GAW requirements for improving standards for aerosol measurements. Paolo Laj, Chair GAW SAG-Aerosol

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1 GAW requirements for improving standards for aerosol measurements Paolo Laj, Chair GAW SAG-Aerosol

2 Fraction of CO2 emissions remaining in the atmosphere 1.0 Airborne Fraction % Trend: 0.27±0.2 % y -1 (p=0.9) 45% Le Quéré et al. 2009, Nature Geoscience; Canadell et al. 2007, PNAS; Raupach et al. 2008, Biogeosciences

3 How was this result derived from? Long term record (50 years) High precision measurements Adequate station density (ICOS network)

4 The same applies to Aerosol Primary and secondary particles High natural variability (shorter lifetime than GHG) Anthropogenic aerosol superimposed on natural background Not defined by a single parameter

5 Which are the Aerosol essential climate variables? Recommended Aerosol variable for Climate purposes (GAW SAG- Aerosol). GAW report 153

6 Challenges to respond to scientific objectives Scientific objectives Define trends and variability Quantify forcing and identify forcer emissions Underpinning Challenges Provide high quality, standardized, and traçable data sets to models Ensure proper diffusion of information Enlarge the network without lowering quality Secured data flows and costefficiency

7 How is GAW addressing these challenges? Defining Standard Operating Procedures GAW report 153 and updates (GAW-SAGs) Controlling implementation of SOPs and Quality World Calibration Centers (WCCAP) Ensuring Traçability of data and data quality World Data Centers (WDCA/EBAS)

8 Standard Operating Procedures Meant for users involved in academic research at first Address measurements from sampling to data distribution Facing the use of custom-made versus commercial instrumentation (and modified commercial instruments) Long-term observations versus exploratory campaigns (costefficiency, reliability, limited need for man-operations) Address data post-processing (raw, level 0, level 1, level 2), data flagging and (meta)data formatting Reporting to GAW (report # 153 for example) but not necessarily endorsed by all networks

9 Standard Operating Procedures Variable Recommended Instrument Unit / time Reference SOP integration Sampling Whole Air / PM10, PM2,5 Not applicable GAW report # 153 light scattering Multi-wavelenght nephelometer M -1 / 1 hour GAW report #200 coefficient light absorption Multi-wavelenght aethalometer or M -1 / 1 hour GAW report #200 coefficient single-wavelength Multi-angle Aerosol Absorption Photometer particle number concentration Particle counter CPC cm -3 / 1 hour Wiedensohler et al., Atmos. Meas. Tech., 5, , 2012, particle number Scanning Mobility Particle Counter size distribution (Coarse / small Optical particle counter (OPC) fractions) Chemical composition (EC/OC) Chemical composition (inorganic ions) -Off-line : filter based on PM10 and PM2,5 + thermo-optical instrument -Off-line : filter based on PM10 and PM2,5 + ion chromatography dn/dlogd /1h - On-line: aerosol mass spectrometry µg m -3 / 1h (non-refractory submicron aerosols, including major inorganic ions and organic matter) Wiedensohler et al., Atmos. Meas. Tech., 5, , 2012, In preparation µg m-3 / 12h to 48h Cavalli et al., Atmos. Meas. depending on sites, 1 Tech., 3, 79-89, 2010, time a week µg m -3 / 12h to 48h, 1 GAW report 153 and time a week EMEP/CCC-Report 1/95 (2001) In preparation (ACTRIS protocol)

10 Developing SOPs Activities funded under ragional programs (i.e. ACTRIS) or as voluntary action within GAW SOP is often defined by a limited network and then enlarged for wider application (EMEP in Europe) SOPs can evolve with evolving instrumentation CEN and ISO actions are part of the ulterior steps EC/OC CEN example

11 Extending EC/OC SOPs beyond GAW: CEN EUSAAR-2 methodology recently adopted by CEN for Elemental/Organic Carbon analysis 2 methodologies are adopted (IMPROVE/EUSAAR-2) An example of work with metrology institutes (others are engaged)

