Environmental Engineering Reference
In-Depth Information
TABLE 3.5
Changing Local Climate (on a Clear Mid-July, Mid-Morning Period
in Phoenix—Same Time as Landsat Overfly Times)
a
Surface
Temperature (°F)
Parameter Changed
% Shade on surface area
25
113.5
50
102.9
75
90.1
100
74.3
% Wetting of surface
30
107.9
50
102.2
70
98.1
% Albedo
10
118.8
15
116.2
20
113.7
30
108.7
Surface type and aerodynamic roughness around the site
b
Irrigated smooth
95.0
Irrigated rough
77.5
Desert smooth
107.4
Desert rough
98.6
Asphalt smooth
124.5
Asphalt rough
104.9
Water smooth
93.9
Water rough
77.0
a
Values from Brazel and Howard
14
using equilibrium surface temperature energy
budget model.
b
Roughness is aerodynamic roughness ranging from smooth at close to 0.0 in.;
rough = 3.9 in.
TABLE 3.6
Urban Canyon Effects: Height/Width (H/W) of Buildings, and Street Temperature
Excess
/Reductions (°F)
Nighttime
Daytime
H/W
Observed Temp. Excess
a
Model Temp. Excess
b
Temp. Reduction (obs)
0.25
+0.9
0.5
1-1.8
+1.8
−4.5 (−10.0 at well ventilatedsite)
(in Tempe, Arizona)
1.0
1-1.8
+3.6
−9.0 (Negev Desert Study, Israel
c
)
2.0
1-1.8
+5.4
−7.9 (Tempe, Arizona)
3.0
+6.3
5.0
+8.1
10.0
+9.9
a
Modeled nighttime data after Oke.
13
b
Studies in Tempe (difference is street canyon minus ground site outside the canyon).
c
After Pearlmutter
16
(difference is street canyon minus roof top).
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