Aerosol Observation System (AOS) - IOP
Instrument Categories: Aerosols
General Overview
The aerosol observation 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 system is located at the Southern Great Plains (SGP) site in Oklahoma and has been operational since the beginning of April 1996. The Aerosol Group at NOAA/Climate Monitoring and Diagnbostics Laboratory (CMDL), now the Global Monitoring Division (GMD), took over the mentorship of the AOS in early 1997. 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, see the In-situ Aerosol Profiles (IAP) instrument page.
The IAP system underwent major upgrades in 2005 and 2006, including moving to a larger Cessna 206 airplane, installation of a more efficient inlet system that samples particles up to 8 um diameter, and addition of two more humidified nephelometers to allow better characterization of vertical profiles of aerosol hygroscopic growth. IAP data are available here.
IOPs Where the Instrument was Used
Aerosol IOP
Southern Great Plains, 2003-05-01 -- 2003-05-31
Primary Measurements Taken
The following measurements are those considered scientifically relevant. Refer to the datastream (netcdf) file headers for the list of all available measurements, including those recorded for diagnostic or quality assurance purposes.
- Aerosol absorption
- Hygroscopic growth
- Particle number concentration
- Particle size distribution
- Inorganic chemical composition
Mentor(s)
John Ogren
(303) 497-6210
John.A.Ogren@noaa.gov
Anne Jefferson
associate
(303) 497-6493
anne.jefferson@noaa.gov
Patrick Sheridan
associate
(303) 497-6672
patrick.sheridan@noaa.gov