Geography Reference
In-Depth Information
well as irrational decision making process. The LUCD model describes a com-
bined and complex system composed of social economic, ecosystem components,
and decision making process and consequences. It provides a consistent and
comprehensive framework of land use change modeling and emphasis on how the
models work together. By introducing Agro-ecological zone (AEZ) based on the
simulation results of RCMs, the LUCD model is compatible with RCMs and
constitutes an iterative simulation system of LUCC and climate changes.
2.1.1 Land Use Change Dynamics Model
2.1.1.1 Model Structure
LUCD model constitutes of three modules, namely economic module, vegetation
change module, and agent-based module. The economic module calculates the
land demand for all economic activities maximizing economic utility of land uses.
The vegetation change module provides the probability of vegetation change
driven by climate changes. And the agent-based module identifies that if the land
demand and vegetation change can be realized and provides the land use change
simulation results, which are the underlying surfaces needed by RCM. To feed the
LUCD model results into RCMs, the land use system applied in the LUCD model
should be consistent with the underlying surfaces used in RCMs (Fig.
2.1
). By
iteratively using the output of one model as the input of another, the LUCD model
is compatible with RCMs. In Fig.
2.1
, the dotted lines show the data transmission
between the LUCD model and RCMs, while the solid lines stand for the flow of
information in the LUCD model. The LUCD model provides the simulated land
use for RCMs as underlying surface data, then RCMs can simulate the climate
change resulted from the land use change. The results of climate change simulated
by RCMs are further imported into the LUCD model, affecting land use change.
The economic module estimates the land use change demand driven by human
activity. The current condition of land uses are introduced into this module as one
of the limitations of economic activities as well as land use decisions. The equi-
librium of markets determines the commodity supply and in turn influences the
land use demand. Combining the land use demand, the limited amount of land as
well as the current land use status, the land use change demand is obtained. The
vegetation change module describes the possible vegetation change driven by
climate change. The AEZ is the key concept that links the climate change and
vegetation change and helps to couple human activity with climate change. The
climate change leads to change of AEZs, which determines the growth of vege-
tation (Stehfest et al.
2007
). Consequently, the climate change affects not only the
evolution of natural vegetation but also the human activities including planting and
breeding. By overlying the AEZs on the current vegetation pattern, the suitability
of vegetation change can be evaluated. The agent-based module describes the
procedure of land use decision coupled with the land use change demand and
