Question about assessing equilibrium for a regional simulation in CLM5.0-BGC after AD spinup

[chenyihui]

Dear All,

I am running a regional simulation with CLM5.0-BGC. My study area is approximately 25–45°N, 70–105°E. I have completed a 300-year AD-spinup.

Now I am trying to determine whether my ADspinup has reached equilibrium. I found that the SpinupStability.ncl script is designed for three specific configurations: Global, Arctic, and Single Point (SPT). It does not seem to be suitable for my regional domain.

For a regional simulation like mine, what is the recommended approach to assess equilibrium? Should I manually modify the script to mask my study area, or is there a better way?

I would greatly appreciate any suggest,

Thank you!

 

[oleson]

Looking at the spinup script, the only aspect that appears to be different when specifying Arctic is this:

if (region .eq. "Arctic") then
resc@mpLimitMode = "LatLon"
resc@mpMinLatF = 50.
resc@mpMaxLatF = 85.
resc@mpMinLonF = -180.
resc@mpMaxLonF = -95.
resc@gsnAddCyclic = False
resc@mpProjection = "CylindricalEquidistant"
end if

This simply sets the lat/lon bounds for the plotting routines when generating the TOTECOSYSC Disequil Yr contour plots.
So it seems like you could adjust these for your regions.

On the other hand, the equilibrium threshould settings are specfied for global simulations:

glob_thresh_totecosysc = 0.02 ; global threshold for TOTECOSYSC equilibrium (delta PgC / yr)
glob_thresh_totsomc = 0.02 ; global threshold for TOTSOMC equilibrium (delta PgC / yr)
glob_thresh_totvegc = 0.02 ; global threshold for TOTVEGC equilibrium (delta PgC / yr)
glob_thresh_tlai = 0.02 ; global threshold for TLAI equilibrium (delta m2/m2 / yr)
glob_thresh_gpp = 0.02 ; global threshold for GPP equilibrium (delta PgC / yr)
glob_thresh_tws = 0.001 ; global threshold for TWS equilibrium (delta m / yr)
glob_thresh_h2osno = 1.0 ; global threshold for H2OSNO equilibrium (delta mm / yr)
glob_thresh_area = 3.0 ; global threshold percent area with TOTECOSYSC disequilibrium gt 1 g C/m2/yr
totecosysc_thresh = 1.0 ; disequilibrium threshold for individual gridcells (gC/m2/yr)

and you may want to or have to adjust these based on your specific region and spinup objectives.

 

[chenyihui]

Looking at the spinup script, the only aspect that appears to be different when specifying Arctic is this:

if (region .eq. "Arctic") then
resc@mpLimitMode = "LatLon"
resc@mpMinLatF = 50.
resc@mpMaxLatF = 85.
resc@mpMinLonF = -180.
resc@mpMaxLonF = -95.
resc@gsnAddCyclic = False
resc@mpProjection = "CylindricalEquidistant"
end if

This simply sets the lat/lon bounds for the plotting routines when generating the TOTECOSYSC Disequil Yr contour plots.
So it seems like you could adjust these for your regions.

On the other hand, the equilibrium threshould settings are specfied for global simulations:

glob_thresh_totecosysc = 0.02 ; global threshold for TOTECOSYSC equilibrium (delta PgC / yr)
glob_thresh_totsomc = 0.02 ; global threshold for TOTSOMC equilibrium (delta PgC / yr)
glob_thresh_totvegc = 0.02 ; global threshold for TOTVEGC equilibrium (delta PgC / yr)
glob_thresh_tlai = 0.02 ; global threshold for TLAI equilibrium (delta m2/m2 / yr)
glob_thresh_gpp = 0.02 ; global threshold for GPP equilibrium (delta PgC / yr)
glob_thresh_tws = 0.001 ; global threshold for TWS equilibrium (delta m / yr)
glob_thresh_h2osno = 1.0 ; global threshold for H2OSNO equilibrium (delta mm / yr)
glob_thresh_area = 3.0 ; global threshold percent area with TOTECOSYSC disequilibrium gt 1 g C/m2/yr
totecosysc_thresh = 1.0 ; disequilibrium threshold for individual gridcells (gC/m2/yr)

and you may want to or have to adjust these based on your specific region and spinup objectives.

Thank you!