Aerosol Robotic Network

Aerosol Robotic Network
Name	Aerosol Robotic Network
Abbreviation	AERONET
Formation	1993
Type	Research network
Headquarters	NASA Goddard Space Flight Center
Region served	Global
Leader title	Principal Investigator
Parent organization	NASA

Aerosol Robotic Network

A global ground-based photometer network provides long-term aerosol optical depth and sky radiance observations supporting NASA, European Space Agency, NOAA, JAXA, ISRO, CSA (Canada), UK Space Agency and other agencies. The network interfaces with satellite missions such as MODIS, VIIRS, CALIPSO, MISR, Sentinel-3, Copernicus Programme and research programs like ACE (Aerosol Characterization Experiment), AEROCOM and GLOBE Program, enabling validation for climate studies, air quality assessments, and radiative forcing estimates used by the Intergovernmental Panel on Climate Change, World Meteorological Organization and United Nations Environment Programme.

Overview

The network consists of calibrated Cimel sunphotometers and other sun/sky photometers operated at surface stations distributed across continental Africa, Antarctica, Asia, Europe, North America, Oceania and South America. Observing strategies are coordinated with field campaigns such as ACE-Asia, Sahara Dust Experiment (SHADE), AMMA (African Monsoon Multidisciplinary Analysis), HIPPO, and satellite overpass schedules including Terra (satellite), Aqua (satellite), Suomi NPP, and Sentinel-2. Data feed into modeling efforts like GEOS-Chem, ECMWF, WRF-Chem, GISS ModelE, HadGEM, and IPSL-CM. The network supports applied programs including NASA Earth Science Division, European Commission, EPA (United States Environmental Protection Agency), and regional air quality agencies.

History and Development

Initial concept and prototype deployments emerged from collaborations among researchers at NASA Goddard Space Flight Center, University of Lille, Laboratoire d’Optique Atmosphérique, CNRS, CSIRO, Scripps Institution of Oceanography, University of Maryland, and Rutherford Appleton Laboratory. Early validation efforts aligned with ASTER, TOMS, and early MODIS calibration/validation. Expansion accelerated through partnerships with the World Radiation Center, AEROCOM, GAW (Global Atmosphere Watch), CEOS and national programs in Japan, India, China, Brazil, South Africa and Australia. Milestones include standardized calibration protocols developed with NIST, intercomparison workshops hosted at ESA ESRIN, and integration into major campaigns such as SAFARI 2000 and ARCTAS.

Instrumentation and Operation

Primary instrumentation comprises Cimel CE-318 sun/sky photometers with spectral channels tied to radiometric standards maintained by NIST, PTB and regional labs such as AERONET–PHOTONS. Deployment sites include observatories like Mauna Loa Observatory, NOAA Mauna Loa Global Monitoring Laboratory, Barrow Observatory, Izaña Atmospheric Research Center, Puy de Dôme Observatory, Kopernik Observatory and research stations at Palmer Station (Antarctica), Station Nord, and Ny-Ålesund. Operators receive training through workshops at NASA Goddard, University of Colorado Boulder, National Center for Atmospheric Research and regional universities. Routine operations follow automated sun-sky sequences, calibration checks, and sky scanning protocols coordinated with overpass times of Aqua (satellite), Terra (satellite), Suomi NPP, and research aircraft such as ER-2 and DC-8.

Data Products and Quality Control

Standard data products include aerosol optical depth, Ångström exponent, column water vapor, sky radiances, and inversion products for size distribution and refractive index. Level 1.0, 1.5 and 2.0 processing tiers are archived and disseminated via portals used by NASA Earthdata, GEOSS, Copernicus Climate Change Service, and data centers like NCEI and PANGAEA. Quality control follows cloud-screening, instrument calibration, and intercomparison procedures developed with AEROCOM and validated against references such as AERONET_NetRadiometer intercomparisons and campaigns like DRAGON. Metadata standards align with ISO 19115 and community conventions employed by ESGF, CF (Climate and Forecast) metadata convention and OGC.

Scientific Applications

Data support retrieval validation for satellite sensors including MODIS, VIIRS, Sentinel-3 OLCI, CALIOP, MISR, and assimilation into reanalyses like MERRA-2, ERA5 and JRA-55. Studies using the network inform estimates of aerosol radiative forcing in IPCC assessments, air quality forecasting in WRF-Chem and CAMS, and health impact assessments referenced by WHO. Applications include desert dust transport studies linked to events such as Saharan Air Layer outbreaks, biomass burning aerosol characterization tied to Amazon rainforest fires, urban pollution episodes in Beijing, Delhi, and Los Angeles, and polar aerosol processes relevant to Arctic amplification and Antarctic ozone depletion research. Interdisciplinary projects connect with Paleoclimate proxies, ocean biogeochemistry through dust deposition studies, and engineering efforts in instrument development by Spectral Devices and manufacturers.

Governance and Collaborations

Governance involves coordination among principal investigators, host institutions, and data centers including NASA Goddard Space Flight Center, Laboratoire d’Optique Atmosphérique, University of Colorado Boulder, NASA Jet Propulsion Laboratory, and international partners under frameworks such as GCOS, WMO and CEOS. Collaborative networks and projects include AEROCOM, GEO, GEOSS, ACTRIS, GAW, ICARE, SCALE and regional consortia in Africa, Asia-Pacific, Latin America, and Europe. Funding and support derive from agencies such as NASA, NSF, European Commission, CNES, JAXA, ISRO, UK Research and Innovation, and national research councils.

Category:Atmospheric sciences