Temperature and dynamical regimes of the northern hemisphere extratropical atmosphere during sudden stratospheric warming in winter 2012–2013

Abstract

The major sudden stratospheric warming (SSW) in the beginning of January 2013 led to consid erable temperature growth in the polar stratosphere (up to 60 K at ~44 km altitude), to mean zonal wind reversal, to the split of the stratospheric polar vortex, and to a change in the temperature and dynamic regimes of the mesosphere and lower thermosphere. Using the data of reanalysis and ground based spectrometric and satellite observations, the changes in thermodynamic parameters related to the SSW and expanding from the troposphere to the lower thermosphere are analyzed. An intensification of wave activity fluxes from the tro posphere to the stratosphere is revealed a week before the SSW over East Siberia and China. It is shown that wave trains propagating eastwards in the upper troposphere could contribute to the intensification of an anti cyclone over the northeast Atlantic Ocean a week before the SSW. In its order, such intensification has led to the split of the stratospheric polar vortex into two parts during the SSW.

Identifying Perturbations That Tipped the Stratosphere Into a Sudden Warming During January 2013

“…The deepening extra‐tropical cyclone and North Atlantic blocking correspond well with previous analyses of this event, as well as tropospheric precursor locations for SSWs (Coy & Pawson, 2015; Garfinkel et al., 2010; Kolstad et al., 2010; Lee et al., 2019; Martius et al., 2009; Tripathi et al., 2016; Vargin & Medvedeva, 2015). However, these studies do not demonstrate causality, that is, if changing these features impacts the prediction of the SSW, which is our aim.…”

“…A Rossby wave propagating over North America enters the Atlantic basin and encounters the weakened flow around the 3 January 2013 (Vargin & Medvedeva, 2015). A ridge develops across the Atlantic sector (Figure 1f, gray contours) which is significantly stronger in “correct” members (Figure 1f, shading) and projects positively onto the tropospheric planetary wave‐1 forcing (Figure 1b).…”

“…This event was associated with cold air outbreaks across Europe and North Asia during January 2013 (Liu & Zhang, 2014; Nath et al., 2016). Studies suggest that tropospheric precursors, including blocking and an explosively developing extratropical cyclone, and pre‐conditioning of the stratosphere, played a role in its development (Attard et al., 2016; Coy & Pawson, 2015; Vargin & Medvedeva, 2015). A multi‐model comparison indicates the SSW was predictable up to 2 weeks ahead, with the development of planetary wave activity in the troposphere being a key component (Tripathi et al., 2016).…”