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CMIP6 Anomaly Forcing Details

J

Joshua Rady

Joshua Rady
New Member
I have a couple of questions about using CMIP6 anomaly forcing. I have switched from the default (CMIP5 era?) anomaly forcing to the CMIP6 forcing referenced in the documentation, e.g. /glade/p/cesmdata/cseg/inputdata/atm/datm7/anomaly_forcing/CMIP6-SSP1-2.6/. These files don't seem to have a dedicated domain file but work with the default domain file (/glade/p/cesmdata/cseg/inputdata/atm/datm7/anomaly_forcing/domain.permafrostRCN). However, there are no U or V wind files for any SSP. Should I omit wind when using CMIP6 anomaly forcing or is there another version of these files that includes wind files?

Second, according to the anomaly files the CMIP6 anomaly forcing uses 2000-2014 as a reference, while the older default files use 2001-2013. Is is important to match the climate cycling (DATM_CLMNCEP_YR_START & DATM_CLMNCEP_YR_END) with these years exactly or is safe to use a subset of these years? I can't tell whether underlying historical climatology is being used in a detrended form to only provide the variance properties or if the anomaly is calculated against specific years of raw data. If the latter changing the years for the cycling would introduce a bia.

As a side note I had to convert the CMIP6 anomaly files to netCDF5 to get simulations to run, which is part of why I wonder if I don't have the latest version.
 
O

oleson

Keith Oleson
CSEG and Liaisons
Staff member
The anomaly forcing data has been updated (includes wind files) but not yet placed in the location referenced by the documentation. There is a least one issue (CTSM issue) associated with this process:

github.com

Update Anomaly forcing data and contrib script · Issue #1300 · ESCOMP/CTSM

@swensosc has updates to the ssp_anomaly_forcing_smooth in tools/contrib that also processes winds among other changes. The current script was used to create the data under $DIN_LOC_ROOT/tm/datm7/a...
github.com github.com

The data is currently at:

/glade/p/cgd/tss/people/oleson/anomaly_forcing

I personally have done one simulation with this data (quite some time ago however) and it appears to give reasonable/expected results The case directory is here:

/glade/work/oleson/release-clm5.0.30/cime/scripts/clm50_r-clm5.0.30_1deg_GSWP3V1_iso_SSP3-7_AnomalyF2

Regarding your second question, perhaps @swensosc can answer.
 
C

caufj

Jing Fu
New Member
oleson said:
The anomaly forcing data has been updated (includes wind files) but not yet placed in the location referenced by the documentation. There is a least one issue (CTSM issue) associated with this process:

github.com

Update Anomaly forcing data and contrib script · Issue #1300 · ESCOMP/CTSM

@swensosc has updates to the ssp_anomaly_forcing_smooth in tools/contrib that also processes winds among other changes. The current script was used to create the data under $DIN_LOC_ROOT/tm/datm7/a...
github.com github.com

The data is currently at:

/glade/p/cgd/tss/people/oleson/anomaly_forcing

I personally have done one simulation with this data (quite some time ago however) and it appears to give reasonable/expected results The case directory is here:

/glade/work/oleson/release-clm5.0.30/cime/scripts/clm50_r-clm5.0.30_1deg_GSWP3V1_iso_SSP3-7_AnomalyF2

Regarding your second question, perhaps @swensosc can answer.
Click to expand...
I set up a case using the I2000ClmSpGs compset and made the anomaly forcing by myself (by calculating the anomaly of a cmip6 projection dataset based on another historical forcing data). I also changed the user_nl_datm and user_nl_cpl file, and added the relevant user* stream files in the run directory. But I found that in the outputs, only 2m air temperature (TSA) was updated and no other variables show any difference compared to the case not using anomaly forcing data. Why would this happen? Is it happening because I have some potential errors in the data generating process or should it only run with the default anomaly forcing data? Thanks!
 
