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In this study we present possibility of continuous measurements of lightning-associated transient luminous events (sprites, elves and blue jets) from the ISS altitude using the EUSO telescope. From global lightning data we estimated possible detection rates of lightning and TLEs. We also estimated photon numbers and optical spectra of TLEs in the near-ultraviolet region (300 – 400 nm) where the fluorescence emission caused by CRs exists. These results imply that EUSO has enough capabilities to monitor not only super-GZK CRs but also global lightning and TLEs.

The critical-charge criterion of the stem-leader transition and the shielding effects of space charges on the streamer inception are two most contested issues on the inception of positive upward leader–streamer system (LSS). In this paper, a series of simulation experiments on the LSS inception were designed and carried out. A new critical-charge criterion in the range of 0.2–0.3 μC was proposed, and the previous criterion of 1.0 μC was proved to be harsh. The shielding effect of positive space charges on the streamer inception was verified directly by the experiment results. A theoretical formula for calculating the LSS inception voltage by the first-corona inception voltage was obtained. An appropriate first-corona inception time for getting an earlier LSS inception was proved to be existent. At last, the effects of the so-called improved lightning rods, such as the early streamer emission rod (ESE) and the controllable lightning rod (CL), were discussed, and it seemed that they would not help to extend the protective zones of the lightning rods.

Lightning data, measured from April to October 2002 in an area of northern Italy, have been analyzed by using the Allan Factor statistics. The sequence of lightning time-occurrences is characterized by two scaling regions, which reveal intra-cluster (inside an individual thunderstorm) and inter-cluster (among successive thunderstorms) time-clustering properties of lightning data. We investigated intra- and inter-cluster correlations for three classes of lightning: (i) the whole series, (ii) the sequence of only negative flashes and (iii) that of only positive flashes. Furthermore, we performed the analysis of the scaling behavior of the three classes of lightning varying the current intensity threshold.

Two years of lightning data, measured during 2002 and 2003 in an area of southern Italy, have been analyzed in order to reveal scaling behaviour in their time dynamics. We used the Allan Factor method to evidence the presence of time-clustering in the lightning data. We found that i) the sequence of lightning time-occurrences is characterized by two scaling regions, which reveal intra-cluster (inside an individual thunderstorm) and inter-cluster (among successive thunderstorms) time-clustering properties of lightning data. A crossover timescale is identified, which is connected with the mean duration of a thunderstorm. We investigated intra- and inter-cluster time-dynamics for the whole sequence as well as the sequence of only positive and only negative flashes. The negative lightning show a time-clustering feature stronger than that of the positive lightning.

Lightning density variation was analyzed in the area with borders of 56–72 N, 105–150 E, which was divided into 12 parts of 4 × 15 degrees in latitude and longitude. The spatial distribution of lightning density was obtained from the data (2009–2020) of World wide lightning location network (WWLLN), and lightning pulse number estimates were done by the data of two single-point lightning detectors: Stormtracker (Boltek Corporation) (effective radius of 480 km, 2009–2020) and a lightning direction finder (effective radius of 1200 km, 1999–2016). The lightning density showed some relation to orography and a linear decline with increasing latitude. Intense thunderstorms in the southern and central parts of Yakutia (up to 68 N) were often formed under the influence of cyclonic activity in the southwestern and southern regions of Yakutia. In the years with a peak lightning number in the north of Yakutia, lightning activity in southern parts was relatively low until 2018. Annual lightning variation in the eastern parts was not related to annual variation in the central parts of Yakutia because of the obstacles of the Verkhoyansk ridge. The sharply continental climate of Yakutia in the summer season is characterized by meridional outlets of southern cyclones from Transbaikalia, occurring during the disturbance of the zonal transport dominant in the winter season in Yakutia. Southern outlets produce intense summer thunderstorms, that resulted a significant contribution to the total lightning number per season. In the rear of the southern cyclones, the Arctic air inflows caused periods of significantly reduced lightning activity before or after peaks in the seasonal variation of lightning number.

Changes in solar activity lead to adverse conditions within the upper atmosphere which may cause disruption of satellite operations, communications, navigation, and electric power grid. The term space weather is used to refer to changes in the Earth's space environment. This paper reviews plasma waves, found in all parts of the ionosphere and magnetosphere, in the context of space weather. Generated by energetic particles within the magnetosphere, these waves in turn cause particle accelerations, heating, and precipitation, taking an active part in determining space weather. Terrestrial lightning is an important source of plasma waves and forms a link between the lower and the upper atmosphere. Though many aspects of plasma waves such as their morphology and association with energetic particles and geomagnetic phenomena are well established, their generation mechanisms in most cases remain elusive. Current research involving active and passive, ground and space borne experiments, modeling, and simulation is providing better understanding of plasma wave generation mechanisms and the relation of plasma waves to other space weather parameters such as variations in geomagnetic field and energetic particle fluxes resulting from solar storms. Potentially, plasma waves could serve as one of the key indicators of space weather.

The changing cosmic ray rate has been proposed as a mechanism which could have contributed significantly to the global warming seen during the last century. The evidence for this is discussed and upper limits for the effect are derived from the evidence. The effects of cosmic rays on lightning and its effect on the global electric circuit will also be discussed.