The structure of the solar corona, the outermost regions of the Sun's atmosphere, can be monitored using radio waves (100’s of MHz to 10’s of GHz). Variations in the radio wave spectrum reveal characteristics of the corona and upper chromosphere in terms of altitude profile for the local plasma temperature, density and magnetic field. Typically, the lower the frequency, the higher the height of origin.
Radio bursts are associated with solar flares. The signal arrival time delay at Earth of the different radio frequencies during burst events is due to the outward movement of the source. Large bursts last 10 to 20 minutes on average. Longer radio noise storms of persistent and variable high levels of radiation originate in sunspot groups, areas of large, intense magnetic fields.
NOAA NCEI has solar radio legacy datasets from multiple sources over many decades, including the United States Air Force (USAF) Radio Solar Telescope Network (RSTN) stations. RSTN uses four widely spaced antennae to observe the Sun between 18 MHz and 15 GHz to measure solar radio bursts: Palehua (Ka'ena Point), Learmoth, San Vito and Sagamore Hill. The data presented here are provided, ‘as is,’ and in most cases the linked documentation is the entirety of available information. In some cases, older data may also be found in the Space Weather Legacy Print Publications.
Questions and comments may be directed to ncei.info@noaa.gov
Radio Bursts
Radio bursts are associated with solar flares. The signal arrival time delay at Earth of the different radio frequencies during burst events is due to the outward movement of the source. Large bursts last 10 to 20 minutes on average. Longer radio noise storms of persistent and variable high levels of radiation originate in sunspot groups, areas of large, intense magnetic fields.
- Radio bursts from Culgoora Observatory: .txt files (2011-2014)
- Radio bursts at fixed frequencies, RSTN: .txt files (1960 - 2010) | Read me
- Radio bursts, spectral data, RSTN: .txt files (1967 - 2011)
- Type II from Weissenau station: .pdf and .txt files (1966 - 1987)
- Type II from RSTN: .txt files (1967 - 2009)
- Radio bursts summary, RSTN: .txt files (2012)
Daily Full Solar Disk Radio Flux Measurements
Measurements taken at local noon at various solar radio observatories. Observatories include facilities in the Solar Electro-Optical Network (SEON, RSTN, SOON), Krakow, and Penticton. Date coverage and observed frequencies vary.
- Noontime Radio flux, multiple stations, including RSTN: .txt files (1947 - 2019)
- Daily mean Radio flux, multiple stations from IAU "Quarterly Bulletin of Solar Activity" and Ottawa: .txt files (1949 - 1986) Data source: NOAA/ESDIM and NASA/SPDS data rescue projects.
National Research Council Canada, specifically the Penticton observatory, is the current worldwide provider of F10.7 data.
Daily Maps of Solar Radio Emissions
- Nobeyama Solar Radio Observatory(2002-2011)
- Wilcox Solar Observatory (Stanford) (1962-1973)
- These maps are in text format.
- See the documentation for how to interpret the text table into maps.