Geography Reference
In-Depth Information
concerned about the benefits of the Green for Grain project, it should be noted
whether such large-scale land cover changes will impact the regional climate. Will
it relieve the drought to some extent or make it more serious? Does it have effects
on energy balance of near surface? Returning cropland to forestry area or grassland
will continue in the next few decades to protect the ecological environment;
therefore, the contribution of land cover changes to the energy flux of near surface
becomes one of the significant issues (Kang 1985 ).
To quantify the effects of land cover changes on energy balance in the Loess
Plateau, it is essential for regional ecological environment construction. This study
simulates the spatial heterogeneity of land cover changes based on the Dynamics of
Land System (DLS) model, estimates the surface energy variation at a regional scale
based on the principle of energy balance and similarity theory of boundary layers with
the WRF model, and finally explores the response mechanism of the temporal and
spatial variation of surface energy on land cover changes. The results will provide the
scientific reference for the land use planning and climate change mitigation.
5.2.1 Data Source and Handling
5.2.1.1 Land Cover Data
Different communities have different land cover classification systems, and this
study applies the classification system of USGS with 24 types of land cover. First,
1 km land cover data in 2010 are extracted from the remote sensing images, and the
year 2010 is taken as the baseline year. Then two kinds of scenario, e.g., coordinated
environmental sustainability (CES) scenario, rapid economic growth (REG) sce-
nario, etc., are designed. The land cover data during 2010-2050 are simulated by
DLS model based on the land demand estimated under the two scenarios. Finally,
the 1 km resolution land cover data from 2010 to 2050 were resampled into 10 km
resolution data according to the requirement of the WRF model.
5.2.1.2 Forcing Data
The forcing data required in the WRF model, including wind field, surface air
temperature, longwave radiation, shortwave radiation, and so on, are derived from
the dataset of the fifth phase of the Climate Model Intercomparison Project
(CMIP5). CMIP5 consists of 29 global climate models, and the dataset of Geo-
physical Fluid Dynamics Laboratory CM3 (GFDL-CM3) model are adopted in this
study. It incorporates an atmospheric chemistry model within the fully interactive
framework of the atmosphere, ocean, land, and sea ice components, and has four
Representative Concentration Pathways (RCPs) scenarios such as RCP2.6,
RCP4.5, RCP6.0, and RCP8.5. This study analyzed the energy balance under the
RCP6.0
scenario,
the
CO 2
concentration
under
this
scenario
rank
in
the
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