Environmental Engineering Reference
In-Depth Information
(Fig. 1b)
shows that all models have skills in predicting LWC, while the LWC
from MesoNH (2.5 km) compares better with the observations.
1.2
4000
(a)
(b)
1-s meas. (Nevzorov)
2-min slicing (Nevzorov)
WRF-CHEM 27-km
MesoNH 2.5-km
GEM 2.5-km
aircraft altitude
3000
0.8
2000
0.4
1000
0
0
16:30
17:00
17:30
18:00
18:30
19:00
19:30
20:00
20:30
Time (UTC)
Fig. 1.
Modeled cloud compared with observation. (a). AURAMS LWC at ~1,400 m (msl)
overlaid with aircraft LWC measurement from FLT 16; (b). in-situ comparison between modeled
and observed LWC along the flight track
Modeled CO, NO
2
, O
3
, SO
2
, H
2
O
2
, and particle sulfate have been compared
sulfate.
(a)
(c)
WRF-CHEM 27-km
AURAMS 2.5-km SU2.5
WRF-CHEM 27-km, no aq chem
AURAMS 2.5-km SU2.5, no aq chem
AURAMS 2.5-km SU0.7
aircraft meas. (AMS)
WRF-CHEM 27-km
WRF-CHEM 27-km, no aq chem
AURAMS 2.5-km
AURAMS 2.5-km, no aq chem
MesoNH 2.5-km
aircraft meas.
8
16
in-cloud leg
1.2
in-cloud leg
6
12
0.8
4
8
0.4
2
4
0
0
0
40.4
40.8
41.2
41.6
42
42.4
42.8
40.4
40.8
41.2
41.6
42
42.4
42.8
Latitude (deg)
Latitude (deg)
8
16
(d)
(b)
LWC (Nevzorov)
6
12
below-cloud leg
below-cloud leg
4
8
2
4
0
0
40.4
40.8
41.2
41.6
42
42.4
42.8
40.4
40.8
41.2
41.6
42
42.4
42.8
Latitude (deg)
Latitude (deg)
Fig. 2.
Model-observation comparison of SO
2
(a, b) and particulate SO
4
(c, d) for FLT 16 (along
86.1 W): top panel - in-cloud leg, bottom panel - below-cloud leg
The 2.5-km AURAMS reproduces the observed plumes reasonably well but
with an apparent spatial shift. The emission data used in the MesoNH simulation
is inadequate, missing important sources in the area. New simulations with more
up-to-date NA emission inventory data are being pursued. The 27-km WRF-
CHEM is able to capture the broader structure of the plumes. Both AURAMS and
WRF-CHEM were run with aqueous-phase chemistry turned off as a sensitivity
test, and the modeled sulfate concentrations are significantly lower (
Fig. 2c, d).
