Ionosonde Stations

Ionograms are recorded tracings of reflected high frequency radio pulses generated by an ionosonde. Unique relationships exist between the sounding frequency and the ionization densities which can reflect it. As the sounder sweeps from lower to higher frequencies, the signal rises above the noise of commercial radio sources and records the return signal reflected from the different layers of the ionosphere. These echoes form characteristic patterns of
"traces" that comprise the ionogram. Radio pulses travel more slowly within the ionosphere than in free space, therefore, the apparent or "virtual" height is recorded instead of a true height. For frequencies approaching the level of maximum plasma frequency in a layer, the virtual height tends to infinity, because the pulse must travel a finite distance at effectively zero speed. The frequencies at which this occurs are called the critical frequencies. Characteristic values
of virtual heights (designated as h'E, h'F, and h'F2, etc.) and critical frequencies (designated as foE, foF1, and foF2, etc.) of each layer are scaled, manually or by computer, from these ionograms. Typically, an ionosonde station obtains one ionogram recording every 15 minutes. When the scaling is done manually only the hourly recordings are routinely reduced to numerical data. Modern ionosondes with computer-driven automatic scaling procedures routinely scale all the
ionograms recorded. The resulting numerical values, along with the original ionograms and station reports, are archived at five World Data Centers (WDCs) for Ionosphere. The ionosphere is divided into four broad regions called D,E, F, and topside. These regions may be further divided into several regularly occurring layers, such as F1 or F2.D Region: The region between about 75 and 95km above the Earth in which the relatively weak) ionization is mainly responsible for
absorption of high-frequency radio waves. E Region: The region between about 95 and 150km above the Earth that marks the height of the regular daytime E layer. Other subdivisions isolating separate layers of irregular occurrence within this region are also labeled with an E prefix, such as the thick layer, E2, and a highly variable thin layer, Sporadic E. Ions in this region are mainly O2+. F Region: The region above about 150km in which the important reflecting layer, F2, is
found. Other layers within this region are also described using the prefix F, such as a temperate-latitude regular stratification, F1, and a low-latitude, semi-regular stratification, F1.5. Ions in the lower part of the F layer are mainly NO+ and are predominantly O+ in the upper part. The F layer is the region of primary interest for radio communications.
Cite this dataset when used as a source.
  • ID not available.
gov.noaa.ngdc.stp.ionosonde:G10145
Download Data
Other Access
Distribution Formats
  • via ftp: SAO, EDP GIF, PNG, MMM, 16C, RSF, SDF, GRM, DFT and SKY via Spidr: ASCII, XML Matlab
Distributor Justin Mabie
Space and Terrestrial Weather Specialist
DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
(303) 497-6135
Justin.Mabie@noaa.gov
Dataset Point of Contact Justin Mabie
Space and Terrestrial Weather Specialist
DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
(303) 497-6135
Justin.Mabie@noaa.gov
Time Period 1958-01-01 to Present
Spatial Bounding Box Coordinates
West:-180
East:180
South:-90
North:90
Spatial Coverage Map
General Documentation
Publication Dates
  • publication: 1958-01-01
Dataset Progress Status Under development - data is currently in the process of being created
Data Update Frequency Daily
Supplemental Information
Every Ionosonde station has it's own metadata record in Spidr and also in the Ionosonde Record Set here in the NMMR
Purpose To produce Ionograms
Use Limitations
  • While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, NOAA cannot assume liability for any damages caused by any errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.
Originators
  • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
Publishers
  • NOAA National Centers for Environmental Information
Theme keywords NASA/GCMD Earth Science Keywords
  • Sun-Earth >Interactions >Solar Energetic Particle Properties >Particle Density >Electron Density height Profile
  • Spectral/Engineering >Radar >Radar Reflectivity
Data Center keywords Global Change Master Directory (GCMD) Data Center Keywords
  • 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
Place keywords NASA/GCMD Location Keywords
  • Vertical Location > Ionosphere
Project keywords Global Change Master Directory (GCMD) Project Keywords
  • ICSU-WDS > International Council for Science - World Data System
Use Constraints
  • Use Constraints: None
Access Constraints
  • Access Constraints: None
Fees
  • None
Lineage information for:repository
Processing Steps
  • 2015-04-22T00:00:00 -NOAA created the National Centers for Environmental Information (NCEI) by merging NOAA's National Climatic Data Center (NCDC), National Geophysical Data Center (NGDC), and National Oceanographic Data Center (NODC), including the National Coastal Data Development Center (NCDDC), per the Consolidated and Further Continuing Appropriations Act, 2015, Public Law 113-235. NCEI launched publicly on April 22, 2015.
Last Modified: 2015-09-18
For questions about the information on this page, please email:Justin.Mabie@noaa.gov