CESM2 single forcing large ensemble initial files

[shrestha]

Hi,

I’m using CESM2 Single Forcing Large Ensemble for my work. I had a few questions related to the dataset:

1. The ESG archive doesn’t have the datafile for ensemble member *xAER.004* for the 1920 to 2014 period. Was there an error with that particular ensemble member or was it just missed during the uploading process?

1. To my understanding, the BMB single forcing experiment uses a smoothed biomass burning (SMBB) file. I’m trying to do a comparative analysis between the 15 member BMB experiment and the corresponding 15 “full forcing” members from CESM2 LENS. I’m locating these corresponding “full forcing” files through the “initial_file” attribute in the BMB files that provide the piControl file it was initialized from. But almost half of these BMB files have even-numbered piControl files which I understand corresponds to members that use the original CMIP6 BMB files. For eg. The file

b.e21.B1850cmip6.f09_g17.CESM2-SF-BMB.004.cam.h0.PRECT.200001-201412.nc

has the following attribute:

initial_file = "b.e21.B1850.f09_g17.CMIP6-piControl.001.cam.i.1061-01-01-00000.nc";

 

[islas]

Hi Sisam,

Indeed, it seems to be a mistake that the xAER.004 simulations are not uploaded to ESG. Hopefully someone else who is monitoring this forum could chime in on that (@strandwg?). The data is available locally on glade if you have access there.

For your second question, the single forcing runs were start from the same date as the "macro" simulations of LENS2 so that they were all started from initial conditions that were different. Since only 10 of the macro simulations used the smoothed biomass burning simulations, there are some of them that start from the same date as runs that don't use the smoothed biomass burning emissions. However, by the late 20th century/early 21st century when the biomass burning is actually different, we expect that evidence of initial condition memory would be hard to find. Given that it can likely be assumed that there is very little impact on initial condition member, it may make more sense to just compare with the 50 SMBB members from LENS2, despite their differing initial conditions. But if you really do want to do a comparison with members from the same start date, I'm afraid that this will only really work up until the 1970's due to the differing biomass burning emissions after that.

Isla

 

[shrestha]

Thank you for the clarification! Currently I'm only looking at the 15 members for the comparative analysis. But an ensemble average across the 50 SMBB members would make sense for my work. I'll check the website for an update on the *xAAER004* ensemble member, thank you.

 

[strandwg]

Hi Sisam,

Indeed, it seems to be a mistake that the xAER.004 simulations are not uploaded to ESG. Hopefully someone else who is monitoring this forum could chime in on that (@strandwg?). The data is available locally on glade if you have access there.

For your second question, the single forcing runs were start from the same date as the "macro" simulations of LENS2 so that they were all started from initial conditions that were different. Since only 10 of the macro simulations used the smoothed biomass burning simulations, there are some of them that start from the same date as runs that don't use the smoothed biomass burning emissions. However, by the late 20th century/early 21st century when the biomass burning is actually different, we expect that evidence of initial condition memory would be hard to find. Given that it can likely be assumed that there is very little impact on initial condition member, it may make more sense to just compare with the 50 SMBB members from LENS2, despite their differing initial conditions. But if you really do want to do a comparison with members from the same start date, I'm afraid that this will only really work up until the 1970's due to the differing biomass burning emissions after that.

Isla

The data from the xAER.004 case will be added to the CESM2-SF collection within the next week.

 

[shrestha]

Thank you!

 

[tking]

Hi Sisam, The xAER.004 case has been added to the collection.

 

[shrestha]

Thank you!