The New Daily Ionospheric Forecast Service (DIFs)

For nearly 30 years the Advanced Technology Centre - Gt Baddow has produced and issued a daily ionospheric forecast. A recently enhanced service has been implemented under co-funding through the ESA Space Weather Applications Pilot Project and is part of the Space Weather European Network (SWENET).

The service now offers three HF Forecasts,
two 24 hourly forecasts for
high latitudes (polar and auroral regions)
low latitudes (equatorial region)
and a 12 hourly forecast for
mid latitudes.
These are aimed at HF sky-wave users who suffer from degraded performance during solar & geomagnetic storms and wish to have advance warning of poor propagation conditions.

A SATCOM disturbance warning service has been introduced to provide SATCOM users with an advance forecast of conditions on Earth to space communications links for latitudinal regions and timezones.

During the severest events (e.g. Oct 28th 2003) HF sky-wave circuits can disappear completely. Many commercial airlines use HF on transatlantic services to provide position reports to air traffic control. On the 28/29th Oct, HF circuits were unworkable leading to air traffic control restricting flights to mid-latitudes (rather than the usual polar routes) and increasing the spacing between aircraft. This lead to delays to all flights across the Atlantic. The SATCOM disturbance warning forecast provided to SATCOM operators has been developed to give users an indication of scintillation activity. Under moderate and severe scintillation SATCOMs equipment can suffer loss of lock & synchronisation. GPS users will also suffer degradation in location accuracy and even lose position completely through the inability of the RF receivers to lock onto the signals.

We can now provide our HF users with a 6 hourly up-dated forecast, 7 days a week, 365 days a year service and is available via email and web access. SATCOM operators receive a daily forecast of scintillation (fading) as a function of local time for different latitude bands.

The HF forecast Daily Ionospheric forecast has two sections.

1) A summary of the solar, geophysical and ionospheric environment and HF propagation conditions for the previous 24 hour period.

2) A forecast of the HF propagation conditions together with predicted indices.

The DIF provides an ionospheric correction factor (ICF) which links directly into WinHF - our proprietary HF propagation prediction programme.

The new SATCOM forecast provides users with a forecast of the expected scintillation quantified at three levels of fade depth.

For details of acronyms, definitions and forecast descriptions please click here.

For more details on receiving the Daily Ionospheric Forecast, the SATCOM forecast or the HF propagation prediction program (WINHF) please contact:
Nigel Wheadon (Tel: +44 (0)1245 242143)
Site Owner: nigel.wheadon@baesystems.com