DALEC - PLM

DALEC (Data Assimilation Linked Ecosystem Carbon) represents the C cycle with a simple box model of pools connected via fluxes. There are five pools: C content of foliage (Cf); woody stems and coarse roots (Cw) and fine roots (Cr); and of fresh leaf and fine root litter (Clitter) and soil organic matter (SOM) plus WD (CSOM/WD). 	The fluxes among pools are based on the following assumptions:<ol>

All C fixed during a day is either expended in autotrophic respiration or else allocated to one of three plant tissue pools – foliage, wood, or fine roots.

Autotrophic respiration is a fixed fraction of total photosynthetic fixation, and it is not directly temperature sensitive.

Plant allocation and litterfall are donor-controlled functions with no direct environmental influence and constant rate parameters.

Soil transformations are sensitive to temperature, with a Q10 of 2.0. Otherwise, the only environmental forcing in the C model is on GPP, via solar radiation, air temperature, and soil moisture.

All C losses are via mineralization; there is no dissolved loss term.

The aggregated canopy model (ACM) of photosynthesis (Williams et al., 1997) provides the forecast estimate of daily C inputs to the system. The ACM is a big-leaf, daily time step model that estimates GPP as a function of LAI, foliar nitrogen, total daily irradiance, maximum and minimum daily temperature, day length, atmospheric CO2 concentration, soil–plant water potential, and total soil–plant hydraulic resistance. The model has 10 parameters.

Related Publications
Williams, M.; Schwarz, P.A.; Law, B.E.; Irvine, J. and Kurpius, M.R. (2005). An improved analysis of forest carbon assimilation using data assimilation. Global Change Biology 11: 89-105.

Originally submitted to PLaSMo on 2010-11-02 10:27:31

DALEC - PLM_23

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