Environmental Engineering Reference
In-Depth Information
Oklahoma City. Wind directions averaged about 210° during IOP 02 and ~157°
during IOP 08. The vertical resolution of the SODAR was 10 m from 30 to 500 m
above ground level. Due to problems with the lower level data, only the SODAR
observations at and above 100 m were used. Below 100 m, wind speeds were
estimated using a neutral logarithmic profile: u(z) = u(100 m) ln(z/z
o
)/ln(100
m/z
o
), where z
o
is the roughness length (assumed to be 0.5 m), z is the height, and
u
100 m
is the SODAR wind velocity at z = 100 m. A displacement length of zero is
assumed in this suburban area and wind directions at z < 100 m are set equal to the
value at 100 m. For each IOP, five 15-min average profiles were constructed
beginning 15 min prior to the tracer release to 1 h after the beginning of the tracer
release (e.g., 1545-1700 UTC for IOP 02.)
3. Comparison of Model Results
The simulated wind speeds and directions, turbulent kinetic energy (TKE), and
concentrations are assessed by a combination of qualitative and quantitative com-
parisons. For example, qualitative analyses of contour plots (not shown here) may
show that the model can correctly simulate the channeling of wind down a side
street. Quantitative comparisons look at whether the model can match the observed
mean wind speed or concentration and the degree of scatter. Examples of scatter
plots of the near-surface wind outputs and concentration outputs for IOP 2 for the
periods, but the current manuscript has page limits. The figures illustrate the general
finding that there is little mean bias but much scatter, and that there is not much
Wind Speed
IOP2_CR1
16:00 - 16:30
4.0
3.5
3.0
2.5
2.0
1.5
LANL
ARL
IIBR
SAIC
1.0
0.5
0.0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
JU2003 Observed Wind Speed (m/s)
Fig. 1.
Wind speed scatter plot for IOP02 (day) for the four models
