Massimo Vieno, Eiko Nemitz CEH Edinburgh & Univ. Edinburgh Real-Time Measurements during the EMEP Intensive Measurement Period and Application of EMEP4UK Massimo Vieno, Eiko Nemitz CEH Edinburgh & Univ. Edinburgh In this presentation we present preliminary results of the real-time measurements conducted during the EMEP Intensive Measurement campaigns 2006 & 2007. With real-time measurements we refer to measurements of aerosol composition and inorganic pre-cursor gases made with a time resolution of one hour or better. We also present first applications of the EMEP4UK model to reproduce these measurements and the current plans for the 2008 & 09 campaigns.

Intensive Measurement Campaigns (June ’06 & Jan ‘07) Daily aerosol composition  Wenche Aerosol physics (size spectra)  Jean-Phillippe ? Real-time measurements of aerosol composition & inorganic gases (hourly or better)  This presentation During the intensive measurement periods 2006/07, daily measurements were made of aerosol composition, which were analysed off-line. These will be presented (or have been presented) by Wenche. In addition, aerosol size spectra were measured at selected sites. Jean-Phillippe Putaud is leading the meta analysis of this dataset. We here concentrate on the analysis of the real-time measurements made at 7 sites across the EMEP network.

Why make real-time measurements? Daily measurements capture mesoscale transport phenomena But: hourly measurements are needed to capture diurnal variations due to: Changes in emissions Changes in boundary layer height Changes in (T & RH-dependent) gas / aerosol equilibria I think this slide is pretty self-explanatory.

Aerosol Mass Spectrometer vs. wet chemistry instruments AMS MARGA/ GRAEGOR Gases No Yes (NH3, HNO3, HCl, SO2,HNO2) Transmission 40 – 600 nm (~PM1) PM2.5 & PM10/TSP Sizing Yes Aerosol fraction Non-refractory only: NH4+, NO3-, SO42-, Cl-, OM, H2O Total: NH4+, NO3-, SO42-, Cl- (MARGA only: Na+, K+, Ca2+, Mg2+) Two types of real-time instrumentation were used. These measure two different entities. The Aerosol Mass Spectrometer measures sub-micron non-refractory aerosol components (need to volatilise at 600 deg C), while the wet chemical analyses measure total water soluble components. The AMS also measures organic mass, while the wet chemistry systems also measure inorganic reactive gases such as NH3, HNO3, HCl and SO2.

Example Time Series UK 40 (continuous sampling at Auchencorth Moss UK Supersite) This is an example of the inorganic gases and aerosol components measured with an online technique at the UK supersite Auchencorth in Southern Scotland. These measurements are now continuously running at this site.

Network of 2006/07 Real-time Measurements Auchencorth (GB40) Cabauw (NL11) Ispra (IT04) Harwell (GB36) Mace Head (IE31) This figure shows the different sites at which real-time measurements were conducted in 2006/07. It is clear that the dataset so far is biased towards NW and central Europe.

Meteorology during 2006/07: Example Back-trajectories Jan 07 was an unusually mild winter month Sites better connected in Jan-07 than in Jun-06 19 June 2006 17 Jan 2007 Backtrajectory analyses are being performed to analyse the transport between sites. Here two examples of 5-day trajectories are shown. In general, sites were better connected during the winter period than during the summer period. The German Melpitz site, in particular, reported that Jan 2007 was unusually warm with a smaller occurrence of easterly winds than usual (and thus less import from E. Europe / Russia).

Measured time-series: June 2006 This is a stacked plot of the aerosol composition measured during the June campaign. What is clear from this graph, is that in N Europe concentrations are more episodic, caused by long-range transport events, while in central Europe, concentrations tend to be more consistent and follow local controls. One can also discern certain diurnal patterns which will be even more apparent in the next few slides (point to diurnal patter in CH02 nitrate and organics, for example).

Averaged Diurnal Cycles: Summer Nitrate Cabauw (NL) Payerne (CH) Auchencorth (UK) Ispra (IT) One of the key results from the hourly measurements is the investigation of diurnal variations. This slide shows averaged diurnal cycles of aerosol nitrate during the June 2006 campaign. Cabauw, Payerne and Ispra all show clear diurnal cycles, which peak at different times in the day. By contrast, nitrate at the Scottish site is governed by long-range transport processes, rather than local emissions and temperature effects. These different processes will be a challenge for the models to reproduce correctly.

Averaged Diurnal Cycles: Summer Ammonia Auchencorth (UK) Harwell (UK) Ispra (IT) Cabauw (NL) Ammonia also shows different diurnal cycles at different sites. At the English and Italian sites, NH3 peaks during the day, while it peaks at night at the Dutch site and is relatively flat at the Scottish more remote site. Daytime peaks may be due to the temperature dependent equilibrium of NH4NO3, while night-time maxima could be due to more shallow boundary layer height.

Averaged Diurnal Cycles: Summer nitric acid & hydrochloric acid During the summer, both HNO3 and HCl show a maximum in the early afternoon at all sites. Conventionally it is thought that most of the HCl originates from seasalt reaction with HNO3 and thus a correlation between HNO3 and HCl is to be expected. However, it is curious that (at least in summer) the HCl concentration exceeds that of HNO3 in equivalent terms and that the initial analysis suggests that HCl is present even when there is no Na present. This suggests that there may be another source of HCl following a similar trend or the HCl formation may occur on surfaces. The AMS data indicate that there is very little volatile aerosol Cl at all sites, so it is unlikely that this temporal pattern is controlled by the thermodynamic equilibrium of NH4Cl. There are very few measurements of this kind in the literature.

