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Vertical Soundings (Ionograms) 


Definition of Structure


Ionospheric Related Models

Ionospheric Indices (defined)

Scintillation Predictions

HF Radio Interest

Ionosphere Program at NGDC

The Ionospheric Physics Group of NGDC operates the Ionosphere portion of the World Data Center for Solar-Terrestrial Physics, Boulder, 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 NGDC is in the Ionospheric Vertical Incidence Sounding discipline. NGDC is currently leading the effort to collect, quality control, and distribute a unified dataset of vertical sounding scaled parameters using modern internet based dissemination services.

NewSign-up for Email Alerts
Subscribers to this list will receive occasional updates regarding ionosonde data and models at NOAA NGDC. The models include US-TEC, D-RAP and FIRST.

NewIonosonde Inventory
NGDC has a new ionosonde inventory for individual soundings. The system provides a fully functional REST interface. The URL is user friendly and can be modified easily to suite your needs. Or you may use the form driven wizard "Generate Hourly Summary". If the inventory shows we have online data, then you may retrieve it by clicking the day of year link for the day of interest.
NGDC's ionosonde datasets are shared with other data centers, contributors, and customers via these mechanisms: SPIDR, http and ftp.

New — The D-Region Absorption Prediction Product, Release 2 (D-RAP2) is now available at NGDC and SWPC. The following retrospective D-RAP2 product outputs can be found at NGDC's D-Region Absorption Prediction Products Page

  • A global map of the highest HF frequencies affected by a 1 dB attenuation, estimated recovery time - PNG graphics file
  • 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

New — Ionosphere Technology Demonstration of

New — In collaboration with members of the Space Weather Prediction Center (SWPC), the Ionospheric Physics Group of NGDC is pleased to announce a prototype of the Forecasting Ionospheric Real-time Scintillation (FIRST) Tool. By monitoring the height rise of the ionospheric F layer near dusk, an evening equatorial scintillation forecast is possible. Presentations will be made at these upcoming workshops: Space Weather Week (Boulder), International Reference Ionoshere (Colorado Springs).

New — Over the past 2 years, we have modernized access to ionograms on film by digitizing 1 TB from 35 mm film stored in World Data Center "A"'s warehouse.

Locations with Ionosphere Data Archives

  • WDCB in Moscow, WDC1 in England, WDC2 in Japan, & IPS in Australia.
  • International Union Of Radio Science (URSI )
  • Real-Time Ionospheric foF2 data from SWPC in Boulder - Last Two Days ---- Last Month
  • University of Massachusetts Lowell Center for Atmospheric Research (UMLCAR) Didbase

What's new in the Ionosphere?

Interesting Ionosphere Links


[1] Kelley, M. C., The Earth's Ionosphere, Academic Press, Inc:San Diego, 1989.
[2] Davies, Kenneth, Ionospheric Radio, Peter Peregrinus Ltd.:London, 1990.