A Daily-Filtered Penticton F10.7 cm Solar Radio Flux Data Product to Support the New NOAA/NCEI Solar Irradiance Climate Data Record

The solar radio flux at 10.7 cm (2.8 GHz) is a disk-integrated measure of the Sun’s chromospheric emission with an added coronal component. A record of the solar radio flux, corrected for the changing distance between the Sun and the Earth and adjusted to the mean Sun-Earth distance, has been monitored since 1947 by the National Research Council of Canada. Since 1991, these operational measurements have been made by the Dominion Radio Astrophysical Observatory (DRAO) located near Penticton, British Columbia. The F10.7 cm solar radio flux is an excellent indicator of solar activity that has been shown to track the extreme ultraviolet (EUV) irradiance and therefore has applications in forecasting space weather and modeling the extreme ultraviolet (EUV) solar irradiance. For example, the new version 3 of the NOAA National Centers for Environmental Information (NCEI Solar Irradiance Climate Data Record (CDR), that will be publicly released in August 2024, will operationally produce estimates of solar irradiance from the year 1610 to the present day over a broader spectral range from the extreme ultraviolet through the far-infrared (~0 - 200,000 nm) than the current NOAA/NCEI Solar Irradiance CDR V2 (spanning 115 - 100,000 nm). We will utilize the DRAO F10.7 cm solar radio flux, subset to a single daily value and filtered for radio bursts, to produce daily EUV irradiance estimates for the NOAA/NCEI CDR V3 that supports both the space weather and climate modeling research communities. In this work, we describe our methodology to produce a single, daily F10.7 cm solar radio flux value from the thrice-daily DRAO radio telescope observations each made over a 1-hour period. Furthermore, we describe our approach to identifying and removing contributions over second-to-minute time scales from radio “bursts” that can impact the daily value. Lastly, we will show time series and correlation comparisons of our daily product to independent F10.7 cm data products, model estimates, and solar irradiance at Lyman alpha wavelengths.