12 World Calibration Centres Development of Standard Operating Procedures. Performance audits at observation stations. Organization of intercomparison experiments Training and support of personnel in good practices for calibration, maintenance and operation. Provision of target gases, calibration of reference gases Continuous observation of the measurement quality Development of novel methodologies and instrumentation for variables World Calibration Center for Aerosol Physics (A. Wiedensohler) World Calibration Center for Reactive Gases Developping new Calibration Centers in Europe World Calibration Center for Online aerosol Chemistry Lidar calibration facility Cloud radar calibration facility Funded at National Level

13 World Data Centers Long-term sustainability, relevant data series Traceability: unique identification > attribution to the data provider Inter-operability: part of the WMO Global Atmosphere Watch system of data centres, with interfaces to the WMO Information System, searchable and accessible through WMO s information portals, and through the Global Earth Observation System of Systems (GEOSS). World Data Center for Aerosol World Data Center for Reactive Gases World Data Center for Greenhouse gases Funded at National Level

14 The Black Carbon Issue Carbonaceous particulate matter a high fraction of which is sp 2 -bonded carbon Consists of aggregates of spherules Individually, from <10 to (typically) 50 nm in diameter: respirable: plays a role in Air Quality Refractory Insoluble in water Strongly absorbs light across all visible wavelengths when freshly emitted, has a mass absorption efficiency of at least 5 m 2 g -1 at the mid-visible wavelength of 550 nm : plays a role in climate forcing

15 The Black Carbon Issue Light Absorption Coefficient (s ap ) Derived from optical methods, e.g., Filter-based (aethalometer, PSAP, MAAP, COSMOS) Suspended particles (e.g., photo-acoustic, extinction minus scattering) Equivalent Black Carbon (EBC) derived from s ap using a mass absorption efficiency (MAE) the MAE used to calculate EBC must be specified BC Properties: absorption Elemental Carbon (EC) Derived from measurement of CO 2 evolved from thermal or thermo-optical methods e.g., IMPROVE or EUSAAR protocols BC Properties: composition, refractory, (absorption) Refractory Black Carbon (rbc) Derived from laser incandescence methods BC Properties: composition, refractory, absorption

16 The Black Carbon Issue No current method combines all five essential characteristics of BC Consequently, no current method can justifiably claim to provide a quantitative measurement of BC Recommendations Use BC as a qualitative term referring to any of the quantitative methods the source/method of BC observations should be identified by using the respective terms EBC, EC, or rbc as defined above (corresponding to different manufacturers) But strong pressure from EPAs (and manufacturing companies) to develop a BC index for Air Quality purposes

17 The Black Carbon Issue No absolute satisfactory standard High variability of MAC leading to different BC values) Research community considers a reference method for BC is misleading Issue is being discussed

18 ENVIRONMENTAL RESEARCH INFRASTRUCTURES (EUROPEAN VIEW) Raw Level 1 Level 2 Data acquisition Quality control and higher-level products Designed as long-term entities to meet the requirements of continuous environmental observation; Comprise major scientific equipment as well as knowledge-containing resources such as collections, archives and thematic data Storage and visualization Support access and services within their data and RI facilities. USERS SERVICES WMO Services/training Have well developed e- infrastructure component (virtual access).

19 ENVRI plus :Environmental Research Infrastructures providing shared solutions for science and society H2020 INFRA (4 yrs) starting May 1st Coord. Werner Kutsch (ICOS) Co-Coord. Paolo Laj (ACTRIS) Work package title: Metrology, quality and harmonization addressing the need for standardization of key parameters common to different Ris traceability of measurement results to internationally agreed units of measurement standards with well-characterized uncertainties and well-monitored and maintained stabilities.

20 Conclusions Work needed towards more harmonization for the observation of Essential Climate Variables (Aerosol) Specific needs for long-term operations and for climate and Air quality research Difficulties to enforce use to a specific SOP How do we go from research communities to larger users of SOPs?