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(−62.2% < MNBE < −54.8%, 57.6% < MNGE < 63.4%). However, the model
presents a good correlation (0.53 < cor < 0.72) with the observations, the lowest
correlations corresponding to spring where the DREAM model did not capture
several dust outbreaks. Levels of PM
2.5
present similar tendency than PM
10
,
(−56% < MNBE < −35.4%, 55.1% < MNGE < 62.6%), although slightly lower
correlations are obtained (0.44 < cor < 0.58). This problem is related to the
uncertainty in our knowledge of the sources, and dynamical or chemical processes
of secondary aerosol.
Fig. 2.
Time series at EMEP stations over spring and summer (2004): SO
2,
NO
2
, and O
3
on
hourly basis and PM
10
on daily basis
Table 1.
Monthly statistics obtained with the CALIOPE system for gases at the EMEP stations
(hourly data) and particulate matter (daily data): number of data (NDATA), cor, MNBE (%),
MNGE (%), RMSE (µg m
−3
).
O
3
NO
2
SO
2
Pe riod
NDATA
cor
MNBE
MNGE
RMSE NDATA
cor
MNBE
MNGE
RMSE NDATA
cor
MNBE MNGE RMSE
Mar
23066
0. 48
-15.2
23.5
27.4
8180
0.63
-53.7
63.7
26.9
1229
0.56
-24.4
69.1
9.6
Apr
26964
0. 45
-10.1
17.5
21.9
6574
0.55
-52.8
65.4
21.8
689
0.47
36.0
113.3
18.1
May
26087
0. 55
1.5
16.6
19.9
6386
0.53
-49.7
64.0
19.1
664
0.44
15.6
94.2
11.0
Jun
20387
0. 58
-1.0
14.9
19.3
6400
0.41
-51.5
63.8
13.4
662
0.50
136.8
202.6
28.9
Jul
18931
0. 61
-5.1
14.7
20.9
6040
0.42
-54.2
66.0
14.9
841
0.46
45.6
127.0
19.2
Au g
19697
0. 60
-4.5
13.1
18.6
6031
0.50
-55.6
64.4
14.4
753
0.55
28.2
116.2
13.9
PM
10
PM
2.5
Pe riod
NDATA
cor
MNBE
MNGE
RMSE NDATA
cor
MNBE
MNGE
RMSE
Mar
533
0. 53
-60.4
63.2
22.9
257
0.44
-56.0
62.6
1 8.4
Apr
489
0. 53
-57.9
60.1
14.9
167
0.57
-55.3
58.8
1 2.3
May
456
0. 53
-54.8
57.6
12.5
187
0.53
-51.0
55.1
9.4
Jun
558
0. 62
-55.1
58.2
13.0
255
0.49
-35.4
55.7
9.4
Jul
622
0. 65
-62.2
63.4
24.3
315
0.58
-50.2
57.7
1 2.1
Aug
546
0. 72
-60.0
61.7
14.6
248
0.46
-38.2
61.3
1 2.3
