The WMO/GAW Integrated Global Aerosol Observing and Analysis System

1. John A. OgrenChairman, GAW Science Advisory Group for Aerosols Earth System Research Laboratory National Oceanic and Atmospheric Administration Boulder, CO, USA (with a lot of help from Len Barrie and Urs Baltensperger) The WMO/GAW Integrated Global Aerosol Observing and Analysis System

2. OBJECTIVE • Improve climate and air quality assessments and predictions...through measurements and analysis of the spatio-temporal distribution of aerosol properties for up to multidecadal time scales

3. Highlights from 2009 SAG Meeting • Updated the list of recommended variables • "core" variables unchanged • promoted some "intermittent" variables to "continuous" category, notably vertical profiles • Proposed transfer of WDCA to NILU • NILU is already hosting multiple long-term databases, can host WDCA with little extra work • Workshop on developing an international network of aerosol networks • Two new members, one new chairman • representing data user and satellite remote sensing communities

4. Components of Integrated System • In-situ observations • Surface sites, ships, aircraft, balloons • Remote sensing observations • Ground-based and satellite • Active (lidar) and passive (radiometer) • Models • Weather forecasting • Climate forcing predictions • Air quality • Synthesis Products

5. GAW Aerosol Variables • Core, continuous measurements • Aerosol optical depth at multiple wavelengths • Mass concentration in two size fractions • Major chemical components in two size fractions • Light absorption coefficient (at various wavelengths) • Light scattering coefficient (at various wavelengths) • Other recommended measurements • Vertical distributions • Microphysical properties(number concentration, size distribution, CCN) • Optical properties (backscattering) • Chemical properties (detailed composition vs. size) • Dependence on relative humidity • http://www.wmo.ch/pages/prog/arep/gaw/documents/gaw153.pdf

6. GAW Global Aerosol Network Status GAWSIS China Atmos. Watch Network • Many undersampled regions, many sampling sites not in database • SAG is working to recruit contributing networks and to update database Source: Zhang Xiao-Ye

7. Sites with 4+ years in operation,>50% coverage, as of March, 2004 Aerosol Optical Depth Networks Latitudinal distribution Polar regions: 4 Midlatitude North: 50 Tropics: 26 Midlatitude South: 10 Total (2004) 90 Major data gaps Africa, Asia, India, Polar region and Oceans 2004-2009 UPDATE: 40-50% increase of number of long-term sites (GAWPFR + AERONET), expansion to oceans with hand-held instruments tied to AERONET International: AERONET, BSRN, GAW-PFR, SKYNET National: Australia, China, Finland, Germany, Japan, Netherlands, Russia, USA(4) Courtesy of Chris Wehrli, Davos AOD Calibration centre

8. Cabauw Ispra Ensuring Comparable AOD Networks ADDITIONALLY: … algorithm comparisons … near-real-time data transfer Courtesy of Chris Wehrli, World Radiation Center Davos

9. GAW Aerosol LIDAR Observing Network “GALION” • A federation of seven regional networks • AD-NET violet, ALINE yellow, CISLiNet green, EARLINET red, MPLNET brown, NDACC white, REALM blue • ftp://ftp.wmo.int/Documents/PublicWeb/arep/gaw/gaw178-galion-27-Oct.pdf

10. GALION: Aerosol Vertical Profiles • Objectives: provide a climatology of the vertical component of aerosol distributions, and provide input to forecast models of "chemical weather" • At a minimum, perform measurements every Monday and Thursday, in a time slot of a few hours around sunset • Multiple networks… Systems range from automated backscatter lidars to multi-wavelength Raman lidars • Consequently… Products range from backscatter profiles to complex retrievals of aerosol microphysical properties

11. NOAA-federationNOAA-operated affiliated future sites GAW-affiliated Surface Aerosol Networks EUSAAR:20 European Supersites for Atmospheric Aerosol Research • The backbone of the GAW in-situ aerosol network • Not only stations, but audits, twinning, training, and scientific leadership

12. Forecast 18 UTC, 7 May 2002 30-hr forecast GAW/AERONET Aerosol Remote Sensing Stations CALIPSO Aerosol Lidar Integrated Products: Observations + Models NASA A-Train

13. Operational Research Dust Forecasting Centers

14. Challenges for Networks • Increased coordination within each type of network • measured parameters • sampling protocols, QA/QC, data processing • find partners in undersampled regions • Provide information on measurements to a common database • e.g., GAWSIS • need to keep information up-to-date • Provide data in a common format to users • increase percentage of stations submitting data • not necessary to have a common data center

15. Challenges for Integration • Enhanced interaction of the data generation and assimilation/modelling communities • Coordination among different types of measurements • Development of re-analysis products for combining different types of measurements • surface-based in-situ • surface-based remote sensing • satellite-based remote sensing • radiation budget

16. GAW SAG-Aerosol Members • John A. Ogren (Chairman), Urs Baltensperger, Leonard Barrie, John Gras, Raymond M. Hoff, Thomas Holzer-Popp, Stefan Kinne, Paolo Laj, Shao-Meng Li, Gelsomina Pappalardo, Christoph Wehrli, Alfred Wiedensohler, Julian Wilson, Xiao-Ye Zhang • SAG website: http://gaw.tropos.de/index.html • Comments and questions can be sent tosag-aero@tropos.de