Rayleigh/Raman lidar observations of gravity wave activity from 15 to 70 km altitude over Syowa (69°S, 40°E), the Antarctic

Abstract

The potential energy of gravity waves (GWs) per unit mass (Ep), at altitudes of 15–70 km, has been examined from temperature profiles obtained by a Rayleigh/Raman lidar at Syowa Station (69°S, 40°E) from May 2011 to October 2013, with the exception of the summer months. The GWs with ground‐based wave periods longer than 2 h and vertical wavelengths between 1.8 and 16 km were extracted from the temperature profiles. Ep was larger in winter than in spring and fall, although in 2012, at altitudes below 30 km, Ep was larger in spring than in winter and fall. Ep increased with a mean scale height of 11.3 km. Ep profiles showed a local maximum at an altitude of 20 km and a minimum at 25 km in almost every month, which has not been reported by previous studies observed by radiosondes. The values of Ep in October of 2012 were smaller at 35–60 km and larger at 20–35 km than those in October of 2011 and 2013. This difference in the Ep profile is most probably caused by different seasonal variations of zonal winds. The larger and smaller Ep values seem to be observed both below and above the altitude at which the zonal wind speed reached 0 m s−1. This result suggests that wind filtering of gravity waves with small phase speeds is significantly important in early spring.

Effects of Horizontal Wind Structure on a Gravity Wave Event in the Middle Atmosphere Over Syowa (69°S, 40°E), the Antarctic

“…These results are consistent with the results from previous studies in the Antarctic region (Kaifler et al, 2015;Kogure et al, 2017;Liu et al, 2014;Zhao et al, 2017). This value increased by 2-3 times at each 10 km of altitude increase between 40 and 60 km altitudes, and the winter (June to August) mean values at each altitude were 2-3 times larger than those of the fall (March to April) and spring (October) periods.…”

“…The temperature profiles in an altitude of typically 10-80 km were derived from the photon counts acquired by the RR lidar, as was performed by Kogure et al (2017). The effective vertical and temporal resolutions were 900 m and 1 hr, respectively.…”

“…In addition, parameterizations in most of practical GCMs take into account only vertical propagation of these waves neglecting horizontal propagation, which provides inaccurate magnitude, direction, and distribution of GW drag (Kalisch et al, 2014). Kogure et al (2017) demonstrated seasonal and vertical variations of GW activity over Syowa Station in the Antarctic (69°S, 40°E), using a Rayleigh/Raman (RR) lidar during the period 2011 to 2013. The GWs with westward wavenumbers are refracted toward the PNJ due to the meridional zonal wind shear and converge to this region.…”

An Introduction to Atmospheric Gravity Wave Science in the Polar Regions and First Results From ANGWIN

“…This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. wave field from the stratosphere to the lower mesosphere and demonstrates the role of wind filtering in determining the gravity wave field at a given height (Kogure et al, 2017).…”

“…A climatological paper studying waves in the lower stratosphere above Halley (75°S, 26°W), Antarctica is also included in the collection, examining the variation in gravity wave properties throughout the year (Moffat‐Griffin & Colwell, ). The final paper in the collection uses LIDAR observation from Syowa (69°S, 40°E), to study the gravity wave field from the stratosphere to the lower mesosphere and demonstrates the role of wind filtering in determining the gravity wave field at a given height (Kogure et al, ).…”