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Methods and procedures for data quality control in the GAW/WMO Aerosol measurement program

Paolo Laj CNRS‐U. Grenoble‐Alpes / U. HelsinkiWMO‐GAW SAG Aerosol Chair

Global Atmosphere WatchResearch Enabling Services

22

Anthropogenic Forcing on Climate IPCC 2013

“the largest uncertainty to estimates and interpretations of the Earth’s changing energy budget”

–0.9 [–1.9 to −0.1] W m−2

(medium to low confidence) High regional variability 

2.83 [2.26 to 3.40] W m–2

(high to very high confidence)Low regional variability

32

3

Deadly Particles ….in the World

42

Aerosol Components acting on RF and Health

Emission Sources 

Intrinsic Optical Properties

4‐D Variability

Natural 

Anthropogenic

SecondaryPrimary

Scattering

Absorbing

CoarseFine

Short‐lived

Relatively Long‐lived

UpperatmosphereNear‐surface

List of variables with established GAW‐SOPs

AQ                                                                                    C

GAW network for aerosol variables

• Data access through WDCA

• A large and increasingcommunity of users

• Need to ensure very highquality of data and highdegree of standardization

• A agreed protocols and traceability procedures

• A need for skilled

Standard Operating Procedures

• Recommended procedures for Aerosol measurements

• Inlet‐to‐data‐provision approach

• WIS compatible

• GAW – IP general procedures

User Requirements(RRR)

ScientificExpert 

CommitteeWCC

SOP Recommendation

Approval by SAG‐Aerosol

Network Implementation in 

(WCC)

Peer‐review

CEN / ISO 

World Calibration Centers Aerosol

Capacity building

Calibration and intercomparison workshops

Reference instruments 

Audits and site visits

Twinning Partnership

Advice in setting up aerosol programs (SOP)

World Calibration Center for  Aerosol

Physics

World Optical DepthResearch and 

Calibration Center 

QA/QC loop in GAW Aerosol 

On site audits

Instrument performance lab‐ check 

Quality Assessment OK 

No

WCC

Yes

WCC go/nogo

WDCANRT Specific use

(Copernicus)

Observation platform

TrainingTechnical/Data Mgt

GAW‐TEC

USERS

Increasing provision of GAW Aerosol data 

2006 201610 41

Number of stations providing aerosolparameters record >10 years

2006 201638 146

Number of stations providing aerosolparameters to WDCA

2006 201616 >150

Number of Instruments checked by WCCAP

Essential contribution from EU commission 

funding to:  

NRT Data provision 

2010 20166 39

Number of stations providing aerosolparameters in NRT to WDCA

Essential contribution from EU commission 

funding to:  

Increasing use of GAW Aerosol data 

2010 2016500 >2000

Number of IP access to WDCA/month

Where Are the WDCA Users Located? Number of Unique Users (IPs) by Country (2015)

Associated publications Essential contribution from EU commission 

funding to:  

QA/QC in Contributing Networks to GAW

• Contributing networks are part of GAW strategy

• Should apply an established quality control protocoland provide a statement on the quality of itsdatasets. 

• Evaluation of measurement quality is performed in association with the relevant World Calibration Center (WCC)

• High GAW Quality standards may not apply

• Compliance with GAW data policy

Work with Metrology Institutes towards iso‐standards

• Established collaboration with BIPM and associatedNMIs CEN/TC 264/WG 32 Air quality ‐ Determination of 

the particle number concentration CEN/TC 264/WG 35 EC/OC in PM

• Reference Standard for Black‐Carbon Work towards BC definition (Petzold et al., 2013)  METAS, NPL, TROPOS, FMI, PSI for the definition of a 

BC standard CEN/TC 264/ WG35 follow‐up: evaluation of 

equivalence between filter‐based and on‐line light‐absorption measurements

Future Issues regarding QA in GAW

Maintain Observing Platforms in operation (incl. skills of station operators)

Towards new Aerosol Calibration Centers  Lidar CC, On‐line Aerosol Chemistry CCMissing Aerosol chemistry CC

Need for Regional Calibration Centers  Promote establishment of Regional Networks outside Europe and N. America

Discussion with NPL India Regional training activities  

Promote work with National Metrology Institutes 

QA/QC policy with Contributing networks and Citizen observatories