Environmental Engineering Reference
In-Depth Information
3. Results
Observations from several surface stations were available for the summer campaign.
Some of them are located within the inner model domain, thus, we could compare
them with more than one grid of the model. “Igud station” (main municipal's
station) results are presented in
Fig. 2,
showing a relatively good agreement for
wind speed. However, the model predicted lower temperatures and longer periods
of south-east winds at night (probably land breeze) than observed. The reason for
this disagreement has still to be elaborated. Both discrepancies seem to be related
since southeasterlies at night are associated with cooler air (by about 5-6°C).
360
35
12
30
300
10
25
240
8
20
6
180
15
4
120
10
2
60
5
0
0
0
6 2 8 4 0 6 2 8 4
6 1218243036424854
6 2 8 4 0 6 2 8 4
(b)
(c)
(a)
Fig. 2.
“Igud” station located in Haifa Bay, was one of the launching sites. Model results
compared with observations are shown on a 48 h time scale (GMT); wind speed (m/s) (a), wind
direction (deg) (b), Temperature (°C) (c); model results in black
•
observations in
gray
g
Radiosonde profiles showed no ground inversion in the morning, while the
model predicted one, as well as cooler temperatures at ground level. The profile
demonstrated in
Fig. 3 s
hows a case where the model managed to predict the marine
inversion based at about 1,000 m height, though not as strong as the measured
one. A higher inversion measured at about 2,400 m was not predicted by the
model. This one was probably a subsidence inversion, which did not appear in the
NCEP reanalysis used for initializing the model, and the coarse vertical resolution
of the model at this height could be another reason for the disagreement. The wind
direction profile in
Fig. 3
shows a good agreement between the radiosonde and the
model up to 2,000 m, while above that height the model and observations depart
from each other even higher than 30° which is beyond the noise uncertainty (±30°).
4. Summary
Upper air and surface data were collected during a special observation campaign
at the Haifa Bay region at the north of Israel. This area is characterized by a com-
plex topography, vicinity to the Mediterranean Sea, heavy industry and periods of
high air pollution. The data was used to validate high resolution simulations
conducted with the RAMS model. In general, results showed good agreements,
suggesting the model calculates realistic fields. However, comparisons in the
