The relationship between stratospheric polar vortex distortions and tropospheric cold air surges

It has been documented in studies using reanalysis datasets that distortions (splits or displacements) of the stratospheric polar vortex in the wintertime Northern Hemisphere are often followed by cold-air outbreaks in the midlatitude troposphere. However, the reverse is also true, namely cold-air outbreaks in the midlatitude troposphere often precede analyzed stratospheric polar vortex distortions. Events and processes during February 2014 are being studied in order to better understand this relationship. A near split of the 10-mb polar vortex at this time coincided with repeated cold-air outbreaks in the lower troposphere over North America. Tropospheric column (1000 - 200 mb) cooling preceded and was collocated with 10-mb geopotential height falls associated with the near-splitting of the 10-mb polar vortex. The dynamical coupling between the antecedent tropospheric cooling and the collocated stratospheric geopotential height falls is being investigated and will reported. Emerging from this study will hopefully be a more complete picture of stratospheric polar vortex distortions, namely that they are caused not only by high latitude, stratospheric warming as has been previously documented, but also by lower latitude tropospheric cooling.