Solar activity impact on the Earth’s upper atmosphere

Abstract

The paper describes results of the studies devoted to the solar activity impact on the Earth's upper atmosphere and ionosphere, conducted within the frame of COST ES0803 Action. Aim: The aim of the paper is to represent results coming from different research groups in a unified form, aligning their specific topics into the general context of the subject. Methods: The methods used in the paper are based on data-driven analysis. Specific databases are used for spectrum analysis, empirical modeling, electron density profile reconstruction, and forecasting techniques. Results: Results are grouped in three sections: Medium-and long-term ionospheric response to the changes in solar and geomagnetic activity, storm-time ionospheric response to the solar and geomagnetic forcing, and modeling and forecasting techniques. Section 1 contains five subsections with results on 27-day response of low-latitude ionosphere to solar extreme-ultraviolet (EUV) radiation, response to the recurrent geomagnetic storms, long-term trends in the upper atmosphere, latitudinal dependence of total electron content on EUV changes, and statistical analysis of ionospheric behavior during prolonged period of solar activity. Section 2 contains a study of ionospheric variations induced by recurrent CIR-driven storm, a case-study of polar cap absorption due to an intense CME, and a statistical study of geographic distribution of so-called E-layer dominated ionosphere. Section 3 comprises empirical models for describing and forecasting TEC, the F-layer critical frequency foF2, and the height of maximum plasma density. A study evaluates the usefulness of effective sunspot number in specifying the ionosphere state. An original method is presented, which retrieves the basic thermospheric parameters from ionospheric sounding data.

Ionospheric anomalies detected by ionosonde and possibly related to crustal earthquakes in Greece

“…by solar EUV, magnetospheric and dynamo electric fields, changing thermospheric circulation and neutral composition, TADs etc. ; Bremer et al, 2009;Kutiev et al, 2013;Mikhailov and Perrone, 2015) and from below (e.g. planetary and gravity waves, neutral gas vertical motion and eddy diffusion changing thermospheric neutral composition, tropospheric electric fields not necessary related to seismic processes).…”

What characterizes planetary space weather?

“…The main heating sources of the terrestrial planetary upper atmospheres are the absorption of the solar UV flux and the consequent impact of the solar wind Wedlund et al 2011;Kutiev et al 2013). This energy is transported by heat conduction to lower layers of the thermosphere where energy can be radiated locally by infrared active molecules such as CO 2 (González-Galindo et al 2009) contributing to the cooling of the atmosphere.…”

Progress in space weather modeling in an operational environment

“…A new ionospheric forecasting algorithm suitable for operational applications, the Solar Wind driven autoregression model for Ionospheric short-term Forecast (SWIF), was recently introduced Kutiev et al 2013). SWIF combines historical and real-time foF2 observations with IMF parameters obtained in real time at the L1 point from NASA/ ACE spacecraft.…”