Tropopause Polar Vortex Predictability and Midlatitude Impacts
Key Points
- Tropopause Polar Vortices (TPVs) are coherent, long lived sub-synoptic scale vortices along the tropopause.
- TPVs are associated with Arctic Cyclones (ACs), which during the summertime can result in rapid sea ice melt.
- TPVs can enter the midlatitudes via Canada and Siberia, resulting in a wide variety of impacts from Cold Air Outbreaks to rapid cyclogenesis and Rossby Wave initiation.
Research Summary
Tropopause Polar Vortices (TPVs) are coherent, long-lived vortices along the tropopause, identified by a minimum in potential temperature and tropopause height and maximum in
potential vorticity. TPVs can be long-lived with maximum duration upwards of a month, and are sub-synoptic scale features with radii often between 150-600 km. TPVs are most
common in the high latitudes where isolation from the midlatitude jet and its associated horizontal shear, and lower moisture content reducing the detrimental impacts of latent
heat release, favor TPV intensification and maintenance. TPVs on occasion can enter the midlatitudes via Canada and Siberia, where their associated cold pool can contribute to
Cold Air Outbreaks (CAOs), they can provide upper-tropospheric forcing for rapid cyclogenesis, and enhance the potential vorticity gradient resulting in amplification of jet
streaks and potential subsequent Rossby Wave initiation.
My ongoing research is focused on improving our understanding of TPVs in the Arctic and midlatitudes. Given sparse observations in the high latitudes, even removing a few observations can have significant detrimental impacts on forecast skill in the Arctic. Work is ongoing on analyzing the impacts of radiosonde observations on TPV forecast skill. Additionally, while it is understood TPVs can contribute to jet streak amplification and Rossby Wave initiation, relatively little is understood on how this process affects the TPV itself, which is another area of ongoing research. It is also known that TPVs can contribute to CAOs, with a notable case being the historic February 2021 CAO in the Southern United States. Work is ongoing on analyzing the impact of TPV intensity on the evolution of this historic CAO.
Project Background
This work is ongoing as part of my Ph.D. research at the University of Oklahoma, under the advisement of Dr. Steven Cavallo.
Conference Presentations
Burg, T. and S. M. Cavallo, 2022: Sensitivity of the February 2021 U.S. Cold-Air Outbreak to Tropopause Polar Vortex Intensity. 27th Conference on Numerical Weather Prediction, Houston, TX.Burg, T. and S. M. Cavallo, 2021: Analysis of the 19 June 2020 Twin Arctic Cyclones and Tropopause Polar Vortices. 16th Conference on Polar Meteorology and Oceanography, Virtual conference.