Analysis of atmospheric circulation condition during severe thunderstorms in Yakutia in 2009-2016

Abstract

The days with large number of lightning discharges in Yakutia and its central part were associated with atmospheric circulation types classified by method of B.L. Dzerdzeevskii. The daily lightning number was obtained by three lightning location systems detecting radiopulses of very low frequency radiated by lightning discharges. The days with intense thunderstorms were selected by the 0.7 level of maximum lightning number in summer season, and the days of minimum lightning activity were selected by 0.3 level of maximum. The elementary circulation mechanisms (ECM) were revealed for severe thunderstorms in Yakutia: ECM 8a, 8dw, 9a, 12a of north meridional circulation group, ECM 13s of south meridional circulation, ECM 2b of zonal circulation and ECM 3 of the disturbace of zonal circulation. Generally, the intense thunderstorms were associated with cyclones of southern outlets of Far East summer monsoon and outlets moving from southwestern.