Lightning activity in northern Europe during a stormy winter: disruptions of weather patterns originating in global climate phenomena

Abstract

Abstract. In this study, we use World Wide Lightning Location Network data and investigate properties of more than 90 000 lightning strokes which hit northern Europe during an unusually stormy winter in 2014/15. Thunderstorm days with at least two strokes hitting an area of 0.5∘ × 0.5∘ occurred 5–13 times per month in the stormiest regions. Such frequency of thunderstorm days is about 5 times higher than the mean annual number calculated for the same region over winter months in 2008–2017. The number of individual winter lightning strokes was about 4 times larger than the long-term median calculated over the last decade. In the colder months of December, January and February, the mean energy of detected strokes was 2 orders of magnitude larger than the global mean stroke energy of 1 kJ. We show for the first time that winter superbolts with radiated electromagnetic energies above 1 MJ appeared at night and in the morning hours, while the diurnal distribution of all detected lightning was nearly uniform. We also show that the superbolts were often single stroke flashes and that their subsequent strokes never reached megajoule energies. The lightning strokes were concentrated above the ocean close to the western coastal areas. All these lightning characteristics presume anomalously efficient winter thundercloud charging in the eastern North Atlantic, especially at the sea–land boundary. We found that the resulting unusual production of lightning could not be explained solely by an anomalously warm sea surface caused by a positive phase of the North Atlantic Oscillation and by a starting super El Niño event. Increased updraft strengths, which are believed to accompany the cold-to-warm transition phase of El Niño, might have acted as another charging driver. We speculate that a combination of both these large-scale climatic events might have been needed to produce the observed enormous amount of winter lightning in winter 2014/15.

Spaceborne Observations of Lightning NO2 in the Arctic

“…The constant ratio is calculated using two factors: the number of strokes per flash (flash multiplicity) and the mean ratio of IC to CG flashes (also known as the Z ratio) in the high latitudes. The flash multiplicity is highly sensitive to both the detection efficiency and the algorithm used to group strokes into flashes. − The mean multiplicity value for high-latitude studies is estimated to be 1.2 . In addition, the mean Z ratio of high-latitude flashes is between 1 and 1.3. − To evaluate the sensitivity of the constant ratio, we have used different values (1:2 and 2:1) in Table S4 to assess the uncertainty of estimated LNO x emissions.…”

The correlation between lightning and various weather parameters in the Padang monsoon system

“…On the other hand, the correlation between lightning and rainfall was weak during the dry season, as shown in Figure 6(b). Various studies have shown that the factors that influence lightning-rainfall are: type of thunderstorm, geographic region, local climatology, and convection regime [5], [10], [11], [15]. In general, the lightning-rainfall characteristics in Padang follow the pattern of region B, where region B has two rainfall peaks, namely March-April-May (MAM) and October-November (ON).…”

Time Series Models for Radiated Electromagnetic Energy of Lightning Strokes Detected by World Wide Lightning Location Network

“…Using optical strokes data detected by Vela satellite in [5], the author identifies the strokes optical energy that is 100 times more powerful than usual lightning and discovered 20 strokes in the super-bolts category. In [6], the authors depict lightning activity across northern Europe during a severe winter in 2008-2017. During the colder months (Dec, Jan and Feb), the mean energy of recorded strokes was two orders of magnitude bigger than the global mean stroke energy of 1 kJ.…”