Geography Reference
In-Depth Information
1.2.1 Influence of Physical Characteristics on Climate
Charney (
1975
) first explored the relationship between the change of albedo and
the drought in the Sahara region. Thereafter, there were a lot of researches on the
influence on regional climate (e.g., temperature and precipitation), which is
exerted by single parameter of physical characteristics of the land surface (e.g.,
albedo, roughness, leaf area index and soil moisture) (Shukla and Mintz
1982
;
Lambin and Geist
2006
). The change in the underlying landscape alters the energy
and moisture budgets of the land surface at regional scale, which in turn lead to the
changes in the fluxes of heat, water, and dynamics of the near-surface atmosphere
and influence the key thermodynamic and dynamic properties of the air, which is
of great importance to air convection (Brovkin et al.
2013
). The evidence to
support this statement comes from the sensitivity studies that explore the impacts
of change in characteristics of land surface (Wickham et al.
2012
).
There is another considerable evidence of the significance of land surface
processes generated through regional-scale perturbation experiments and resear-
ches on deforestation (Shukla et al.
1990
), desertification (Salvati and Bajocco
2011
) and land use changes. These researches all indicated LUCC contributed to
the large and statistically significant change in temperature, rainfall and other
variables at continental or regional scales.
First and foremost, some important researches on the sensitivity of climate to
the change of land surface evapotranspiration were performed by Davin and
Noblet-Ducoudré (
2010
), which provided significant evidence that the change of
the land surface evapotranspiration can lead to great changes in temperature and
precipitation. For example, deforestation will lead to the decrease of evapotrans-
piration, while the decrease of latent heat will increase the near-surface temper-
ature and lead to higher sensible heat flux (Davin and de Noblet-Ducoudré
2010
).
There is a high transpiration rate in the tropic rainforest, with the decrease of
transpiration rate due to the disappearance of the tropic rainforest may lead to
regional warming and drought in the future (Defries et al.
2002
). In addition, the
change in evapotranspiration also influences water content in the atmosphere, and
reduces the greenhouse effect and consequently reduces the temperature. While the
decrease of cloud covers will increase the solar radiation, and consequently
strengthen the temperature (Dessler
2010
). Therefore, due to the large number of
parameters, it is difficult to quantitatively compare the two feedbacks and there is
great uncertainty (Pachauri and Reisinger
2007
).
Land surface albedo is the fraction of solar energy (shortwave radiation)
reflected from land surface into space. It represents the reflecting power of the land
surface, and plays a key role in influencing the radiation balance and energy
balance of the land surface (Lynch et al.
1999
). The change of land surface albedo
