Tropopause polar vortices (TPVs) are coherent, closed tropopause-based vortices that spend at least 60% of their lifetime poleward of 65° latitude. TPVs are identified by a local minima in potential temperature and height, and a local maxima in potential vorticity on the dynamic tropopause. TPVs are most common in the Arctic, where they are often associated with the intensification of Arctic cyclones (ACs), but on occasion exit the Arctic into the midlatitudes where they are often associated with cold air outbreaks (CAOs).

This dissertation investigates TPV linkages to ACs, CAOs, and polar lows (PLs), focusing on systematic TPV-AC linkages and case studies of TPV intensity linkages to an AC case, a PL case, and a major CAO. Rapidly deepening ACs are commonly associated with an upstream TPV which becomes vertically aligned with the AC by the end of the rapid deepening episode. Summer cases are associated with closer proximity to the closest TPV and less lower-tropospheric baroclinic instability than winter cases, with summer cases often over the central Arctic Ocean and winter cases often in the North Atlantic into the Barents and Kara seas. Additionally, ACs whose rapid deepening episode coincides with cyclogenesis are less likely to be over the central Arctic Ocean and are farther from the closest TPV relative to ACs that develop at least 24 h prior to the onset of rapid deepening.

Numerical simulations designed to modify the intensity of two TPVs associated with the August 2012 ``Great Arctic Cyclone" show that stronger TPVs are associated with a faster peak deepening rate and earlier peak intensity of the cyclone, but with the closer TPV to the AC exhibiting a greater impact on the intensification rate of the AC, and the farther TPV exhibiting a greater impact on the track of the AC. The increased intensification rate is primarily associated with stronger differential cyclonic vorticity advection downstream of the TPVs. Weakening the broader upper-tropospheric trough within which the closer TPV is embedded in results in a substantially weaker and more progressive AC. Applying the same TPV modification methodology to an intense PL case only results in very minimal impact on the intensity of the PL, and a 10-member initial condition uncertainty ensemble shows the track and intensity of the PL are more sensitive to the amplitude of a ridge upstream of the TPV than the intensity of the TPV.

Finally, an investigation of the role of two merging TPVs in a historic CAO in the southern Great Plains in February 2021 shows both TPVs had a direct role in the evolution of the CAO, but that backward air parcel trajectories from the southern Great Plains were mostly associated with one TPV instead being distributed equally between both TPVs. The control simulation produces the coldest temperatures at the peak of the CAO in the southern Great Plains, as intensifying both TPVs results in an earlier merger and stronger cold pool but a slower and farther north resultant TPV, while weakening both TPVs results in a weaker cold pool. This result differs from past studies of TPV-CAO linkages where a single, fast-moving TPV exhibited a more direct linkage between TPV intensity and CAO magnitude.