Abstract. The present study attempts to visualize the global equatorial current systems and the proton pressure in the near-Earth magnetosphere based on AMPTE/CCE-CHEM measured proton distributions, which were sorted by the AE index ( "quiet": AE < 100 nT, "active": 100 nT < AE < 600 nT). The data were averaged over 2 years (from January 1985 to June 1987) in order to obtain the necessary spatial resolution with statistical significance. The results provide an average image of proton plasma pressure, proton plasma anisotropy, and current systems as a function of geomagnetic activity. In particular, the changes of pressure anisotropy with local time and the noon-midnight pressure asymmetry are studied and correlated to the current systems out of the equatorial plane that generate the closure circuits. Moreover, we identify and spatially locate two different current systems for the quiet period (the ring current and the inner portion of the quiet thne cross-tail current) and three different current structures for the active period (the ring current, the partial ring current, and the region 2 current).

• Two artificial neural network (ANN) models are built to forecast SYM-H index 1 hour ahead using interplanetary magnetic field measurements. • The developed models are based on two conceptually different neural networks: Long Short-Term Memory and Convolutional Neural Network (CNN). • CNN, used here for the first time for geomagnetic indices forecasting, has proved potentialities worth being further explored.

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[1] One of the most interesting aspects of the global magnetospheric response to solar wind changes is the relationship between storms and substorms. Here we present new results on the relationship between these two different classes of magnetospheric phenomena by approaching the problem on the side of information theory. Using the Auroral Electrojet AL and SYM-H indices as representative proxies of magnetic substorms and storms, we investigate the transfer of information by means of transfer entropy analysis (Schreiber, 2000). The obtained results seem, on average, to indicate the presence of a net transfer of information from AL to SYM-H on time scales shorter than 10 h. On the basis of this result, geomagnetic substorms may act as a driver for the occurrence of geomagnetic storms. However, carrying out a more careful analysis which takes into account the global geomagnetic daily activity, we suggest that the direction of information flow between substorms and storms depends on the global activity level. Indeed, if it is true that a sequence of magnetospheric substorms may drive a moderate storm, it is also true that very large storms may dominate and drive the occurrence of magnetospheric substorms.Citation: De Michelis, P., G. Consolini, M. Materassi, and R. Tozzi (2011), An information theory approach to the stormsubstorm relationship,

The Auroral Electrojet (AE) index, introduced to track the global high‐latitude geomagnetic activity, is representative of two different processes (Kamide and Kokubun, 1996): the solar‐wind directly driven convection enhancement, and the impulsive unloading process. Here, we present a new technique, based on the Local Intermittency Measure analysis, to separate these two contributions in the AE index. In detail, we applied this approach to extract the coherent intermittent structures that are linked with the impulsive unloading process.

Geomagnetically induced currents (GICs), occurring as a result of space weather events, represent a hazard for the secure and safe operation of electrical power grids and oil/gas pipelines. The most exposed countries are those at high latitudes where, in the past, the occurrence of intense GICs has seriously damaged part of their power networks. However, very powerful space weather events have resulted in intense GICs also at middle and low latitudes. The GIC index is a proxy of the geoelectric field, and it can be estimated straightforwardly from magnetic observatory data. In this work, the GIC index is computed to investigate the possible impact of space weather events on the Italian territory. We first calculate the GIC index using data from the magnetic observatories of Castello Tesino, Duronia, and Lampedusa, together covering the whole Italian latitudinal extension, and show its behavior during the 2015 St. Patrick's day storm. Then, we consider measurements from the two longest running Italian magnetic observatories, that is, Castello Tesino and L'Aquila, and estimate the GIC index over more than 20 years of observations. A preliminary characterization of the general risk to which the Italian power grid network is exposed is given. Results show that during periods of high magnetic activity, potentially detrimental GICs could flow through the power network, especially at the highest Italian latitudes that are characterized by a low conductivity lithosphere.

Abstract. The present study attempts to analyze the average ring current density and pressure in the magnetospheric equatoria• plane (as a function of geocentric distance and local time) based on the AMPTE/CCE-CHEM proton distributions according to two different AE ranges, corresponding to a low (AE<100 nT) and a moderate (100 nT

ABSTRACT. Talos Dome is an ice dome on the edge of the East Antarctic plateau; because accumulation is higher here than in other domes of East Antarctica, the ice preserves a good geochemical and palaeoclimatic record. A new map of the Talos Dome area locates the dome summit using the global positioning system (GPS) (72˚47' 14''S, 159˚04' 2'' E; 2318.5 m elevation (WGS84)). A surface strain network of nine stakes was measured using GPS. Data indicate that the stake closest to the summit moves south-southeast at a few cm a Airborne radar measurements indicate that the bedrock at the Talos Dome summit is about 400 m in elevation, and that it is covered by about 1900 m of ice. Snow radar and GPS surveys show that internal layering is continuous and horizontal in the summit area (15 km radius). The depth distribution analysis of snow radar layers reveals that accumulation decreases downwind of the dome (north-northeast) and increases upwind (south-southwest).The palaeomorphology of the dome has changed during the past 500 years, probably due to variation in spatial distribution of snow accumulation, driven by wind sublimation. In order to calculate a preliminary age vs depth profile for Talos Dome, a simple onedimensional steady-state model was formulated. This model predicts that the ice 100 m above the bedrock may cover one glacial-interglacial period.