VAP : Cloud Optical Properties from MFRSR Using Min Algorithm (MFRSRCLDOD)

Instrument Categories
Aerosols, Radiometric

The mfrsrcldod1min value-added product produces cloud optical depth for overcast liquid clouds using narrowband irradiance measurements from the multifilter rotating shadowband radiometer (MFRSR). If liquid water path is available from the microwave radiometer (MWR), then effective radius is also derived; otherwise a default effective radius of 8.0 um is assumed.

The mfrsrcldod1min value-added product (VAP) obtains cloud optical depth and effective radius using a retrieval algorithm developed by Min and Harrison (1996). A look-up table of total transmittance at 415 nm is calculated using a radiative transfer model for a range of cloud water path, effective radius, optical depth, and solar zenith angles. The measured transmittance (derived from the MFRSR measurements and the Langley VAP), liquid water path, and solar zenith angle and an assumed surface albedo are input to the algorithm. The optical depth and effective radius are then retrieved by interpolating across the look-up table. The 1-sigma uncertainties in the optical depth and effective radius are also estimated by propagating uncertainty in the input irradiance, liquid water path, and surface albedo.

Quality control (qc) flags have been added to the VAP output. The cloud retrievals in the current version of this VAP are only valid for overcast, optically thick liquid clouds. Cloud fraction from the shortwave flux analysis VAP is used to identify and flag cases with cloud fraction less than 0.9. Retrievals with optical depth < 7 are flagged as indeterminate. Cloud base height is also included in the output files (when available at a given site) that users can determine whether clouds are likely to be liquid or ice, which depends on the site and season.

The MFRSRCLOD VAP was significantly updated in 2011. Details of the changes and differences with previous versions of the data are available in the VAP report "‘Changes to MFRSRCLDOD1MIN Datastream".

The Langley VAP, which is an input to MFRSRCLDOD, was updated in 2010. Details of how that affects the processing of the MFRSRCLDOD will be available in an upcoming technical report.

For more details, see Cloud Optical Properties from the Multi-Filter Shadowband Radiometer (MFRSRCLDOD) An ARM Value-Added Product technical report.


Output Products

  • mfrsrcldod1min : Derived: Cloud Optical Properties from MFRSR, MWR, Langley Analysis

Primary Measurements

The following measurements are those considered scientifically relevant.


North Slope Alaska
NSAC1 Browse DataCentral Facility, Barrow AK
Southern Great Plains
SGPC1 Browse DataCentral Facility, Lamont, OK
SGPE1 Browse DataLarned, KS retired
SGPE2 Browse DataHillsboro, KS (Extended) retired
SGPE3 Browse DataLeRoy, KS retired
SGPE4 Browse DataPlevna, KS retired
SGPE5 Browse DataHalstead, KS retired
SGPE6 Browse DataTowanda, KS retired
SGPE7 Browse DataElk Falls, KS retired
SGPE8 Browse DataColdwater, KS retired
SGPE9 Browse DataAshton, KS
SGPE10 Browse DataTyro, KS retired
SGPE11 Browse DataByron, OK
SGPE12 Browse DataPawhuska, OK
SGPE13 Browse DataLamont, OK (Extended)
SGPE15 Browse DataRingwood, OK
SGPE16 Browse DataVici, OK (Extended) retired
SGPE18 Browse DataMorris, OK (Extended) retired
SGPE19 Browse DataEl Reno, OK retired
SGPE20 Browse DataMeeker, OK (Extended) retired
SGPE22 Browse DataCordell, OK retired
SGPE24 Browse DataCyril, OK retired
SGPE25 Browse DataSeminole, OK retired
SGPE27 Browse DataEarlsboro, OK retired
SGPE31 Browse DataAnthony, KS
SGPE32 Browse DataMedford, OK
SGPE33 Browse DataNewkirk, OK
SGPE34 Browse DataMaple City, KS
SGPE35 Browse DataTryon, OK
SGPE36 Browse DataMarshall, OK
SGPE37 Browse DataWaukomis, OK
SGPE38 Browse DataOmega, OK
Tropical Western Pacific
TWPC1 Browse DataCentral Facility, Manus I., PNG retired
TWPC2 Browse DataCentral Facility, Nauru Island retired
TWPC3 Browse DataCentral Facility, Darwin, Australia retired
ARM Mobile Facility
FKBM1 Browse DataBlack Forest, Germany retired
GANM1 Browse DataGan Airport, Gan Island, Maldives retired
GRWM1 Browse DataGraciosa Island, Azores, Portugal retired
MAOM1 Browse DataManacapuru, Amazonas, Brazil; AMF1
PGHM1 Browse DataARIES Observatory, Nainital, Uttarkhand, India retired
PVCM1 Browse DataHighland Center, Cape Cod MA; AMF 1 retired
PYEM1 Browse DataPoint Reyes, CA retired
 retired = Originating instrument has been retired at this location


Yan Shi
Pacific Northwest National Laboratory
(509) 375-6858

Qilong Min
State University of New York, Albany
Science Sponsor
(518) 437-8742

Laura Riihimaki
Pacific Northwest National Laboratory
(509) 375-6406