1. H. Fagerli, TFMM Bordeux, 24-26 april 2008
Using the EMEP Intensive campaign data for evaluating the EMEP model – first results for N
H. Fagerli, TFMM Bordeux, april 2008

2. Background
Essential for the deposition/transport how much is in gas phase and how much is particles
Little data (and with artefacts) from the EMEP network
’Only’ daily data – difficult to study processes that differ in day/night

3. Questions Do we distribute gas-particle correctly ?
Coarse versus fine nitrate
Do the model have the correct diurnal variations?
(results with the updated model version)
1.) Some material from before

4. Available data (total=13 sites)
HNO3
NH3
PM1
PM25
PMco
PM10
aerosol
GB33
06,30mn
GB36 06
GB48
06,07
CH02
06,07,
07,
DE44 07
IT04
NL11
06(no3),07
IE31
AT02
ES17
FI17
IT01
NO01
Blue: hourly data
Red: daily data
Lots of problems in measurement data!

5. June, 2006
Daily
Hourly
Fine nitrate tends to be underestimated in june 06
No systematic relation between over-/underestimated
HNO3 and part. NO3

6. June, 2006
(Fine and) Coarse nitrate
slightly underestimated

7. EMEP network – june 2005 HNO3: mixed Nitrate: underestimated
=same conclusions as from
Intensive campaign

8. January, 2007 Nitric acid underestimated in winter
Nitrate ok except IT04

9. January, 2007
Fine nitrate slightly underestimated, coarse nitrate mixed, PM10 low

10. EMEP network – jan 2005 HNO3: mixed (IT01 overestimated)
Nitrate: mixed (in general not as good comparison as the
campaign)

11. Summary, HNO3-NO-3 partitioning
Both coarse and fine nitrate underestimated in summer, HNO3 mixed. Agrees with comparison to EMEP network
In january EMEP Intensive campaign, the modelled nitrate is in agreement or slightly lower than measurement for nitrate (fine and coarse). HNO3 is underestimated. Comparison with EMEP network show mixed results for both.
Do different methods explain this or the selection of sites?

12. June, 2006
No systematic behaviour for NH3/NH4+

13. EMEP network – june 2005 NH3, NH4+ and sum mixed, but somewhat
Low (too little formation
of NH4NO3?)

14. January 2007
No systematic behaviour for NH3/NH4+ fine

15. EMEP network, jan 2005
NH3 and NH4+ ; no systematic behaviour

16. Conclusion NH3-NH4+ partitioning
Mixed NH3 in june, somewhat low NH4+ -campaign: agree with EMEP network comparison
Intensive campaign and network show no systematic behaviour in january

17. Diurnal variation, Cabauw
No systematic
Behaviour in summer
Typically
low in winter
Model capture peak around noon (except GB48 do not have this- very little and strange data)
and the lack of daily variation in winter

18. Ammonia, daily variation, june 06
Model and observations show opposite variation (except for NL11). Most extreme example:

19. Ammonia, daily variation, january 07

20. If NH3 is too low during the day – could this be the reason for underestimating NH4NO3 in june (only 3 sites to look at)?
NH3
HNO3
Site: HARWELL (GB36)
NO3- (PM25)

21. Diurnal variation of NH3 emissions changed
HNO3
Site:HARWELL (GB36)
NO3- (PM25)

22. Conclusions
The new data allows for a more comprehensive evaluation of the nitrogen chemistry in the model – we have just begun…
In general better comparison with Intensive campaign data
Using campaign data or data from the ’standard’ EMEP network give same conclusions (except for HNO3 winter):
No systematic behavior for reduced nitrogen. Low nitrate in summer, low HNO3 in winter. Low coarse nitrate.
Consequences for the EMEP model:
Revise NH3 emissions diurnal variation?
Look at temperature effect in the equilibrium module
Formation of coarse nitrate

23. Different methods, IT01, 2006
Filterpack+ denuder
PM10
PM25

24. Different methods, IT01, 2007
Filterpack
+ denuder
PM25

26. GB48

27. Cabauw, june 2006
Why so much PMco?

28. Cabauw, january 2007

29. Cabauw (NL11) JUNE 06 JAN 07 High HNO3/low NO3(coarse)
Substantial coarse no3
Low nh3
All comp underestimated
Low/no coarse NH4

31. Diurnal variation of NH3 emissions changed
HNO3
Site: Auchencort (GB48)
NO3- (PM25)

32. Diurnal variation of NH3 emissions changed
HNO3
Site: Cabauw (NL11)
NO3- (PM25)