Geography Reference
In-Depth Information
The Great Beijing area developed quickly with high land use intensity, especially the
large-scale science and technology parks, economic zones, industrial parks, and other
new development zones. Thus the conflict between rapid city growth and water and
soil resources has become increasingly pronounced.
6.1.1.2 Simulation Scheme
This study simulates the climate change in the Great Beijing area during
2030-2040 based on the control and sensitivity tests with WRF model. Two
simulation tests are conducted for summer (June-August) during 2030-2040
(Table
6.1
) under the same condition except the underlying surface in order to
indicate the impact of urbanization on temperature and precipitation. First, the
underlying surface data of 1992-1993 in WRF model is replaced since it cannot
exactly reflect the land surface condition after 2000. The land cover data in 2010
are used as the underlying surface data for the control test, and the land cover data
in 2030 predicted on the basis of the trend of social-economic simulation is used
for the sensitivity test. The simulation results of the control test and sensitivity test
are then compared, and the effects of urbanization on summer temperature and
precipitation are finally examined. The effects of future urban expansion on surface
climate can be explained with E
i
.
E
i
ΒΌ R
i
r
i
where i refers to the precipitation and temperature; E
i
is the effect of the future
urbanization on the climate; R
i
is the result of the simulation with the predicted
underlying surface, and r
i
is the result of the simulation with the baseline under-
lying surface.
The parameterization schemes in this study are listed in Table
6.2
. The Grell-
Devenyi ensemble scheme was adopted in the cumulus parameterization scheme,
with YSU being the boundary layer process scheme, and the CAM scheme being
both long-wave radiation and shortwave radiation scheme, while the land surface
process scheme was the Noah land surface model. The boundary buffer was set to
be four layers of grid points, and the relaxation scheme was adopted in the
boundary conditions. The time interval of the model integration was set to be
5 min, and that of the radiation process and cumulus convection was 30 and 5 min,
respectively. There were 27 layers in the vertical direction and the atmospheric
pressure at the top layer was 50 hPa.
The lateral boundary forcing data was from the National Centers for Envi-
ronmental Predictions (NCEP) operational Global Final (FNL) Analyses (NCEP/
FNL) and was updated every 6 h. The dataset was established on the basis of the
assimilation of almost all kinds of observational data (e.g., remote sensing data and
ground-based observation data) with a spatial resolution of 1 9 1 gird and a
vertical height of 27 layers, and it has been updated to now since July, 1999.
Compared with dataset of NCEP I, NCEP II, and EAR40, the NCEP/FNL not only