C

caufj

Jing Fu
New Member
oleson said:
The anomaly forcing data has been updated (includes wind files) but not yet placed in the location referenced by the documentation. There is a least one issue (CTSM issue) associated with this process:

github.com

Update Anomaly forcing data and contrib script · Issue #1300 · ESCOMP/CTSM

@swensosc has updates to the ssp_anomaly_forcing_smooth in tools/contrib that also processes winds among other changes. The current script was used to create the data under $DIN_LOC_ROOT/tm/datm7/a...
github.com github.com

The data is currently at:

/glade/p/cgd/tss/people/oleson/anomaly_forcing

I personally have done one simulation with this data (quite some time ago however) and it appears to give reasonable/expected results The case directory is here:

/glade/work/oleson/release-clm5.0.30/cime/scripts/clm50_r-clm5.0.30_1deg_GSWP3V1_iso_SSP3-7_AnomalyF2

Regarding your second question, perhaps @swensosc can answer.
Click to expand...
BTW, I am running regional cases with CLM_USRDAT resolution
 
J

Joshua Rady

Joshua Rady
New Member
It took a while to look though the file, my notes, issue # 1300, the related issues.

You kindly shared the files at /glade/p/cgd/tss/people/oleson/anomaly_forcing with me for a previous issue. However, I mistakenly concluded that they were older than the files in /glade/p/cesmdata/cseg/inputdata/atm/datm7/anomaly_forcing/. (I don't known how since both internal and file system creation dates are newer). I will try using these forcing files to a quick test simulation.
 
O

oleson

Keith Oleson
CSEG and Liaisons
Staff member
@caufj ,there aren't any required modifications to user_nl_cpl related to anomaly forcing. You should have the following user_* files in your case directory (not your run directory) that are related to the anomaly forcing files (at least for the newer version):

user_datm.streams.txt.Anomaly.Forcing.Humidity
user_datm.streams.txt.Anomaly.Forcing.Longwave
user_datm.streams.txt.Anomaly.Forcing.Precip
user_datm.streams.txt.Anomaly.Forcing.Pressure
user_datm.streams.txt.Anomaly.Forcing.Shortwave
user_datm.streams.txt.Anomaly.Forcing.Temperature
user_datm.streams.txt.Anomaly.Forcing.Uwind
user_datm.streams.txt.Anomaly.Forcing.Vwind
user_nl_datm

I've attached those files as an example.
 

Attachments

  • user_datm.streams.txt.Anomaly.Forcing.Humidity.txt
    702 bytes · Views: 17
  • user_datm.streams.txt.Anomaly.Forcing.Longwave.txt
    702 bytes · Views: 8
  • user_datm.streams.txt.Anomaly.Forcing.Precip.txt
    698 bytes · Views: 7
  • user_datm.streams.txt.Anomaly.Forcing.Pressure.txt
    698 bytes · Views: 7
  • user_datm.streams.txt.Anomaly.Forcing.Shortwave.txt
    702 bytes · Views: 6
  • user_datm.streams.txt.Anomaly.Forcing.Temperature.txt
    700 bytes · Views: 8
  • user_datm.streams.txt.Anomaly.Forcing.Uwind.txt
    697 bytes · Views: 8
  • user_datm.streams.txt.Anomaly.Forcing.Vwind.txt
    697 bytes · Views: 9
  • user_nl_datm.txt
    1.1 KB · Views: 22
C

caufj

Jing Fu
New Member
oleson said:
@caufj ,there aren't any required modifications to user_nl_cpl related to anomaly forcing. You should have the following user_* files in your case directory (not your run directory) that are related to the anomaly forcing files (at least for the newer version):

user_datm.streams.txt.Anomaly.Forcing.Humidity
user_datm.streams.txt.Anomaly.Forcing.Longwave
user_datm.streams.txt.Anomaly.Forcing.Precip
user_datm.streams.txt.Anomaly.Forcing.Pressure
user_datm.streams.txt.Anomaly.Forcing.Shortwave
user_datm.streams.txt.Anomaly.Forcing.Temperature
user_datm.streams.txt.Anomaly.Forcing.Uwind
user_datm.streams.txt.Anomaly.Forcing.Vwind
user_nl_datm

I've attached those files as an example.
Click to expand...
Thank you for your kind reply.
Another question is where to find the source code dealing with anomaly forcing calculations? I only grep the initialization process in the atm2lndType.F90 file and want to know more about where the anomalies are added to the reference forcing.
In addition, in the source code of atm2lndType.F90, the humidity anomaly, for example, is assigned as 'af_shum_grc', but in your user stream file it is 'shum_af'. Doesn't it matter?
 
