HF Systems
FORECAST SOL: Normal green MAG: Disturbed red ION: Moderate yellow Looking for something? Site search go to search page
HomeHF SystemsGlobal HFPolar Cap Absorption Thursday, Jun 30 2016 17:42 UT
Global HF

Polar Cap Absorption

A polar cap absorption event results from the ionisation of the D-layer of the polar ionosphere by high energy protons. A PCA causes a HF radio blackout for trans polar circuits and can last several days. PCAs are almost always preceded by a major solar flare with the time between the flare event and the onset of the PCA ranging from few minutes to several hours.

See Real Time Riometer Data from Antarctic Stations.

The icon below indicates the estimated absorption in db of a 30 MHz riometer from Casey station in Antarctica. These figures give an indication of the severity of the PCA. The background colour of the icon is red when absorption exceeds 1db and green otherwise.

Details of any current proton event are given below:

(last updated 30 Jun 2016 17:40 UT)

10MeV Proton/PCA Event Began 18 06 2015 1105UT and is in progress 10MeV Proton/PCA Event Ended 19 06 2015 0155UT 10MeV Proton/PCA Event Began 21 06 2015 2020UT and is in progress 10MeV Proton/PCA Event Ended 24 06 2015 0510UT 10MeV Proton/PCA Event Began 26 06 2015 0130UT and is in progress 10MeV Proton/PCA Event Ended 26 06 2015 0240UT 10MeV Proton/PCA Event Began 26 06 2015 0425UT and is in progress 10MeV Proton/PCA Event Ended 27 06 2015 0525UT 10MeV Proton/PCA Event Began 27 06 2015 0650UT and is in progress 10MeV Proton/PCA Event Ended 27 06 2015 0715UT 10MeV Proton/PCA Event Began 29 10 2015 0540UT and is in progress 10MeV Proton/PCA Event Ended 29 10 2015 1445UT 10MeV Proton/PCA Event Began 29 10 2015 1530UT and is in progress 10MeV Proton/PCA Event Ended 29 10 2015 1610UT 10MeV Proton/PCA Event Began 02 01 2016 0415UT and is in progress 10MeV Proton/PCA Event Ended 02 01 2016 0745UT

/Images/HF%20Systems/Global%20HF/Polar%20Cap%20Absorption/ico_PolarCapAbsorption.gif

(last updated 30 Jun 2016 17:40 UT)

No proton event in progress

Note: Proton event descriptive text will lag realtime due to data smoothing.

Current proton fluxes are as follows:

(last updated 30 Jun 2016 17:40 UT)

GOES Gp satellite Energetic Proton Flux (Courtesy of SWPC, Boulder Colorado, USA) Units: Protons/cm2-s-sr 10MeV and 100MeV threshold proton flux level is 10 proton flux units (PFU) Date: 30 06 2016 1730 UT 1MeV Proton flux: 1.75e+01 5MeV Proton flux: 2.43e-01 10MeV Proton flux: 2.13e-01 100MeV Proton flux: 3.72e-02

GOES satellite proton flux data for this page are provided by US Space Weather Prediction Center in Boulder.

go to top of page