A
land surface model (Biosphere-Atmosphere Interaction Model Ver.2: BAIM2) can
estimate not only the energy fluxes, but also the carbon dioxide flux between
terrestrial ecosystems and the atmosphere. The photosynthesis processes for C3
and C4 plants are adopted in the model. The carbon storage of
vegetation is divided into five components (leaves, trunk, root, litter, and
soil), and the carbon exchanges among the components of vegetation and the
atmosphere are estimated in each time step of the on-line model integration.
The values of morphological parameters using in the model are derived from the
carbon storage values of the components, and the phenological changes of
vegetation are reproduced by the model. The BAIM2 was incorporated into a
spectral general circulation model, and was connected on-line to the atmospheric
model. Using this climate model, an experimental control time integration was
performed under the actual global vegetation condition. After the control time
integration, the vegetation types of Southeast Asia
were changed to the C4 grass, and the vegetation change impact
integration was performed. The results of the impact experiment were compared
with the results of the control. In the Indochina Peninsula
area, by the vegetation change from the tropical seasonal forest to the C4
grass, year mean values of the NPP generally increased, and those of the NEP also increased. On the other hand, in the
maritime continent area, by the change from the tropical rain forest to the C4
grass, the NPP values generally decreased, and the NEP
values also decreased. It was considered that the differences of phenological
changes of vegetation in these areas and the differences of climatic impact of
vegetation changes induced the different change phenomena of the carbon cycles.
There is a possibility that the influences of the vegetation changes
(deforestation) on the carbon cycles are different in the area where the
original vegetation types are different.
Author: K. Mabuchi and H. Kida (kmabuchi at mri-jma dot go dot jp)
Filesize: 30.75 Kb