Geography Reference
In-Depth Information
(Table
6.4
). Under each scenario, the demand of urban land for whole Wuhan
Metropolitan is 819,784 hm
2
, while the demand of farmland in the whole is
25,741,94 hm
2
.
6.3.3.2 Scenario Simulation of Urban Land Expansion for Wuhan
Metropolitan
According to asynchronous evolution intervals that set by urban land expansion
scenario for Wuhan Metropolitan and combing transform rules for each partition
and global stopping conditions which were determined by socioeconomic condi-
tions and natural resource endowments in Wuhan Metropolitan, the Partitioned and
Asynchronous Cellular Automata Model can be employed to carry out urban land
expansion patterns under each scenario in Wuhan Metropolitan (Fig.
6.17
). As
could be seen, spatial patterns of urban land use results in very similar results
under baseline scenario and centralized scenario for Wuhan Metropolitan. The
difference lies in that the speed of urban land expansion in big cities and small
cities are different but both developed under baseline scenario. However, under
centralized urbanization scenario, the speed of urban land use expansion for big
cities and small cities has a very significant variation. Urban land use expansion in
Wuhan and its surrounding areas is very rapid, but urban land use of other areas in
Wuhan Metropolitan expanded very slowly. Compared with former two scenarios,
urban land use expansion law of Wuhan Metropolitan is distinctly different in
decentralized urbanization scenario: Wuhan and its surrounding areas urban land
expansion are very small although urban land expansion is obvious in corre-
sponding small urban areas.
The underlying surface of WRF model is classified based on classification
criteria of USGS data, while Land Use/Cover in urban land expansion simulation
was divided into five categories: farmland, forestland, grassland, water bodies, and
built-up land. Therefore, the simulation results cannot be directly used as under-
lying surface input data. Based on original underlying surface data of WRF model,
urban land expansion simulation results are converted to raster datasets which have
same scale with underlying surface data of WRF model by spatial analysis tools in
ArcGIS. Grid data in original underlying surface data are then displaced by urban
land use type in corresponding grid in processed urban land expansion simulation
results. The obtained new underlying surface data contains urban land expansion
in Wuhan Metropolitan under various scenarios (Fig.
6.18
).
6.3.3.3 Scenario Analysis of Urban land Expansion on Climate
Change Impacts
We kept boundary conditions and other initial field of WRF model constant, and
substituted Wuhan Metropolitan's underlying surface data under different sce-
narios for WRF model. Regional climate change under different scenarios in
