Fine Scale Meteorology & Air Quality Models - School of Architecture ...

ASI2_Lecture 3_7/12/2011
Potential exposure assessment application:
Theory- Pollution retention in urban canyons
Courtesy of J. Richmond-Bryant
U
U
WIND
D
l
WIND
D
W
• H = Uτ/D = f(UD/ν, k 0.5 /U, l/D, D/W)
= f(Re, turbulence intensity, shape)
o H = nondimensional residence time of pollutant in canyon
o τ = residence time
o k = turbulence kinetic energy of the wind
o ν = kinematic viscosity
o Re = Reynolds number
• Based on dimensional analysis and derived from the equation
of scalar flux transport (Humphries & Vincent 1976)
ASI 2: URBAN CLIMATE AND AIR POLLUTION School of Architecture, The Chinese University of Hong Kong, Hong Kong, 7-8 Dec 2011
Residence time H vs D/W
Courtesy of J. Richmond-Bryant
Mid Manhattan05
• Significant fit:
o H = 22(D/W) -0.69
o R 2 = 0.62
o p < 0.001
Two Cities MM and
OkCity
• Poor fit:
o H = 51(D/W) -0.812
o R 2 = 0.035
o p = 0.022
JU2003: OklCity
• Scatter visible
• Novel methodology, under development
• Significant fit:
• Qualitatively similar results for two
o H = 296(D/W) cities
-0.812
o R 2 = 0.48
• Two cities differ quantitatively
o p < 0.0001
• Parameterizations can utilize fine scale
modeling to provide inputs for exposure
assessment
• Improved methodologies with multiple
canopy formulation sets such as from
ASI 2: URBAN CLIMATE AND AIR POLLUTION NUDAPT to be tested.
School of Architecture, The Chinese University of Hong Kong, Hong Kong, 7-8 Dec 2011
16