Proceedings - C-SRNWP Project

• resolution of meteorological fields: 9.5 km spatial, every 1 hour,
• time period: days with measured maximum hourly ozone concentration above
165µg/m 3 at least at one measuring site in Slovenia in months from April to September
2004 and 2005,
• hours of arrival: 10, 12, 14, 16, 18, 20 UTC,
• arrival level: 50 and 200 m above ground, 1000, 1500, 3000 and 5500 m above mean
sea level.
Average number NG - 50
Average age NG - 50
50 o N
48 o N
46 o N
44 o N
42 o N
180
160
140
120
100
80
60
50 o N
48 o N
46 o N
44 o N
42 o N
90
80
70
60
50
40
30
40 o N
40
40 o N
20
38 o N
20
38 o N
10
4 o E 8 o E 12 o E 16 o E 20 o E
4 o E 8 o E 12 o E 16 o E 20 o E
Figure 5: The average number density (left) and the average age of a trajectory in grid box (hours) of polluted
trajectories arriving at Nova Gorica 50 m above the ground.
Results of analysis made for polluted backward trajectories arriving at Nova Gorica 50 m
above ground are presented on Figure 5. Areas of high trajectory average number density
indicate possible source regions of ozone precursors. Other analysis, among them average
trajectory age, confirm that in Nova Gorica case with ozone and it’s precursors polluted air
masses most probably originate from the Gulf of Trieste and the west Coast of Istria.
Similarly, main source regions of photochemical pollution were determined also for some
other measuring sites in Slovenia.
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