swfluxanal: Shortwave Flux Analysis

swfluxThe SW (shortwave) Flux Analysis VAP applies a clear-sky detection and fitting technique (Long and Ackerman 2000) to data from broadband SW radiometers located at the Southern Great Plains site. This technique uses hemispheric, broadband total- and diffuse-shortwave irradiance measurements to identify clear-sky periods using the known characteristics of typical clear-sky irradiance time series. These clear-sky estimates are then used to infer the effect of cloudiness on the measured downwelling SW at 1-minute resolution for daylight hours. The 1-minute resolution analysis also includes data quality assessment that goes beyond standard min/max/delta and component comparison testing. The SW Flux Analysis VAP also uses a technique (Long et al. 1999) to infer average fractional sky cover at 15-minute resolution for solar elevation angles 10° or greater.

For more details, see The Shortwave (SW) Clear-Sky Detection and Fitting Algorithm: Algorithm Operational Details and Explanations technical report.


  • Fixed
  • AMF1
  • AMF2
  • AMF3


brs: Broadband Radiometer Station

siros: Solar and Infrared Radiation Observation Station Instruments

sirs: Solar and Infrared Radiation Station

skyrad: Sky Radiometers on Stand for Downwelling Radiation

Related Publications


Burleyson CD, CN Long, and JM Comstock. 2015. "Quantifying Diurnal Cloud Radiative Effects by Cloud Type in the Tropical Western Pacific." Journal of Applied Meteorology and Climatology, 54(6), 10.1175/JAMC-D-14-0288.1. ONLINE.


Wu W, Y Liu, MP Jensen, T Toto, MJ Foster, and CN Long. 2014. "A comparison of multiscale variations of decade-long cloud fractions from six different platforms over the Southern Great Plains in the United States." Journal of Geophysical Research: Atmospheres, 119(6), 10.1002/2013JD019813.


Sivaraman C. 2012. ARM Climate Research Facility Quarterly Value-Added Product Report First Quarter: October 01-December 31, 2011. U.S. Department of Energy. DOE/SC-ARM-12-002.

Long CN, LD Riihimaki, and LK Berg. 2012. Near-term Forecasting of Solar Total and Direct Irradiance for Solar Energy Applications. Presented at Fall American Geophysical Union Meeting. San Francisco, CA.

Sivaraman C. 2012. ARM Climate Research Facility Quarterly Value-Added Product Report Fourth Quarter: July 1–September 30, 2012. U.S. Department of Energy. DOE/SC-ARM-12-022.


Roesch A, M Wild, A Ohmura, EG Dutton, CN Long, and T Zhang. 2011. "Assessment of BSRN radiation records for the computation of monthly means." Atmospheric Measurement Techniques, 4(2), 10.5194/amt-4-339-2011.

Liu Y, W Wu, MP Jensen, and T Toto. 2011. "Relationship between cloud radiative forcing, cloud fraction and cloud albedo, and new surface-based approach for determining cloud albedo." Atmospheric Chemistry and Physics, 11(14), doi:10.5194/acp-11-7155-2011.

Berg LK, EI Kassianov, CN Long, and DL Mills. 2011. "Surface summertime radiative forcing by shallow cumuli at the ARM SGP." Journal of Geophysical Research – Atmospheres, 116, D01202, 10.1029/2010JD014593.


Zhang Y, CN Long, WB Rossow, and EG Dutton. 2010. "Exploiting diurnal variations to evaluate the ISCCP-FD flux calculations and radiative-flux-analysis-processed surface observations from BSRN, ARM, and SURFRAD." Journal of Geophysical Research, 115(D15), D00K11, 10.1029/2009JD012743.

Foster MJ and DE Veron. 2010. "Employing Cluster Analysis to Detect Significant Cloud 3D RT Effect Indicators." Journal of the Atmospheric Sciences, 67(7), 10.1175/2010JAS3414.1.

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