VAP : Aerosol Optical Depth, derived from atmospheric extinction of solar irradiance (AOD)

Instrument Categories
Aerosols, Derived Quantities and Models

The core purpose of the ARM Facility is to reduce uncertainties in climate model predictions. A dominant source of uncertainty in these models is the radiative impact of aerosols, which has spawned a major effort in ARM to measure aerosol properties.

The Aerosol Optical Depth (AOD) value-added product (VAP) is concerned with several important aerosol radiative properties. The most important of these is the aerosol optical depth (AOD), which is a measure of the total aerosol burden in the atmosphere. The spectral dependence of AOD, typically described by the Angstrom exponent, is also an indicator of particle size, with large particles having Angstrom exponent values near zero and smaller particles exhibiting larger Angstrom exponent values. Improved knowledge of these basic aerosol properties will help reduce the uncertainties associated with aerosol effects in climate models.

The AODs have been derived from the MFRSR, NIMFR and SASHE instruments. For more information about these products, please refer to the MFRSR/NIMFR technical report and SASHE technical report or to the output product pages linked below.

Output Products

  • mfrsraod1mich : MFRSR: derived total & aerosol optical depth from 1st Michalsky algorithm
  • nimfraod1mich : NIMFR: derived total & aerosol optical depth from 1st Michalsky algorithm
  • sasheniraod : Shortwave Array Spectroradiometer-Hemispheric, NIR Aerosol Optical Depths
  • sashevisaod : Shortwave Array Spectroradiometer-Hemispheric, VIS Aerosol Optical Depths

Primary Measurements

The following measurements are those considered scientifically relevant.


North Slope Alaska
NSAC1 Browse Data Browse PlotsCentral Facility, Barrow AK
NSAC2 Browse DataCentral Facility, Atqasuk AK retired
Southern Great Plains
SGPC1 Browse DataCentral Facility, Lamont, OK
SGPE1 Browse DataLarned, KS (Extended) retired
SGPE3 Browse DataLeRoy, KS (Extended) retired
SGPE7 Browse Data Browse PlotsElk Falls, KS (Extended)
SGPE8 Browse DataColdwater, KS (Extended) retired
SGPE9 Browse Data Browse PlotsAshton, KS (Extended)
SGPE10 Browse DataTyro, KS (Extended) retired
SGPE11 Browse Data Browse PlotsByron, OK (Extended)
SGPE12 Browse Data Browse PlotsPawhuska, OK (Extended)
SGPE13 Browse Data Browse PlotsLamont, OK (Extended)
SGPE15 Browse DataRingwood, OK (Extended)
SGPE16 Browse Data Browse PlotsVici, OK (Extended) retired
SGPE22 Browse DataCordell, OK (Extended)
SGPE24 Browse Data Browse PlotsCyril, OK (Extended) retired
SGPE25 Browse DataSeminole, OK (Extended) retired
SGPE27 Browse Data Browse PlotsEarlsboro, OK (Extended) retired
SGPE31 Browse Data Browse PlotsAnthony, KS (Extended)
SGPE32 Browse Data Browse PlotsMedford, OK (Extended)
SGPE33 Browse Data Browse PlotsNewkirk, OK (Extended)
SGPE34 Browse Data Browse PlotsMaple City, KS (Extended)
SGPE35 Browse Data Browse PlotsTryon, OK (Extended)
SGPE36 Browse Data Browse PlotsMarshall, OK (Extended)
SGPE38 Browse Data Browse PlotsOmega, OK (Extended)
Tropical Western Pacific
TWPC1 Browse DataCentral Facility, Manus I., PNG retired
ARM Mobile Facility
FKBM1 Browse Data Browse PlotsBlack Forest, Germany retired
GANM1 Browse Data Browse PlotsGan Airport, Gan Island, Maldives retired
GRWM1 Browse Data Browse PlotsGraciosa Island, Azores, Portugal retired
HFEM1 Browse DataShouxian, Anhui, China retired
MAOM1 Browse DataManacapuru, Amazonas, Brazil; AMF1
OLIM1 Browse Data Browse PlotsOliktok Point, Alaska
PGHM1 Browse Data Browse PlotsARIES Observatory, Nainital, Uttarkhand, India retired
PVCM1 Browse Data Browse PlotsHighland Center, Cape Cod MA; AMF 1
PYEM1 Browse Data Browse PlotsPoint Reyes, CA retired
SBSM1 Browse DataSteamboat Springs CO, Valley Site retired
TMPM1 Browse DataU. of Helsinki Research Station (SMEAR II), Hyytiala, Finland; AMF2
 retired = Originating instrument has been retired at this location


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

Brian Ermold
Pacific Northwest National Laboratory
(509) 375-2277

Connor Flynn
Pacific Northwest National Laboratory
(509) 375-2041