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Vertical Soundings (Ionograms) 


Definition of Structure


Ionospheric Indices (defined)

Ionosphere Program at NCEI

The content and data referenced on this page will be moving. A permanent redirect will be put in place during the summer months of 2024. See link.


The Ionospheric Physics Group of NCEI operates the Ionosphere portion of the World Data Service for Geophysics, which seeks out and archives data, data products, and information related to the Ionosphere. Though our focus is ever expanding, much of the current effort at NCEI is in the Ionospheric Vertical Incidence Sounding discipline. NCEI leads the effort to collect, quality control, and distribute a unified dataset of vertical sounding scaled parameters using modern internet based dissemination services.

The D-Region Absorption Prediction Product, Release 2 (D-RAP2) is available at NCEI and SWPC. Retrospective D-RAP2 product outputs can be found at NCEI's D-Region Absorption Prediction Products

  • A global map of the highest HF frequencies affected by a 1 dB attenuation, estimated recovery time - PNG
  • A north and/or south pole map of the highest frequencies affected by a 10dB attenuation, estimated recovery time - PNG graphics file
  • ASCII tabular values of total absorption at 10 MHz - text file that also includes estimated recovery time

Ionosphere Technology Demonstration of

Ionosphere Data Archives

  • WDCB in Moscow, WDC1 in England, WDC2 in Japan, & IPS in Australia.
  • International Union Of Radio Science (URSI )
  • University of Massachusetts Lowell Center for Atmospheric Research (UMLCAR) Didbase