Daniel Celiński-Mysław
Geographical Studies, Issue 139, 2014, pp. 21-32
https://doi.org/10.4467/20833113PG.14.022.3012The aim of the paper is to review the state of research on the phenomenon of derecho, with particular emphasis on studies conducted in Europe and on the American continent. The paper presents different approaches to the identification criteria of derecho. The structure and conditions for its formation were characterized. Long-term studies on the multi-annual occurrence of derecho on both continents were described. The presented review of literature led to the conclusion that there are still many opportunities to study mesoscale convective systems which cause derecho on the European continent
Daniel Celiński-Mysław
Geographical Studies, Issue 148, 2017, pp. 11-32
https://doi.org/10.4467/20833113PG.17.001.6269The primary goal of the study was to examine the temporal and spatial variability of values of selected atmospheric instability indices over Poland for the period 2005–2014. The research involved six indices most frequently applied in convection forecasting – Convective Available Potential Energy, K-Index, Lifted Index, Severe Weather Threat Index, Showalter Index and Total Totals Index. The data from three Polish upper air sounding stations ( Łeba, Legionowo, Wrocław ), as well as SYNOP codes on present and past weather and reports on severe meteorological phenomena from the European Severe Weather Database were used in this study. It was found that extremely high values of the selected indices were characterised by strong temporal and spatial variability. Moreover, a detailed analysis of the days when no convective events were observed, despite extreme values of instability indices, demonstrated that the occurrence of isothermal or inversion layers were the most common mechanisms inhibiting the development of severe convective phenomena. Convection was also inhibited when the area was free from an influence of atmospheric fronts, convergence zones or low-pressure troughs.