Evaluating Common Characteristics of Antarctic Tropopause Polar Vortices

Abstract

Tropopause Polar Vortices (TPVs) are coherent circulations that occur over polar regions and can be identified by a local minimum in potential temperature and local maximum in potential vorticity. Numerous studies have focused on TPVs in the Arctic region, however, no previous studies have focused on the Antarctic. Given the role of TPVs in the Northern Hemisphere with surface cyclones and other extreme weather, and the role that surface cyclones can play on moisture transport and sea ice breakup, it is important to understand whether similar associations exist in the Southern Hemisphere. Here, characteristics of TPVs in the Antarctic are evaluated for the first time under the hypothesis that their characteristics do not significantly differ from those of the Northern Hemisphere. To improve understanding of Antarctic TPV characteristics, this study examines TPVs of the Southern Hemisphere and compares them to their Northern Hemisphere counterparts from 1979-2018 using ERA-Interim data. Common characteristics of TPVs including frequency, locations, lifetimes, strength, and seasonality are evaluated. Results indicate that topography correlates to the geographic distribution of TPVs and the locations of local maxima TPV occurrence, as observed in the Northern Hemisphere. Additionally, TPVs in the Southern Hemisphere exhibit seasonal variations for amplitude, lifetime, and minimum potential temperature. Southern Hemisphere TPVs share many similar characteristics to those observed in the Northern Hemisphere, including longer summer lifetimes.The association of Southern Hemisphere TPVs and surface cyclone frequency is explored, and it appears that TPVs have a precursory role to surface cyclones, as seen in the Northern Hemisphere.

Examining Atmospheric River Life Cycles in East Antarctica

“…Antarctic surface cyclones have been proven to be frequently associated with a TPV (Gordon et al., 2022). Since ARs are often attended by large cyclonic upper‐level PV anomalies, these PV anomalies may reflect the influence of TPVs.…”

“…TPV tracks are generated using the TPVTrack (v1.0) software, described in detail by Szapiro & Cavallo (2018) and described in its application to Southern Hemisphere TPVs in Gordon et al. (2022). We briefly summarize its key aspects here for convenience.…”

“…The TPV tracks used in this study are the same as those used in Gordon et al. (2022) for the Southern Hemisphere.…”

“…The TPV objects are tracked over time using horizontal and vertical correspondences between time steps to create TPV tracks that also consider vortex splits and mergers. The TPV tracks used in this study are the same as those used in Gordon et al (2022) for the Southern Hemisphere.…”

Characteristics and Variability of Precipitation Across Different Sectors of an Extra‐Tropical Cyclone: A Case Study Over the High‐Latitudes of the Southern Ocean

“…These clouds often exist at temperatures colder than that of the Hallett-Mossop process (−8 to −3°C), suggesting that relatively poorly understood secondary ice production processes (Järvinen et al, 2022;Korolev & Leisner, 2020;Sotiropoulou et al, 2020) can be involved in the production of precipitation. Further a variety of dynamical mechanisms are known to exist at these latitudes including polar vortices and meso-vortices, fronts, and atmospheric rivers, but have rarely been studied (Gordon et al, 2023;McCoy et al, 2021;Rauber et al, 2020). Ye et al (2014) noted the importance of developing a better understanding of the physical processes that govern cloud formation and precipitation in order to reduce uncertainty in precipitation estimates over the high latitudes.…”