Geography Reference
In-Depth Information
outflow activity. Shepherd also showed that expansion of future urban land might
result in a more expensive area of rainfall (Shepherd et al.
2010
). Urbanization
would increase the emission of atmospheric pollutants, cause the heat island effect,
and lead to land use change. The volatile air layer can lead to thermal convection
easily due to UHL effect, which can increase thermal convection and convective
precipitation. Moreover, buildings of different heights can not only cause
mechanical turbulence, but also hinder the moving slow precipitation system, thus
leading to increase of precipitation. At the same time, there are intensive human
activities in urban regions, which lead to the emission of a large amount of green-
house gases, aerosol, and other particulate matters. On one hand, these materials
increase the condensation nucleus for precipitation; on the other hand, these
materials intensify the UHL effect in urban regions. Under the condition of sufficient
moisture, there will more precipitation due to increased condensation nucleus above
the municipal areas and relatively high underlying surface temperature, which may
account for the increase of precipitation in this region in summer.
6.1.3 Concluding Remarks on Future Urbanization and its
Climate Effects in the Great Beijing Area
Urban climate change results from the interaction between human activities and
local climate change in essence. The change of underlying surface properties and
human-induced heat emission will lead to the difference between urban and rural
temperature, which will further change local climate forcing field and conse-
quently lead to the redistribution of climate factors, such as the wind, cloud, and
precipitation. This study investigated the contribution of urban land use change to
the change of temperature and precipitation in Great Beijing area during
2030-2040 with the WRF model based on the latest actual urban land cover data
from 1995 to 2005.
The impact of urbanization on regional climate change is a very complex and
challenging problem and it is necessary to carry out more in-depth research since
there are still some uncertainties in the current research. For example, more efforts
should be made to comprehensively investigate the contribution of urbanization to
the change in annual temperature and precipitation, extreme climate, latent heat
flux at land surface, wave flux at ground surface. Meanwhile, it is necessary to
carry out further research on how to quantitatively measure the inner link between
urban development and climate factors and how this inner link will change when
climate factors change. Urban area in this region would increase continuously, and
urban expansion leads to continual increase of local temperature and will make
precipitation in summer show an increasing trend during 2030-2040.
The results of this study indicated that the anthropogenic land cover change has
significant impacts on regional climate in the Great Beijing area, which can provide
scientific reference for optimizing land use management and planning to mitigate
and adapt to regional climate change in the future. For example, government can
