D-Region Absorption Prediction Product Archive

The D-Region Absorption Prediction (D-RAP), Release 2 Product , produced by the Space Weather Prediction Center (SWPC), provides a suite of graphic and text information about global High Frequency(HF) radio propagation conditions relating of the ionosphere's D-region. The D-Region of the ionosphere is critically important to the propagation of HF radio signals. The lowest available frequency for HF users is directly related to the electon density in the D-Region. Due to space weather effects, the electron density can vary dramatically over time scales as short as a few minutes. The D-RAP Model uses empirically determined relationships to compute HF absorption and the highest affected HF frequencies directly from space weather input parameters.

The D-RAP2 Product Description Document (PDD), the Space Weather Journal article - Ionospheric Radio Wave Absorption and the D-RAP Technical Documentation provide additional information pertaining to the operational D-RAP product, the Ionospheric D-Region and the impacts of X-ray and Proton flux on HF communication

The D-Region Absorption Prediction Product is provided by SWPC as part of its mandate to provide real-time monitoring and forecasting of solar and geophysical events. NCEI is the National Archive for the D-RAP model outputs.

1. A global map of the highest HF frequencies affected by a 1 dB attenuation, estimated recovery time - PNG graphics file
2. A north pole map of the highest frequencies affected by a 10dB attenuation, estimated recovery time - PNG graphics file
3. A south pole map of the highest frequencies affected by a 10dB attenuation, estimated recovery time - PNG graphics file
4. ASCII tabular values of total absorption at 10 MHz - text file

The D-Region Absorption Prediction Product - Release 2, became an official NWS product on November 18th, 2009. For more information on D-RAP or to comment on the D-RAP product, please visit the SWPC real-time D-RAP2 Web Site.

D-Region Major Event Animations