Inertia‐Gravity Waves Revealed in Radiosonde Data at Jang Bogo Station, Antarctica (74°37′S, 164°13′E): 2. Potential Sources and Their Relation to Inertia‐Gravity Waves

Abstract

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).

Observations of Inertia Gravity Waves in the Western Pacific and Their Characteristic in the 2015/2016 Quasi‐Biennial Oscillation Disruption

“…The intrinsic frequency is distributed between 2.2 and 5.8 f in the troposphere and 1.8–3.2 f in the stratosphere. It should be noted that when calculating the vertical wave number, the weighted average will lead to a narrow range of vertical wavelengths, which is also consistent with the results using similar method for the calculation of vertical wave number (Wang et al., 2005; Yoo et al., 2020). However, as the vertical wavelengths are limited by the radiosonde data and calculation method, only relatively short vertical wavelengths with narrow width are discussed in this study.…”

A Statistical Investigation of Inertia Gravity Wave Activity Based on MST Radar Observations at Xianghe (116.9°E, 39.8°N), China

“…Based on the observed wind and temperature profiles, the Stokes‐parameter method can analyze polychromatic wave perturbations (Eckermann, 1996; Eckermann & Vincent, 1989), while the hodograph technique can provide in detail the wave parameter estimate of monochromatic inertia‐GWs (IGWs) perturbations and is extensively used to investigate the IGW activity from various observation data. By means of the hodograph technique, the seasonal and latitudinal variations of IGW parameters in the troposphere and low stratosphere (TLS) are widely studied from the radiosonde observations (e.g., Gong & Geller, 2010; Huang et al., 2018; Moffat‐Griffin et al., 2020; Murphy et al., 2014; Tsuda et al., 1994; Vincent & Alexander, 2000; Yamamori & Sato, 2006; Yoo et al., 2020; Zhang & Yi, 2007). In general, the intrinsic frequency of IGWs increases with increasing latitude, while the ratio of intrinsic frequency to inertia frequency and dominant horizontal and vertical wavelengths decrease slightly with increasing latitude (Alexander et al., 2002; Wang et al., 2005; Zhang et al., 2013).…”

Activities of Small‐Scale Gravity Waves in the Upper Mesosphere Observed From Meteor Radar at King Sejong Station, Antarctica (62.22°S, 58.78°W) and Their Potential Sources

“…In addition to tropospheric jets accompanied by frontal systems, the polar night jet in the stratosphere has also been considered to be an important source for GWs. Several observational studies have revealed enhanced GW activities near the stratospheric polar night jet using lidar (Whiteway et al., 1997), radiosonde (Sato & Yoshiki, 2008; Yoo et al., 2020, 2018; Yoshiki et al., 2004; Yoshiki & Sato, 2000), and satellite (Ern et al., 2011; Schroeder et al., 2009; Wu & Zhang, 2004), and strong GW activities have been observed mainly at the edge of the polar vortex (Whiteway et al., 1997; Yoshiki et al., 2004). Given that the edge of the vortex is often located near KSS, the polar night jet in the stratosphere could be an important source of GWs in the upper mesosphere over KSS.…”

“…Generation of GWs from the jet stream can be related to the imbalance of the large-scale flow associated with the tropospheric jet stream. In order to diagnose the imbalance, the residual of the nonlinear balance equation (RNBE) has been employed (Hertzog et al, 2001;Moore & Abeling, 1988;Yoo et al, 2020;Zhang et al, 2000Zhang et al, , 2001. In addition to tropospheric jets accompanied by frontal systems, the polar night jet in the stratosphere has also been considered to be an important source for GWs.…”