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(a)
6
Figure 7.7 Difference
between urban and non-
urban (a) temperature,
(b) latent heat flux, and
(c) sensible heat flux.
Comparison for
Sacramento, California, USA
(S91, S) where the urban (u)
is a residential
neighborhood with irrigated
vegetation and a dry (d)
unirrigated long grass area
and a wet (w) irrigated sod
farm; Tucson, Arizona
(T90, T) where the urban (u)
area is a residential
neighborhood with some
irrigated vegetation and the
natural desert (d); and
Vancouver, British Columbia
(V92, V) which is a
residential neighborhood (u)
with vegetation that was not
being irrigated during this
period because of drought
but would typically be an
agricultural field of soy
beans (r).
S91u-d
S91u-w
T90u-d
T92u-r
5
4
3
2
1
0
-1
-2
(b)
150
100
T
50
S d
0
-50
V
-100
V92u-r
S w
-150
(c)
150
S w
100
V
50
0
-50
T
-100
-150
S d
-200
V92u-r
-250
0
4
8
12
16
20
To illustrate this point, results from a study by Oke and Grimmond ( 2002 )
are presented (Figure 7.7 ). While conventional wisdom states that urban areas
are warmer than their rural surroundings, the urban-rural differences may in
fact reverse, depending on the land cover/use of the region that surrounds the
urban area (Figure 7.7 ). For example, in Sacramento, California, a naturally
arid area, extensive agricultural irrigation results in greater contrasts between
rural areas than between rural and urban areas. Depending on the rural
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