Variability in the terrestrial ionosphere causes challenges for radio astronomy at low frequencies, including those at which LOFAR operates.
The Dynamic Ionospheric Notifications for Operations and Scheduling (DINOS) project seeks to use ionospheric information to inform the scheduling of radio astronomy observations. This is designed to both identify times it is favorable to observe and, when observations have taken place, to determine if the computational expense required to process the observations is difficult to justify based on the ionospheric conditions.
This content summarizes the work undertaken during the first year of this project (September 2024 – August 2025).
The principle outcomes are:
- A model has been developed to predict ionoscore, a measure of the ionospheric variability relevant to radio astronomy based upon ionospheric conditions. This model has been evaluated. At present, this model is only valid for daytime conditions. While this model has significant potential, it is not yet practical to use this for dynamic scheduling. If a threshold can be determined for ionoscore (above which the ionosphere is judged to be ‘too variable’ for radio astronomy), then the ability of this model to predict whether conditions are suitable for radio astronomy can be assessed. This final step will result in a usable model.
- A climatology of ionospheric structures observed by LOFAR has been developed. This shows that ionospheric structures are more likely to occur in summer (particularly June and July) and in the evening between 20 UT and 01 UT (approximately 21 LT – 02 LT).
- A link has been shown between thunderstorm activity and ionospheric structures which can be observed with LOFAR, with a lag of ~2 hours (ionospheric structures follow thunderstorms).
- An extreme space weather event can be followed by conditions which are extremely favorable for radio astronomy. It could be advantageous to observe approximately 18-36 hours after an extreme event.