Geography Reference
In-Depth Information
1.4.2 Urbanization and Its Regional Climate Effect
Urbanization is an extreme way in which human activities alter the underlying
surface properties and influence the local climate. The urban heat island effect due
to urbanization is an extreme example of the influence of LUCC on regional
climate. The urbanization has contributed to 50 % of the increase of land surface
temperature in the USA since 1950 (Stone
2009
). The city differs greatly from the
natural land cover. The widespread impervious surface and the roof and wall of
buildings, etc. in the cities, all influence the energy flux, circulation of water and
other materials. They can reduce the evaporation from land surface, make it dif-
ficult to eliminate land surface heat, and consequently lead to the increase of land
surface temperature (Li et al.
2011
). Besides, man-made heat emission and
decrease of vegetation coverage also contribute to the increase of land surface
temperature. In some cities, local people have grown a lot of plants or painted the
roofs write so as to reduce the reflectivity of the urban land surface and alleviate
the urban heat island effect (Wong and Lau
2013
).
Considerable progress has been made in the development of urban climate
models which is able to predict/simulate meteorological conditions from regional
to building scales. The results of current qualitative researches indicate that the
lowest daily air temperature increases more than the highest daily air temperature,
which leads to the decrease of daily temperature difference (Murata et al.
2012
).
Besides, the Bowen ratio and canopy temperature of cities will increase with the
proportion of impervious surface (Ge et al.
2007
). In addition, previous researches
have mainly focused on the urban heat island effect of big cities.
1.5 Summary
This chapter reviews the advances in the researches on the influence of LUCC on
surface climate, including how LUCC influences the surface climate, the relevant
simulations and their improvement and the application in case studies, the main
findings can be summarized as follows. A large number of researches have doc-
umented the important effects of LUCC on regional climate system. Besides,
biogeophysical and biogeochemical effects of large-scale LUCC have also been
studied. But the relevant researches on their mechanism have generally studied
biogeophysical and biogeochemical effects separately. It is the main means of the
research on the effects of land use changes on the climate to carry out numerical
simulation with a series of climate models of different complexities. The regional
climate models have higher resolution and can reflect the climatic characteristics
caused by local forcing, and have been widely used in the research on some
