output question of CLM-DGVM

[zhaojc@fio_org_cn]

Dear Prof.

I run the CLM-DGVM with the code and data downloaded from the CLM3.5 website. GPP and NPP reached equilibrums after about 100 years run , with about 360 PgC/year and 180 PgC/year respectively. but RH still kept the increasing trend after 300 years run and the the value is just 100 PgC/year.
some person mentioned in this forum that CLM-DGVM need only 250 years to reach equilibrum, so I want to know if my run is reasonable as to its longer run time.
Is it because the soil carbon needs longer time, i.e. 1000 years, to reach its equilibrum that the RH still increased?
Another question is that in my simulation, negative NPP appears in some regions continued. but the userguide mentions that negative NPP would lead to death.

I will appreciate it if you can give me some advice!

 

[slevis]

Dear zhaojiechen,

We never evaluated the soil bgc part of the clm-dgvm, so I cannot answer your question about heterotrophic respiration.

I also do not have a good response about your negative NPP, other than to suggest that you diagnose this result further yourself. Eg, do areas with neg. NPP show decreasing vegetation cover or changing pft composition?

Sam Levis (not a Prof.!)