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Figure 25.7 Daily variations in near surface (a) air temperature, (b) specific humidity deficit, and (c) wind speed measured
over a small grassland clearing and undisturbed tropical rainforest near Manaus in Amazonia. (Adapted from Bastable
et al ., 1993.) (d) Measured change in near-surface temperature in Japanese cities between 1907 and 2007 associated with
the urban heat island. (Adapted from Wikimedia Commons, available at http://commons.wikimedia.org.)
2.
Effect of imposed land-cover change on regional-scale climate
The physical basis for expecting modification of regional-scale and perhaps
global-scale climate when there is extensive imposed land-cover change is that
the key properties of the land surface that determine surface exchanges with the
overlying atmosphere such as albedo, surface roughness and vegetation-related
moisture stores and controls will be altered. Since these key properties control
the influence of the land surface on the overlying atmosphere, it is plausible that
there will be some impact on weather and climate if the spatial scale of imposed
land-cover change is sufficiently large. Presumably the impact will be greatest
for  dramatic land-use change, such as from forest to agricultural cover or
pastureland.
Collecting 'before' and 'after' observations of large-scale land-cover change is
problematic so most of the evidence for regional and global-scale modification
of  climate in response to large-scale land-use change comes from model studies
using mesoscale meteorological models and GCMs. There is a huge body of
scientific literature in this area of research; example results from a study using a
mesoscale model are shown in Fig. 25.8 and using a GCM in Fig. 25.9. Narisma and
Pitman (2003) used the fifth generation Pennsylvania State University-National
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