Solar Flux Assessment¶

The quality of surface-based measurements are generally considered more accurate than satellite-derived values. However, measurement uncertainties from instrument calibration drift, operational uncertainties, instrumental changes, or data gaps are often unknown or unreported for many surface data sets. In 1989, the World Climate Research Program estimated "end-to-end" uncertainties for most routine-operation solar radiation ground sites in the range from 6% to 12%. Specialized high-quality research sites such as those in the Baseline Surface Radiation Network (BSRN) are estimated to be more accurate by a factor of two.

GEWEX SRB 4-IP¶

Validation of GEWEX SRB 4-IP SW surface downward parameters has been performed by the GEWEX SRB team using land and ocean based observations. A summary of this validation at different time scales is presented at GEWEX SRB Validation. While the validation period is longer than the data available through POWER, the statistics obtained are applicable here.

A summary of the daily mean all-sky shortwave (SW) radiative fluxes on a horizontal surface from NASA’s GEWEX SRB Release 4.0 validated against values from BSRN sites is presented below.

CERES SYN1Deg¶

A summary of all-sky shortwave (SW) radiative fluxes on a horizontal surface from NASA’s CERES SYN1deg (Ed4.1) validated against BSRN site observations is presented below. The monthly and daily validations are computed for April 2000 through December 2020, while hourly validation covers Jan., Apr., Jul., and Oct. 2019. An in-depth assessment of hourly solar irradiance for SYN1Deg is also presented on the Solar Correction page.

CERES FLASHFlux¶

A summary of all-sky shortwave (SW) radiative fluxes on a horizontal surface from NASA’s FLASHFlux 4A validated against values from BSRN sites for Jan., Apr., Jul., and Oct. 2019 is presented below.