Potential sources of inertia-gravity waves (IGWs) in the lower stratosphere (z = 15–22 km) at Jang Bogo Station, Antarctica (74°37′S, 164°13′E) are investigated using 3-year (December 2014 to November 2017) radiosonde data, including the 25-month result (December 2014 to December 2016) analyzed in Yoo et al. (2018, https://doi.org/10.1029/2018JD029164, Part 1). For this investigation, three-dimensional backward ray tracing calculations are conducted using the Gravity wave Regional Or Global RAy Tracer. Among 248 IGWs, 112, 68, and 68 waves are generated in the troposphere (z < 8 km), tropopause (z = 8–15 km), and lower stratosphere (z = 15–18.5 km), respectively. These waves mainly propagate from the northwestern and southwestern regions of Jang Bogo Station dominated by the prevailing westerlies between the upper troposphere and lower stratosphere. Potential sources of IGWs are categorized into orography, fronts, convection, and the flow imbalance including the upper-tropospheric jet stream. In the troposphere, relatively large numbers of waves are associated with fronts (37) and orography (35) compared with convection (28). In the tropopause (stratosphere), 36 (42) waves, including 11 cases associated with the upper-tropospheric jet stream, are excited by the flow imbalance. Waves related to the flow imbalance are characterized by low intrinsic frequency (1–2f), short vertical wavelength (1–2 km), and longer horizontal wavelength (50–1000 km), whereas the waves induced by the tropospheric sources have wider ranges of intrinsic frequency (1–20f) and vertical wavelengths (1–15 km) with relatively shorter horizontal wavelengths (less than 500 km).
Bibliographical noteFunding Information:
This work was supported by Research Funds PE19020 and PE20100 from the Korea Polar Research Institute. The first author is supported by the Global PhD Fellowship Program (2019H1A2A1077307). The authors sincerely appreciate the support of the Korea Polar Research Institute for the radiosonde data. The Jang Bogo Station radiosonde data used for this research are stored in Korea Polar Data Center (KPDC) and available upon request (https://kpdc.kopri.re.kr/). The authors also thank to the access to the reanalysis data sets ERA-Interim (http://apps.ecmwf.int/datasets/) and ERA5 (https://cds.climate.copernicus.eu/). Further thanks for the provision of ETOPO1 data (https://www.ngdc.noaa.gov/mgg/global/) and GPM-IMERG data (https://pmm.nasa.gov/gpm).
All Science Journal Classification (ASJC) codes
- Atmospheric Science
- Earth and Planetary Sciences (miscellaneous)
- Space and Planetary Science