Global characteristics of the westward-propagating quasi-16-day wave with zonal wavenumber 1 and the connection with the 2012/2013 SSW revealed by ERA-Interim

Abstract We analyze global characteristics of the westward-propagating quasi-16-day wave (Q16DW) with zonal wavenumber 1 (W1) in troposphere and stratosphere using wind, meridional vertical velocity, temperature, geopotential, potential vorticity data from European Centre for Medium-Range Weather Forecasts (ECMWF) Interim Re-Analysis during one year December 2012 to November 2013. The amplitudes W1 Q16DW are larger than troposphere, remarkable found at middle high latitudes Northern Hemisphere (NH). More detailed analyses on temporal variation show that this is significantly enhanced 2012/2013 Stratospheric Sudden Warming (SSW) event, strong most likely provides additional forcing splitting displaced polar vortex. Analysis Eliassen–Palm flux (EP flux) its divergence interaction between quasi-stationary planetary waves SSW event reveals it causes an upward heat exerts a westward acceleration background winds, indicating plays important role eastward stratospheric jet reversal. Moreover, amplified occurrence region barotropic and/or baroclinic instability, suggesting local source growing event.