Solar Radio
Scientists monitor the structure of the solar corona, the outer most regions of the Sun's atmosphere, using radio waves (100’s of MHz to 10’s of GHz). Variations in the
radiowave 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 then the higher the height of origin. The frequency, like the solar electron density, decreases uniformly outwards with 245 MHz originating high in the corona whereas 15,400 MHz
originates in the low corona. Radio bursts are associated with solar flares. The delay at Earth of the different radio frequencies during burst events is due to the outward movement of the source.
Bursts can have temperatures of 10xE12 degrees Kelvin. 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. These storms are strongly circularly polarized due to the intense magnetic fields. The microwave wavelength 2800 MHz daily radio flux
correlates highly with the daily sunspot number and the two databases are used interchangeably. The 2800 MHz, or 10.7 cm, responds to the same conditions that produce changes in the visible and
X-ray wavelengths. Schmahl and Kundu (1995) find that the solar radio fluxes in the spectral range 1000-9400 MHz correlate well with the total solar irradiance. The intermediate frequencies
(at 2800 and 3750 MHz) are produced mainly by free-free gyroresonance emission from sunspot structures, while 1000 and 9400 MHz flux are produced mainly by free-free processes from structures
associated with plages. They can distinguish plage-associated emission from spot-associated emission in the time series of microwave flux, both contributing opposing effects on the total
solar irradiance.
radiowave 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 then the higher the height of origin. The frequency, like the solar electron density, decreases uniformly outwards with 245 MHz originating high in the corona whereas 15,400 MHz
originates in the low corona. Radio bursts are associated with solar flares. The delay at Earth of the different radio frequencies during burst events is due to the outward movement of the source.
Bursts can have temperatures of 10xE12 degrees Kelvin. 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. These storms are strongly circularly polarized due to the intense magnetic fields. The microwave wavelength 2800 MHz daily radio flux
correlates highly with the daily sunspot number and the two databases are used interchangeably. The 2800 MHz, or 10.7 cm, responds to the same conditions that produce changes in the visible and
X-ray wavelengths. Schmahl and Kundu (1995) find that the solar radio fluxes in the spectral range 1000-9400 MHz correlate well with the total solar irradiance. The intermediate frequencies
(at 2800 and 3750 MHz) are produced mainly by free-free gyroresonance emission from sunspot structures, while 1000 and 9400 MHz flux are produced mainly by free-free processes from structures
associated with plages. They can distinguish plage-associated emission from spot-associated emission in the time series of microwave flux, both contributing opposing effects on the total
solar irradiance.
Dataset Citation
Cite this dataset when used as a source.
Dataset Identifiers
- solarFeatures
ISO 19115-2 Metadata
gov.noaa.ngdc.stp.solar:solar-features_solar-features_solar-radio
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Distribution Formats |
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Distributor | William Denig DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce (303) 497-6323 solar.ngdc@noaa.gov |
Dataset Point of Contact | William Denig DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce (303) 497-6323 solar.ngdc@noaa.gov |
Coverage Description | Data assembled from data provided by various solar observatories located worldwide. |
Time Period | 1955-07-01 to 2010-11-24 |
Spatial Bounding Box Coordinates |
West: -180
East: 180
South: -90
North: 90
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Spatial Coverage Map |
General Documentation |
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Publication Dates |
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Dataset Progress Status | Under development - data is currently in the process of being created |
Data Update Frequency | Annually |
Supplemental Information | Collection consists of tabular lists and information related to solar features |
Purpose | To provide scientific data stewardship of solar-terrestrial datasets in compliance with NOAA Administrative Order (NAO) 212-15, "Management of Environmental and Geospatial Data and Information", dated 04 Nov 10. Scientific Data Stewardship includes the Archive, Access, and Assessment (AAA) of operational and related solar and space environmental datasets. |
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Theme keywords |
NASA/GCMD Earth Science Keywords; Olsen, L.M., G. Major, K. Shein, J. Scialdone, R. Vogel, S. Leicester, H. Weir, S. Ritz, T. Stevens, M. Meaux, C.Solomon, R. Bilodeau, M. Holland, T. Northcutt, R. A. Restrepo, 2007 . NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 6.0.0.0.0.
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Data Center keywords |
Global Change Master Directory (GCMD) Data Center Keywords
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Platform keywords |
NASA/GCMD Platform Keywords; Olsen, L.M., G. Major, K. Shein, J. Scialdone, R. Vogel, S. Leicester, H. Weir, S. Ritz, T. Stevens, M. Meaux, C.Solomon, R. Bilodeau, M. Holland, T. Northcutt, R. A. Restrepo, 2007 . NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 6.0.0.0.0.
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Instrument keywords |
NASA/GCMD Instrument Keywords; Olsen, L.M., G. Major, K. Shein, J. Scialdone, R. Vogel, S. Leicester, H. Weir, S. Ritz, T. Stevens, M. Meaux, C.Solomon, R. Bilodeau, M. Holland, T. Northcutt, R. A. Restrepo, 2007 . NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 6.0.0.0.0.
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Place keywords |
NASA/GCMD Location Keywords; Olsen, L.M., G. Major, K. Shein, J. Scialdone, R. Vogel, S. Leicester, H. Weir, S. Ritz, T. Stevens, M. Meaux, C.Solomon, R. Bilodeau, M. Holland, T. Northcutt, R. A. Restrepo, 2007 . NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 6.0.0.0.0.
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Project keywords |
Global Change Master Directory (GCMD) Project Keywords
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Lineage Statement | Authoritative data provided by the NOAA National Geophysical Data Center. |
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Last Modified: 2015-10-02
For questions about the information on this page, please email: solar.ngdc@noaa.gov
For questions about the information on this page, please email: solar.ngdc@noaa.gov