answers relative to baseline: YES, but just for configurations +with a time step that is not the standard 30-minute time step. + + Summarize any changes to answers, i.e., + - what code configurations: Simulations with a time step that is not 30-minutes + - what platforms/compilers: all + - nature of change (roundoff; larger than roundoff/same climate; new climate): + + Not investigated carefully. There can be substantial differences + for VOC emissions, and differences may also be significant in BGC + cases. Differences in SP cases appear to be more limited, since it + looks like the only differences in SP cases (other than VOC + emissions) come from differences in the T10 field (10-day average + temperature), which is used in some photosynthesis calculations. + + For I compset configurations in the test suite, the only + configurations with time steps differing from 30 minutes are: + - mexicocity tests (but for the SP cases in the test suite, the + answer changes are diagnostic-only in a couple of fields, and + the short tests in the test suite don't produce any CLM + history files, so answer changes don't show up) + - vancouver tests that are long enough to produce history files + so that the diagnostic-only differences show up + - USUMB tests + - waccmx_offline (but, as with the mexicocity tests, these tests + are too short to produce history output) + + The only specific tests in the test suite with answer changes are: + SMS_Ld12_Mmpi-serial.1x1_vancouverCAN.I1PtClm50SpRs.cheyenne_gnu.clm-output_sp_highfreq + SMS_D_Lm1_Mmpi-serial.CLM_USRDAT.I1PtClm50SpRs.cheyenne_intel.clm-USUMB_nuopc + SMS_D_Vmct_Lm1_Mmpi-serial.CLM_USRDAT.I1PtClm50SpRs.cheyenne_intel.clm-USUMB_mct + +Other details +------------- +Pull Requests that document the changes (include PR ids): +https://github.com/ESCOMP/CTSM/pull/1802 + +=============================================================== +=============================================================== Tag name: ctsm5.1.dev102 Originator(s): sacks (Bill Sacks) Date: Mon Jul 11 12:14:48 MDT 2022 diff --git a/doc/ChangeSum b/doc/ChangeSum index f6ed448986..dacd37712a 100644 --- a/doc/ChangeSum +++ b/doc/ChangeSum @@ -1,5 +1,6 @@ Tag Who Date Summary ============================================================================================================================ + ctsm5.1.dev103 sacks 07/12/2022 Fix accumulation variables when changing model time step ctsm5.1.dev102 sacks 07/11/2022 Fix LILAC interface to PIO ctsm5.1.dev101 samrabin 07/11/2022 Fix winter wheat sowing window bugs ctsm5.1.dev100 erik 07/05/2022 Start bringing in matrixcn overall options and sparse matrix multiplier code, misc updates