Ionospheric research and space weather services

Abstract

This paper concentrates on those major areas where our current physical understanding and recent advances can lead to positive predictions of the expected effects of ionospheric activity on the near-Earth space environment and on technological systems which operate within this environment. It briefly describes some of the key links between solar activity and the various physical processes, which govern ionospheric plasma structure that has been under scientific examination over past several decades but has lately received significant importance in relation to the space weather services. Specific examples during extremely intense solar event show how ionospheric monitoring techniques that have contributed immense data sets and related empirical and theoretical formulations have been incorporated in different ionospheric specification and prediction models for real-time operational applications. Finally, the general question of what might be expected as a result of current activities within different European cooperative projects is addressed.

Introduction

The Earth's ionosphere is a highly dynamic plasma medium that continues to command much interest in both purely scientific and applications communities. It exhibits the long-term (ionospheric climatology) and the short-term (ionospheric weather) variability at all latitudes and longitudes. Scientific research has the goal to explore the characteristics, causes, and consequences of ionospheric structures and dynamics during quiet and disturbed conditions and diverse irregularities by focusing on the extremes of space weather. Proper understanding of Earth's ionosphere is of fundamental practical importance because it is an essential part of telecommunication and navigation systems that use the ionosphere to operate or would operate much better in its absence. In Europe, the need for increased reliability of technological systems whose performance depends on the state of the ionosphere has significantly increased in the last few years and it is strongly related to a broader European collaboration within different frameworks (Cander, 2003; Zolesi and Cander, 2004; Belehaki et al., 2006).

Studies of Earth's ionospheric for several decades attempted to investigate large-scale daytime electrodynamics, structure of E- and F-region irregularities in relation to gravity waves, auroral activity, and tropospheric weather systems. Particularly important have been the studies related to the causes and behaviour of significant changes in electron densities during geomagnetic storms which increase and decay over time scales of a few minutes, and their overall influence on the radio propagation environment. More recent observations including space-based in situ and remote and ground-based measurements together with modelling and theoretical results provide new science of both large-scale and small-scale ionospheric processes. Complementing these new observations are advances in data assimilation models and models of the coupled ionosphere–magnetosphere and of the thermosphere–ionosphere circulation. This science is now widely engaged in providing space weather services from several communities including heliospheric, magnetospheric, ionospheric and atmospheric scientists as well as space weather experts to the users of the space environment affecting life and society.

In the following section, the ionospheric weather aspects will be introduced by using a few examples of the ionospheric behaviour during the October 2003 storm. The following brief overview of the existing and ionospheric models in development provide some basic information on the ionospheric research required for space weather services (3 Existing models, 4 Model in development). It aims to emphasize the complex and interdependent nature of investigations that seek a broad international participation and support. Some examples of the space weather services in Europe will be presented in Section 5. Questions of what might be expected as a result of current activities within different European cooperative projects are addressed in Section 6.