Geography Reference
In-Depth Information
5.1.2 Impacts of Afforestation on the Regional Surface
Climate
The simulation results in 2010 are finally obtained under the scenarios of DB, DN,
EB, and EN as well as BL.
5.1.2.1 Effects on the Annual Average Temperature
The simulation results showed that there were significant effects of the vegetation
change on the annual average temperature in Jiangxi Province. Among the results
under the four hypothetical extreme scenarios, there were overall cooling effects
under the scenarios of DB and DN, while warming effects under the scenarios of
EB and EN (Fig.
5.2
). The statistics indicates that the deciduous broadleaf
expansion under the scenario of DB will make the annual average temperature
decrease by 0.08 C. This cooling effect will mainly happen in the southern part of
Jiangxi Province. For some area there, the annual average temperature will even
decline by more than 0.2 C. By comparison, the expansion of deciduous nee-
dleleaf forests under the scenario of DN only shows slight cooling effects, it is
notable that the cooling effects also mainly happen in the southern part of Jiangxi
Province, but are not as significant as that under the scenario of DB. The results
under the scenarios of DN indicate there are some warming effects in the areas
near the northern and western boundary of Jiangxi Province, while the overall
effects of the expansion of deciduous needleleaf forests make the annual average
temperature decrease by 0.02 C under the scenario of DN.
The spatial pattern of the warming effects under the scenario of EB is consistent
with the pattern of forests in Jiangxi Province, and the evergreen broadleaf
expansion will make the annual average temperature increase by 0.03 C
(Fig.
5.2
). The annual average temperature under the scenario of EN will increase
by 0.01 C more than that under the scenario of BL. In summary, the deciduous
forest plays a positive role in decreasing the annual average temperature while
evergreen forest contributes to the increase of annual average temperature, and the
effect of needleleaf forest expansion on annual average temperature is much more
significant than that of broadleaf forest. This may be due to the differences between
the thermal properties of the deciduous and evergreen forests.
5.1.2.2 Effects on the Annual Average Precipitation
The expansion of deciduous forests leads to significant change of the spatial
pattern of the annual average precipitation in Jiangxi Province regardless of the
scenarios. The simulation results showed that the expansion of deciduous broad-
leaf forests will make the annual average precipitation in the southeast part of
Jiangxi Province decrease by more than 400 mm (Fig.
5.3
). Besides, the annual
