The D-Region Absorption Prediction (D-RAP) Model, produced by the Space Weather Prediction Center (SWPC), provides real-time graphic and text information about global High Frequency (HF) radio propagation conditions related to the ionosphere's D-region. D-RAP provides a suite of graphic and text information about global High Frequency (HF) radio propagation conditions related to the ionosphere's D-region.
Help
For more information on D-RAP or to comment on the D-RAP product, visit SWPC Real-Time D-RAP2.
Product Details
The D-Region of the ionosphere is important to the propagation of HF radio signals. The lowest available frequency for HF users is directly related to the electron 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.
Inputs
The D-RAP model uses GOES X-ray flux, GOES proton flux, estimated planetary geomagnetic activity index (Kp), and monthly L-values derived from the IGRF main field geomagnetic model as inputs.
Outputs
- A global map of the highest HF frequencies affected by a 1dB attenuation, estimated recovery time
- A north pole map of the highest frequencies affected by a 10dB attenuation, estimated recovery time
- A south pole map of the highest frequencies affected by a 10dB attenuation, estimated recovery time
- ASCII tabular values of total absorption at 10MHz - text file
The D-Region Absorption Prediction Product - Release 2, became an official NWS product on November 18, 2009
