Geography Reference
In-Depth Information
Table 5.6 Parameterization
scheme of physical processes
in the WRF model
Classification of schemes
Scheme option
Physics parameterization scheme
WSM 3-class simple ice
Cumulus parameterization scheme
Grell-Devenyi ensemble
Boundary layer process scheme
YSU
Radiation scheme
CAM 3 radiation
Land surface process scheme
Noah land surface model
proportion of grassland accounting for the total area of Northwest China has
decreased from about 36 % in 1995 to 31 % in 2008, and most of grassland
degraded into barren land and croplands. The intensive grassland degradation has
resulted in more and more acute contradiction between the human and nature,
economic development, and eco-environmental conservation.
5.3.1.2 Data Resource
The data required in this study are similar to the ones in the second case study, and
have the same derivation. The differences are that the data in this case study are
from 2010 to 2040, so we will not illustrate them again over here.
5.3.1.3 Test Design
The parameterization scheme of physical processes in the WRF model in this study
is as follows (Table
5.6
). It mainly includes the WSM 3-Class simple ice physical
scheme, ensemble cumulus convection schemes of Grell-Devenyi ensemble, YSU,
CAM3 radiation schemes, and consolidated NOAH land surface parameterization
scheme (Snyder et al.
2004
).
In this study, two numerical simulation tests, including the control test and
sensitivity test, are designed and performed with the same horizontal resolution
and parameterization scheme in order to analyze the effects of grassland degra-
dation on the regional climate more accurately. The control test is designed as a
reference case, which uses the land cover data of 2010 and assumes that the land
cover will not change during 2010-2040. On contrary, the sensitivity test supposes
that the land cover change with time, therefore, it will apply the simulated land
cover from 2010 to 2040, in which part of grassland converted into bare land,
croplands, or urban area. The center of the simulated area is located at 3753
0
N,
1091
0
E with two standard parallels of 39 N and 35 N, including 27 grid points
in the east-west direction, and 48 grid points in the north-south direction. The
simulation period is 30 years from January 1st, 2010 to December 31st, 2040.
