gov.noaa.ngdc.stp.solar:G00216WDC/STP, Boulder > World Data Center for Solar-Terrestrial Physics, BoulderWDC/Solar Radion Emissions > World Data Center for Solar Radio Emissions, Japan1973Scientists monitor the structure of the solar corona, the outer most regions of the Sun's atmosphere, using radio waves. The surface of the Sun is 6,000 degrees Kelvin, while the high corona can reach several million degrees Kelvin. Solar radio emissions at different frequencies allow us to observe radiation from different heights in the atmosphere. The lower the frequency, the higher the height of origin. The frequency, like the electron density, decreases uniformly outwards: 245 MHz originates high in the corona, while 15,400 MHz originates in the low corona. The 5 MHz emission corresponds to about 10 solar radii height. For a detailed review, see McLean and Labrum (1985)Solar Radiophysics.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.To provide long-term scientific data stewardship for the Nation's geophysical data, ensuring quality, integrity, and accessibility.19470214UnknownUnknownIn workmonthlyNASA/Global Change Master Directory (GCMD) Earth Science KeywordsEarth Science > Sun-Earth Interactions > Solar Activity > Solar Radio Wave EmissionsUncontrolled KeywordsOttawa 10.7 cm FluxQuiet Sun FluxSlowly Varying ComponentSolar PhysicsSolar Radio FluxNASA/GCMD Location KeywordsSpace > Solar Region > ChromosphereSpace > Solar Region > CoronaRestriction Code: otherRestrictions; DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of CommerceSolar Data Managerphysical and mailing NOAA/NESDIS/NGDC E/GC2 325 Broadway BoulderCO80305303.497.6133 or 303.497.6323solar.ngdc@noaa.govUnknown 20111117Solar Data ManagerDOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commercemailing and physical NOAA/NESDIS/NGDC E/GC2 325 Broadway BoulderCO80305303.497.6133 or 303.497.6323solar.ngdc@noaa.govContent Standard for Digital Geospatial Metadata: Extensions for Remote Sensing MetadataFGDC-STD-012-2002