Table 1.

Comparison of measured wind speeds inside and above canyons; climate classification is made according to Köppen–Geiger Climate Classification System [52]; $U_o$ is ambient wind speed, $U_{o-m}$ mean ambient wind speed, $U_{o-p\%}$$p\%$ of ambient wind speeds, and similar naming method for wind speed inside canyon $U_i$, L/H ratio of street length L to building height H.

City/climate	Measurement period	AR	L/H	Ambient wind speed (m/s)	Ambient wind direction	Wind speed inside canyon (m/s)	Reference
Stafford/Maritime temperate (Cfb)	Mar.–Dec. 1997	0.59	–	$U_{o-m}=6.25U_{i-m}$	–	Total: $U_{i-m}=0.16U_{o-m}$	[53]
Kyoto/Warm temperate (Cfa)	–	1	–	$U_{o-m}=1.49U_{i-m}$	–	Total: $U_{i-m}=0.67U_{o-m}$	[41]
Watford/Maritime temperate (Cfb)	–	–	–	$U_{o-m}=1.59U_{i-m}$	–	Total: $U_{i-m}=0.63U_{o-m}$	[54]
Athens/Dry-summer (Csa)	Jul. 19–23, 2002	1.7	2.25	$U_{o-m}=3.4$ $U_{o-25\%}<2.1$ $U_{o-95\%}<6.6$	Perpendicular: 21% Parallel: 13% Oblique: 66%	Horizontal: $U_{i-50\%}<0.6$, $U_{i-95\%}<1.5$ Vertical: $U_{i-m}=0.34-0.46$	[55]
Goteborg/Maritime temperate (Cfb)	Jun. 2003–Aug. 2004	2.1	3.3	$U_{o-m}=1.8-2.5$	–	Total: $U_{i-m}\le 0.5$	[45]
Athens/Dry-summer (Csa)	Jul. 7–15, 1997	2.5	7.1	$U_{o-93\%}<5.0$ $U_{o-50\%}<2.0$	Perpendicular: 7% Parallel: 12% Oblique: 81%	Total: $U_{i-45\%}<0.3$, $U_{i-96\%}<1.0$ Horizontal: $U_{i-m}=0.35$ Vertical: $U_{i-m}=0.26$	[49]
Ghardaia/Arid (BWh)	Feb. 19–24, Sep. 6–13, 2005; Aug. 6–15, 2006	2.7–2.9	9.4–11.6	$U_{o-m}=1.0-3.0$	–	Total: $U_{i-m}=0.5-1.5$	[56]
Athens/Dry-summer (Csa)	Sep. 2001	3.3	1.7	$U_{o-(89\%-94\%)}<4.0$	Perpendicular:28% Parallel: 16% Oblique: 56%	Total: $U_{i-m}=1.0-2.0$	[25]
Tinos/Dry-summer (Csa)	Summer and winter	0.7–0.9	–	$U_o=9.0-16.0$	–	$U_{i-m}=1.0-6.5$	[26]
		2.0–4.0				$U_i<2.0$, $U_{i-m}\approx 1.0$