J

Joshua Rady

Joshua Rady
New Member
@oleson your anomaly forcing files including wind are worked for me once I converted them to netCDF5. The libraries must have changed recently.
 
O

oleson

Keith Oleson
CSEG and Liaisons
Staff member
@Joshua Rady , yes at some point we had to start converting the netCDF-4 input files. We'll convert these when we put them into the permanent directory, thanks.
 
erik

erik

Erik Kluzek
CSEG and Liaisons
Staff member
Note, that there are some notes about doing this with the new NUOPC coupler here:

github.com

Example, user_nl_datm_streams file for anomaly forcing for NUOPC coupler · Issue #1730 · ESCOMP/CTSM

We need an example user_nl_datm_streams file for anomaly forcing for the NUOPC coupler. @wwieder has a test case to base this off of here: /glade/work/wwieder/ctsm/ctsm5.1.dev054/cime/scripts/NEON_...
github.com github.com

The above notes from @oleson are for the older MCT coupler. The very latest CTSM is moving to the NUOPC coupler and the setup is a bit different between the two. Right now we still support the MCT coupler, but will be removing that support soon for the development version of the model.
 
C

caufj

Jing Fu
New Member
oleson said:
The anomaly forcing data has been updated (includes wind files) but not yet placed in the location referenced by the documentation. There is a least one issue (CTSM issue) associated with this process:

github.com

Update Anomaly forcing data and contrib script · Issue #1300 · ESCOMP/CTSM

@swensosc has updates to the ssp_anomaly_forcing_smooth in tools/contrib that also processes winds among other changes. The current script was used to create the data under $DIN_LOC_ROOT/tm/datm7/a...
github.com github.com

The data is currently at:

/glade/p/cgd/tss/people/oleson/anomaly_forcing

I personally have done one simulation with this data (quite some time ago however) and it appears to give reasonable/expected results The case directory is here:

/glade/work/oleson/release-clm5.0.30/cime/scripts/clm50_r-clm5.0.30_1deg_GSWP3V1_iso_SSP3-7_AnomalyF2

Regarding your second question, perhaps @swensosc can answer.
Click to expand...
Hi Keith,
could you please tell me how can I get access to the data at
/glade/p/cgd/tss/people/oleson/anomaly_forcing
Thanks a lot!
 
G

Gabriel.Hes

Hes
Member
Hi all,
I would like to know how the anomaly forcing dataset is obtained (/glade/p/cesmdata/cseg/inputdata/atm/datm7/anomaly_forcing/CMIP6-SSP3-7.0).Is the data an average of all CMIP6 GCMs or just a specific GCM? Thanks a lot
 
O

oleson

Keith Oleson
CSEG and Liaisons
Staff member
They were created from the set of CESM2 CMIP6 SSP3-7.0 simulations. Three ensemble members.
 
G

Gabriel.Hes

Hes
Member
Thank you!
Actually, I am using the SSP5-8.5 simulations but I assume they were generated the same way. Do you know what is the warming range (for 2100 ?) of the theses CMIP6 CESM2 ensembles used for the SSP5-8.5 forcing? As comparison, the warming range for the full CMIP6 runs given in IPCC AR6 is +4.4 [3.3 to 5.7] K.
 
O

oleson

Keith Oleson
CSEG and Liaisons
Staff member
Yes, the SSP5-8.5 anomaly forcing was generated the same way.
I don't know offhand what the warming range is. Over land only, for SSP5-8.5, you can look at these timeseries plots of TSA (2-m temperature) for each of the three ensemble members:



 
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