For automated searches for sudden stratospheric warming (SSW) events, their beginning/ending dates are defined as extremes of the first-order time derivative simultaneous with zero values of the second-order time derivative of temperature and zonal wind. The dates of the fastest changes in temperature and zonal wind differ not more than two days for SSW searching the JRA-55 database. The SSW dates correspond, within the limits of the uncertainties, to those obtained with other standard methods. Frequently, before SSW developments, increases in the heat fluxes directed to the North Pole occur, which can heat the polar stratosphere.
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