No abstract

No abstract

No abstract

Elves are short-lived (<1 ms) transient luminous events (TLEs) which have been detected by low light cameras in the visible wavelength range at altitudes of about ∼90 km just after the onset of cloud-to-ground (CG) lightning discharges (Fukunishi et al., 1996; Inan et al., 1996). An elve has the shape of a narrow expanding ring propagating outwards from its central position above the parent lightning to horizontal distances up to ∼50-350 km (Barrington-Leigh & Inan, 1999; Fukunishi et al., 1996). The optical luminosity of elves originates in the heating of ionospheric electrons and the subsequent excitation and ionization of N 2 molecules in the lower ionosphere by an intense electromagnetic pulse from a strong CG lightning discharge (Inan et al., 1997). Elves can be produced by lightning discharges of both positive and negative polarities (Barrington-Leigh & Inan, 1999). Marshall et al. (2015) reported exceptional observations of elves produced by intracloud (IC) lightning strokes, forming doublets with the reflection of the electromagnetic waves from the ground. Elve doublets could also occur after a class of terrestrial gamma ray flash events as shown theoretically by Liu et al. (2017). This was very recently confirmed experimentally by Neubert et al. (2019) using Atmosphere-Space Interactions Monitor onboard the International Space Station. Tiger elves with a striped luminosity modulated by convectively generated gravity waves (

Two methods for assimilating radar reflectivity into the COSMO numerical weather prediction (NWP) model were compared to precipitation forecasts. The first method assimilated observed radar reflectivity, and the second one assimilated observed and extrapolated radar reflectivity. The assimilation technique was based on the correction of the model's water vapour mixing ratio. The extrapolation was performed by the COTREC method and was 1 hour long. The model's horizontal resolution was 2.8 km.The comparison of methods was based on verification of the observed and forecast hourly precipitation. The comparison was performed for the 1 st , 2 nd and 3 rd hours of each forecast. On the whole, 45 forecasts from nine days of convective precipitation were evaluated for each hour. The evaluation included subjective verification and the following objective skill scores: Fractions Skill Scores, SAL and a measure based on a categorical-probabilistic approach.The results confirmed that assimilation complemented by the extrapolated data improves the accuracy of precipitation forecasts. The improvement was obvious in a majority of the single forecasts studied, and it is confirmed by all evaluation techniques. COSMO forecasts that used the extrapolation showed reasonable competence in forecasting for the first and the second hours.