Forecast of Ionospheric Irregularities and Scintillation: Challenges and Research

Abstract:

Forecast of ionospheric scintillation eventually falls into forecast of ionospheric irregularities (FII). The reason is that scintillation effects vary significantly with signal carrier frequency, and are largely determined by the scale size of irregularities intercepted by the radio waves. From decades of research we have learnt that triggering and development of ionospheric irregularities are driven by ionospheric plasma instabilities and dynamical processes that are affected by ITM coupling processes. We have also learnt that mechanisms of these processes vary with latitudes. Conceivably FII needs to forecast the responsible ITM processes. However, state-of-the art of forecasting capability for ITM processes is far from satisfaction today.

In research to forecast the FII and responsible ITM processes, models that are based on or assimilating ionospheric measurements, such as GNSS data collected from ground-based GNSS networks and spaceborne GNSS receivers, can play a significant role. Examples of these models include Global Map of Ionospheric Irregularities (GMII), Global Assimilative Ionospheric Model (GAIM), and Global Ionospheric Map. These techniques provide global snapshots of ionospheric irregularities and 3D or 2D ambient ionospheric state every 5 to 15 minutes respectively. The scale size of such irregularities and ambient state ranges from hundred meters to a few tens kilometers for irregularities and larger than 300 kilometers for the ambient state.

In this presentation, use of GMII, GAIM, and GIM to derive useful information from small- and large-scale ionopsheric variations will be demonstrated with observed events. How the information benefits FII will also be addressed.