Simple Biosphere Model

In climate modelling, the simple biosphere model (SiB) is a model of the biosphere for use with atmospheric general circulation models (GCMs) that attempts to incorporate a biophysical realism in the formulation of the radiation balance and of energy at a level of appropriate sophistication to exist in the models GCMs

An interactive method of optimization was used to define a new group of morphological and physiological parameters to the vegetation. Micrometeorological measures including energy flows collected above of the Amazonian Forest’s dossal were used to validate and to calibrate the parameters of the SiB. The new group of parameters generated a better adjustment between the calculated latent and sensible heat flows and the observed ones. The values of the dossal conductance found in this work were smaller than those described in the literature, and it was evidenced that the stomatal response to the water vapor pressure deficit and to the leaf water potential plays an important role in the assessing of daily transpiration of the tropical forest.

The strategy adopted by the researchers in this model was to model the own vegetation allowing that the plants determine by itself its interaction with the atmosphere. The vegetation was separated in two different layers; the first one was composed by trees and bushes (higher plants) and the other one by grass and herbaceous plants (lower plants). The SiB model requires parameters of the morphological, physical and physiological plants properties. The model SiB has in its formulation seven prognostic variables of the physical state: two temperatures, two of storage of water in the plant, and three layers indicating the humidity of the soil.

An updated version is named Revised Simple Biosphere Model (SIB-2).