I'm trying to figure out some subtleties of the forcing XML settings. Here is the scenario: I run a simulation (HIST competition) from 1901-1990 with the the following settings:
DATM_CLMNCEP_YR_ALIGN: 1901
DATM_CLMNCEP_YR_START: 1901
DATM_CLMNCEP_YR_END: 2014
RUN_STARTDATE: 1901-01-01
Then I run two more simulations both starting in 1990 for 25 years using the restart file from the previous case as initial conditions. In the first I only change:
RUN_STARTDATE: 1990-01-01
In the second I change:
DATM_CLMNCEP_YR_ALIGN: 1990
DATM_CLMNCEP_YR_START: 1990
RUN_STARTDATE: 1990-01-01
When I look at the forcing history output (TBOT, PCO2, etc.) from these two 1990 runs they are identical except for the first and last months. What I think is happening is that in the former case 1990-01-01 is being connected (interpolated) to 1989-12-01 and 2014-12-31 is being connected to 1901-01-01 while in the later case 1990-01-01 is being connected to 2014-12-31 and 2014-12-31 to to 1990-01-01. Is this correct?
I usually use the former approach but I was curious if the changes would have an effect. If I had used DATM_CLMNCEP_YR_ALIGN = 1989 for the last case would 1990-01-01 have been identical for the two cases?
Finally, I can't seem to figure out what DATM_CLMNCEP_YR_ALIGN does. In previous experiments I have seen that changing DATM_CLMNCEP_YR_ALIGN does not seem to do anything if the forcing dates overlap the simulation dates. For example, 1995 seems to align with 1995 if I'm using 1900-2000 forcing no matter what, although I am less confident about this statement.
The differences in forcing are subtle in these examples and are not likely to answer changing but understanding these settings would be helpful for some more exotic simulations.
DATM_CLMNCEP_YR_ALIGN: 1901
DATM_CLMNCEP_YR_START: 1901
DATM_CLMNCEP_YR_END: 2014
RUN_STARTDATE: 1901-01-01
Then I run two more simulations both starting in 1990 for 25 years using the restart file from the previous case as initial conditions. In the first I only change:
RUN_STARTDATE: 1990-01-01
In the second I change:
DATM_CLMNCEP_YR_ALIGN: 1990
DATM_CLMNCEP_YR_START: 1990
RUN_STARTDATE: 1990-01-01
When I look at the forcing history output (TBOT, PCO2, etc.) from these two 1990 runs they are identical except for the first and last months. What I think is happening is that in the former case 1990-01-01 is being connected (interpolated) to 1989-12-01 and 2014-12-31 is being connected to 1901-01-01 while in the later case 1990-01-01 is being connected to 2014-12-31 and 2014-12-31 to to 1990-01-01. Is this correct?
I usually use the former approach but I was curious if the changes would have an effect. If I had used DATM_CLMNCEP_YR_ALIGN = 1989 for the last case would 1990-01-01 have been identical for the two cases?
Finally, I can't seem to figure out what DATM_CLMNCEP_YR_ALIGN does. In previous experiments I have seen that changing DATM_CLMNCEP_YR_ALIGN does not seem to do anything if the forcing dates overlap the simulation dates. For example, 1995 seems to align with 1995 if I'm using 1900-2000 forcing no matter what, although I am less confident about this statement.
The differences in forcing are subtle in these examples and are not likely to answer changing but understanding these settings would be helpful for some more exotic simulations.