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Sudden Ionospheric Disturbances (SID)
Sudden ionospheric disturbances (SID) are caused by solar flare enhanced X-rays in the 1 to 10 angstrom range. Solar flares can produce large increases of ionization in the D-region of the ionosphere over the daylit hemisphere of the Earth. SID's typically begin simultaneously or a few minutes after the start of a solar flare, and can have a time duration somewhat longer than the flare with a rise time more rapid than the decay time.Types of SIDs are SCNA--sudden cosmic noise absorption is a riometer-detected sudden daytime absorption increases; SEA--sudden enhancement of atmospherics are increases in signal strength on wideband equipment operated in the VLF, 10 to 50 KHz frequency range; SES--sudden enhancement of signal, observed on VLF frequencies in the 15 to 50 KHz range are nearly identical to SEA except that the receivers are narrow-band receivers designed to pick up man-made VLF transmission. Like SEA, signal strength increase is the SID indicator; SFD--sudden frequency deviation is the sudden increase of high frequency radiowaves which reaches a peak, and then decays back to the transmitting frequency; SPA--sudden phase anomaly is an abrupt shift in the phase of a radio signal on VLF frequencies received by ionospheric reflection; SWF--short wave fadeouts are abrupt decreases of radio signal strength observed at VLF frequencies.Tables of SIDs include the date; beginning, maximum and ending times; type of SID; importance on a scale of 1- to 3+ and the corresponding solar flare, if known.
Complete Metadata
| @type | dcat:Dataset |
|---|---|
| accessLevel | non-public |
| accrualPeriodicity | R/P1M |
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| description | Sudden ionospheric disturbances (SID) are caused by solar flare enhanced X-rays in the 1 to 10 angstrom range. Solar flares can produce large increases of ionization in the D-region of the ionosphere over the daylit hemisphere of the Earth. SID's typically begin simultaneously or a few minutes after the start of a solar flare, and can have a time duration somewhat longer than the flare with a rise time more rapid than the decay time.Types of SIDs are SCNA--sudden cosmic noise absorption is a riometer-detected sudden daytime absorption increases; SEA--sudden enhancement of atmospherics are increases in signal strength on wideband equipment operated in the VLF, 10 to 50 KHz frequency range; SES--sudden enhancement of signal, observed on VLF frequencies in the 15 to 50 KHz range are nearly identical to SEA except that the receivers are narrow-band receivers designed to pick up man-made VLF transmission. Like SEA, signal strength increase is the SID indicator; SFD--sudden frequency deviation is the sudden increase of high frequency radiowaves which reaches a peak, and then decays back to the transmitting frequency; SPA--sudden phase anomaly is an abrupt shift in the phase of a radio signal on VLF frequencies received by ionospheric reflection; SWF--short wave fadeouts are abrupt decreases of radio signal strength observed at VLF frequencies.Tables of SIDs include the date; beginning, maximum and ending times; type of SID; importance on a scale of 1- to 3+ and the corresponding solar flare, if known. |
| distribution |
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|
| identifier | gov.noaa.ngdc.stp.ionosphere:G00581 |
| issued | 1958-01-01T00:00:00.000+00:00 |
| keyword |
[
"EARTH SCIENCE > Sun-earth Interactions > Solar Activity > Solar Radio Waves",
"Solar Physics",
"Short Wave Fade",
"Sudden Phase Anomaly",
"Solar Flare Atmospherics",
"D Region",
"Soft X-Rays",
"ICSU-WDS > International Council for Science - World Data System",
"Ionosphere",
"DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce",
"DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce"
]
|
| landingPage | ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/Sudden_Ionospheric_Disturbances |
| language |
[]
|
| license | https://creativecommons.org/publicdomain/zero/1.0/ |
| modified | 1958-01-01T00:00:00.000+00:00 |
| publisher |
{
"name": "NOAA National Centers for Environmental Information",
"@type": "org:Organization"
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|
| rights | otherRestrictions |
| spatial | 180.0,-90.0,-180.0,90.0 |
| temporal | 1958-01-01T00:00:00+00:00/1958-01-01T00:00:00+00:00 |
| title | Sudden Ionospheric Disturbances (SID) |
