I created a custom 0.1° regional case for China（CESM2.2.0）. The model was successfully configured and runs normally after replacing the default input datasets with China-specific atmospheric forcing data, PCT_NAT_PFT data, and soil datasets.
I am currently in the Accelerated Decomposition (AD) spinup phase and have completed 53 years of accelerated spinup.
In the attached figures, the left panel shows the NEP (Net Ecosystem Production) spatial pattern during the early stage of AD spinup (approximately years 20–30). At this stage, the spatial distribution appears reasonable and generally reflects the expected NEP pattern across China.
The right panel shows the NEP spatial pattern during the later stage of AD spinup (approximately years 40–50), after the deep soil carbon pools have become relatively stable. At this point, the NEP distribution appears much less realistic. I noticed that regions that originally had relatively low NEP values (the cyan-colored areas in the early-stage figure) show substantially higher NEP values later in the spinup. In contrast, the southeastern region, which originally had the highest NEP values, does not increase as rapidly as other regions, resulting in a much flatter and less realistic spatial pattern.
My questions are:
Any suggestions or insights would be greatly appreciated.
I am currently in the Accelerated Decomposition (AD) spinup phase and have completed 53 years of accelerated spinup.
In the attached figures, the left panel shows the NEP (Net Ecosystem Production) spatial pattern during the early stage of AD spinup (approximately years 20–30). At this stage, the spatial distribution appears reasonable and generally reflects the expected NEP pattern across China.
The right panel shows the NEP spatial pattern during the later stage of AD spinup (approximately years 40–50), after the deep soil carbon pools have become relatively stable. At this point, the NEP distribution appears much less realistic. I noticed that regions that originally had relatively low NEP values (the cyan-colored areas in the early-stage figure) show substantially higher NEP values later in the spinup. In contrast, the southeastern region, which originally had the highest NEP values, does not increase as rapidly as other regions, resulting in a much flatter and less realistic spatial pattern.
My questions are:
- Is this behavior expected during the AD spinup phase of CLM5/CESM?
- Can the stabilization of deep soil carbon pools and the accelerated decomposition mechanism alter the spatial pattern of NEP in this way?
- Should I continue running the AD spinup, or does this behavior suggest a potential issue with my setup or input data?
- Is it normal for the NEP spatial pattern during the late AD spinup phase to deviate substantially from the expected present-day pattern? Does the realistic spatial pattern only recover after switching to the normal (non-accelerated) spinup phase? If so, approximately how many years of normal spinup are typically required before the model reaches a realistic state? Since my primary interests are vegetation (especially forest) NEP, as well as sensible heat flux, latent heat flux, and albedo, what would be the minimum recommended duration of normal spinup before beginning the actual simulation and analysis?
Any suggestions or insights would be greatly appreciated.
