Instrument : Aerosol Observing System (AOS)

Instrument Categories

Picture of the Aerosol Observing System

General Overview

The aerosol observing system (AOS) is the primary Atmospheric Radiation Measurement (ARM) platform for in situ aerosol measurements at the surface. The principal measurements are those of the aerosol absorption and scattering coefficients as a function of the particle size and radiation wavelength. Additional measurements include those of the particle number concentration, size distribution, hygroscopic growth, and inorganic chemical composition. The AOS measures aerosol optical properties to better understand how particles interact with solar radiation and influence the earth's radiation balance. The measurements are useful for calculating parameters used in radiative forcing calculations such as the aerosol single scattering albedo, asymmetry parameter, mass scattering efficiency, and hygroscopic growth. To learn more, see the preliminary data plots.

The first AOS is located at the Southern Great Plains (SGP) site in Oklahoma and has been operational since the beginning of April 1996. In 2005, a second AOS joined the first ARM Mobile Facility (AMF); the third AOS became operational with the second AMF. With funding from the American Recovery and Reinvestment Act of 2009, another AOS joined the ARM Facility and is available for deployments with either ARM Mobile Facility and/or the ARM fixed sites and capable of being deployed independently. For a list of instruments included in the AOS, see the Mobile AOS web page.

In March 2000, a long-term vertical profiling campaign began over the SGP site using a light aircraft. The measurements from the vertical profiles complement the surface measurements because the instrumentation on the airplane is similar to that at the SGP surface site. The aircraft measurements provide information on the aerosol vertical mixing.For more information and data, see the In-situ Aerosol Profiles (IAP) instrument page.

The AOS includes the following components:

  • acsm : Aerosol Chemical Speciation Monitor
  • aeth : Aethalometer
  • aosmet : Meteorological Measurements associated with the Aerosol Observing System
  • aps : Aerodynamic Particle Sizer
  • caps-pmex : Cavity Attenuated Phase Shift Extinction Monitor
  • ccn : Cloud Condensation Nuclei Particle Counter
  • clap : Continuous Light Absorption Photometer
  • cpc : Condensation Particle Counter
  • ghg : Greenhouse Gas Monitor
  • htdma : Humidified Tandem Differential Mobility Analyzer
  • nephelometer : Nephelometer
  • ozone : Ozone Monitor
  • pass : Photoacoustic Soot Spectrometer
  • pils : Particle Into Liquid Sampler
  • psap : Particle Soot Absorption Photometer
  • ptr-ms : Proton Transfer Reaction Mass Spectrometer
  • smps : Scanning mobility particle sizer
  • sp2 : Single Particle Soot Photometer
  • tracegas : Trace gas concentrations
  • uhsas : Ultra-High Sensitivity Aerosol Spectrometer

Output Datastreams

  • aos : Aerosol Observing System (AOS): aerosol data, 1-min
  • aoshumidograph : Settings and system measurements related to the PNNL-designed humidograph for the AOS
  • noaaaos : Aerosol Observing System (AOS): aerosol data, 1-min, mentor-QC applied
  • noaaaosavg : Aerosol Observing System (AOS): aerosol data, 60-min avg, mentor-QC applied
  • noaaaosfitrh : Aerosol Observing System (AOS): fitted relative humidity, mentor-QC applied

Primary Measurements

The following measurements are those considered scientifically relevant.


Eastern North Atlantic
ENAC1 Browse DataGraciosa Island, Azores, Portugal
North Slope Alaska
NSAX1 Browse Data Browse PlotsExternal Data (satellites and others)
Southern Great Plains
SGPC1 Browse DataCentral Facility, Lamont, OK
SGPS01 Browse DataSupplemental 1, Lamont, OK
ARM Mobile Facility
ACXM1 Browse DataOff the Coast of California - NOAA Ship Ronald H. Brown; AMF2
ASIM1 Browse DataAscension Island, South Atlantic Ocean; AMF1
AWRM1 Browse DataMcMurdo Station Ross Ice Shelf, Antarctica; AMF2
FKBM1 Browse DataBlack Forest, Germany retired
GRWM1 Browse DataGraciosa Island, Azores, Portugal; AMF1 retired
HFEM1 Browse Data Browse PlotsShouxian, Anhui, China retired
MAGM1 Browse DataLos Angeles, CA to Honolulu, HI - container ship Horizon Spirit; AMF2 retired
MAOM1 Browse DataManacapuru, Amazonas, Brazil; AMF1
NIMM1 Browse DataNiamey, Niger retired
OLIM1 Browse DataOlikiok Point, Alaska; AMF3
PGHM1 Browse Data Browse PlotsARIES Observatory, Nainital, Uttarkhand, India; AMF1 retired
PVCM1 Browse DataHighland Center, Cape Cod MA; AMF1
PYEM1 Browse DataPoint Reyes, CA retired
SBSS2 Browse DataSteamboat Springs CO, Christie Peak retired
TMPS1 Browse Data Browse PlotsU. of Helsinki Research Station (SMEAR II), Hyytiala, Finland; AOS
 retired = Originating instrument has been retired at this location

See Also


Derek Hageman
(303) 497-4652

Bill Behrens
Brookhaven National Laboratory
(631) 344-2906

Scott Smith
Brookhaven National Laboratory
(631) 344-7197

Janek Uin
Brookhaven National Laboratory

Cynthia Salwen
Brookhaven National Laboratory

Annette Koontz
Pacific Northwest National Laboratory
(509) 375-3609

Anne Jefferson
(303) 497-6493

Thomas Watson
Brookhaven National Laboratory
(631) 344-4517

Arthur Sedlacek
Brookhaven National Laboratory
(631) 344-2404

Chongai Kuang
Brookhaven National Laboratory
(631) 344-7257

Manvendra Dubey
Los Alamos National Laboratory
(505) 665-3128

Stephen Springston
Brookhaven National Laboratory
(631) 344-4477

Gunnar Senum
Brookhaven National Laboratory
(631) 344-3896