bpbond
commented
8 years ago Hi Laurence,
See the "Biome BGC version 4.2: Theoretical Framework of Biome-BGC" document available at http://www.ntsg.umt.edu/sites/ntsg.umt.edu/files/project/biome-bgc/Golinkoff_BiomeBGCv4.2_TheoreticalBasis_1_18_10.pdf, in particular pp. 45-. It says there that
The maximum rate constants for decomposition and biomass loss through heterotrophic respiration (HR) are all defined as constants in BBGC and were defined based on a literature review of C14 decomposition studies by Thornton (1998).
I don't have access to this reference (Peter Thornton's Ph.D. thesis) but the citation is
Thornton, P. E. 1998. Regional ecosystem simulation: combining surface- and satellite-based observations to study linkages between terrestrial energy and mass budgets. Ph.D. University of Montana, Missoula, MT.
I don't have any more information than this. (Your example of an adjusted rate of 0.175/day does seem high, though.)
Ben
Hello,
I am new to Biome-BGC and particularly interested in decomposition. I understand that there are 3 litter pools and 4 soil OM pools sorting OM by their recalcitrant levels. I am reading through the codes and found that the base decomposition rates (1/day) seems extremely high, e.g., 0.7 (day-1) for labile litter pool. Although this rate would be adjusted by soil temperature and moisture (let say t_scalar = 0.5 and w_scaler = 0.5), the adjusted decay rate 0.7_0.5_0.5 = 0.175 (day-1) is still very high. Litter decay rate from litter bags experiments is about 0.038 (day-1). The decay rate in the model is almost five times higher than the observed. Are these base decomposition rate constants mean to be calibrated or adjusted when use? Do you have any references for the current base decomposition rate constants? Thanks.
Laurence