Coarse vs. Fine Mode NO3- Harwell (June 2006): 49% fine : 51 % coarse Harwell (Jan 2007): 61% fine : 39 % coarse In addition to getting the diurnal pattern of the concentrations, the instrumentation applied here also distinguishes between gas and aerosol phase without artefacts. This enables NH4NO3 concentrations to be measured without evaporation losses. This figure shows the June time series of nitrate at UK 33, broken into PM2.5 and coarse (PM10-PM2.5) components. This provides a stringent test for the models to get the fine / coarse aerosol partitioning right.

Data usage Study transport across Europe Contrast local controls (e.g. NO3-): transport vs. emissions vs. thermodynamics Integrate with daily measurements (at more sites) Provide dataset for validation of atmospheric transport models at European and national scale

Timing of Next Campaigns EMEP Campaign 2008: 15 Sep - 17 Oct 2008 EMEP Campaign 2009: 23 Feb – 27 Mar 2009 please take notes if people approach you. There is biaflux funds for trans-national access people can apply for (see slides).

Objectives & Challenges for 2008/09 Campaigns Improved coverage in Easter and Southern Europe Link to aerosol physics from EUCAARI (size distributions, air ions, hygroscopicity) Aerosol climatology based on Aerosol Mass Spectrometry (Synchronized) database for OM analysis (e.g. POA vs. SOA) Improved gas phase measurements (HNO3 & HNO3) Improved EC/OC (EUCAARI methodology) Improved mass closure (incl. water, OC/OM, mineral dust) 14C & Levoglucosane

AMS Size Distribution at CEH EMEP (UK 36) The more extensive AMS network will provide sub-micron aerosol size distributions in addition to mass loadings. This graph shows a 4 ½ day example time series from Scotland, where time is plotted along the x-axis, the diameter is on the y-axis and the colour indicates how much mass loading is found in what size.

AMS Aerosol Climatology (not synchronised) Recently, AMS datasets have been summarised to provide a global aerosol climatology. However, these measurements cover both background locations and cities and were taken at different times. We are hoping to provide a harmonised approach to derive improved pictures for Europe.

The mass spectrum of the organic aerosol component measured with the AMS provides information on the type of organic aerosol. At least two classes can be distinguished: hydrocarbon-like organic aerosol (primary combustion particles) and oxygenated organic aerosol (photochemically processed, secondary aerosol). Sometimes, OOA can be further deconvolved into more and less oxygenated aerosol classes. This analysis will be performed for both the old and new campaigns to provide a test database of HOA and OOA for model assessment.

Map of Likely Sites of AMS Measurements during 2008/09 EMEP Campaigns The sites for the extended measurement network for the intensive campaigns 2008/09 are collocated with sites used by the EU programmes EUCAARI and EUSAAR, together with some other national EMEP supersites. These are roughly oriented along to intersecting transects. Much better coverage will be achieved than during the earlier measurements of 2006/07.

This table shows the sites currently envisaged to be operated during the EMEP Intensive Periods 2008/09. It would be good if more sites could find a method to measure NH3 and HNO3.

Funding Funding sources: Organisation: National governments EUSAAR (provision of site infrastructure): www.eusaar.net European ACCENT/BIAFLUX IP (trans-national travel funds for 2008 campaign): www.accent-network.org; applications to kjf@ceh.ac.uk ESF INTROP Combine with other project commitments Organisation: Eiko Nemitz (en@ceh.ac.uk) Andre Prevot (EUCAARI) (andre.prevot@psi.ch) Wenche Aas (EMEP, NILU, Norway) (waa@nilu.no ) One challenge is to provide better coverage in Southern and Eastern Europe. As there are fewer instruments available in these countries, an effort should be made to deploy surplus instruments from N. and Central Europe in these countries. Travel grants are available from ACCENT/BIAFLUX and Introp. For example, the Univ. of Manchester is planning to deploy one of there AMS instruments at K-Puszta (Hungary), CEH Edinburgh will deploy an AMS instrument near Barcelona and PSI Switzerland will deploy and AMS in Greece.

Groups involved in 2006/07 CEH Edinburgh, UK IFT Leipzig, Germany Gavin Phillips, Rick Thomas, Chiara Di Marco, Eiko Nemitz IFT Leipzig, Germany Laurent Poulain PSI Switzerland Rami Alfarra, Andre Prevot University of Kopio, FI Jukka Rukkainen, Ari Laaksonen ECN Petten, Netherlands Rene Otjes JRC Ispra, Italy Jean-Phillippe Putaud

Model comparison EMEP4UK 2.44 – WRF 2.2 nested within EMEP 2.44 Europe –WRF 2.2

EMEP4UK Auchencorth Auchencorth SO4 June 2006 (hourly) 5 10 15 20 25 5 10 15 20 25 01/06/2006 06/06/2006 11/06/2006 16/06/2006 21/06/2006 26/06/2006 time / hours concentration / ug m-3 EMEP4UK (Auch) MARGA (Auch) AMS (Bush)

EMEP4UK Harwell

EMEP4UK Mace Head