VAP : Correction of Diffuse Shortwave Measurements (DIFFCOR)

Instrument Categories
Derived Quantities and Models

The DIFFCORR1DUTT VAP uses two techniques to correct shortwave (SW) data during daytime hours, using information from a collocated pyrgeometer. First, the detector-only correction technique uses data in the form of irradiance loss from the pyrgeometer detector. Second, the full-correction technique uses information from collocated pyrgeometer detector data, plus the difference between the case and dome temperatures. Both techniques collect nighttime data with corresponding pyranometer infrared-loss data. The fitting routine for detection and correction consists of two modes: dry and moist. Each mode is detected separately in the nighttime data and applied separately during the daytime. The correction to the SW daylight data is applied only if the data pass quality analysis checks. The DiffCorr1Dutt VAP output files contain a best estimate of the downwelling SW, and a best estimate of the diffuse SW. In addition, the output files contain other useful values, such as an estimate of the clear-sky Rayleigh diffuse SW amount, and standard surface meteorological measurements.

For more details, see

Output Products

  • siros1dutt : Solar and Infrared Radiation Observing Station (SIROS): 1-min data with Dutton correction
  • sirs1dutt : SIRS: derived, correction of downwelling shortwave diffuse hemispheric measurements using Dutton and full algorithm

Primary Measurements

The following measurements are those considered scientifically relevant.


North Slope Alaska
NSAC1Browse DataCentral Facility, Barrow AK
NSAC2Browse DataCentral Facility, Atqasuk AK
Southern Great Plains
SGPC1Browse DataCentral Facility, Lamont, OK
SGPE1Browse DataLarned, KS
SGPE2Browse DataHillsboro, KS (Extended)
SGPE3Browse DataLeRoy, KS
SGPE4Browse DataPlevna, KS
SGPE5Browse DataHalstead, KS
SGPE6Browse DataTowanda, KS
SGPE7Browse DataElk Falls, KS
SGPE8Browse DataColdwater, KS
SGPE9Browse DataAshton, KS
SGPE10Browse DataTyro, KS
SGPE11Browse DataByron, OK
SGPE12Browse DataPawhuska, OK
SGPE13Browse DataLamont, OK (Extended)
SGPE15Browse DataRingwood, OK
SGPE16Browse DataVici, OK (Extended)
SGPE18Browse DataMorris, OK (Extended)
SGPE19Browse DataEl Reno, OK
SGPE20Browse DataMeeker, OK (Extended)
SGPE21Browse DataOkmulgee, OK
SGPE22Browse DataCordell, OK
SGPE24Browse DataCyril, OK
SGPE25Browse DataSeminole, OK
Tropical Western Pacific
TWPC1Browse DataCentral Facility, Manus I., PNG
TWPC2Browse DataCentral Facility, Nauru Island


Laura Riihimaki
(509) 375-6406