Project Participants

Nikolay A. Zabotin (PI)
Oleg A. Godin

Motivation

Recently, observations were reported of rather unusual atmospheric wave activity in Antarctica [Chen et al., 2016]. With a lidar instrument operating at McMurdo, Antarctica, Chen et al. [2016] observed persistent, large-amplitude gravity waves with 3–10 h periods and vertical wavelengths between 20 and 30 km from the stratosphere to lower thermosphere. Remarkably, these waves were present during every lidar observation throughout the five-year observation period [Chen et al., 2016]. No similar atmospheric wave activity was ever observed at mid- and low-latitude locations.

We hypothesize that the persistent atmospheric waves in mesosphere and lower thermosphere, which are observed at McMurdo, Antarctica, are related to the ice cover and, specifically, to low-frequency vibration resonances of the Ross Ice Shelf. Our preliminary analysis indicates that the temporal and spatial scales of atmospheric waves, which would be radiated by the lowest-order modes of RIS vibrations, are consistent with the lidar observations of Chen et al. [2016].

Chen, C., X. Chu, J. Zhao, B. R. Roberts, Z. Yu, W. Fong, X. Lu, and J. A. Smith (2016), Lidar observations of persistent gravity waves with periods of 3–10 h in the Antarctic middle and upper atmosphere at McMurdo (77.83°S, 166.67°E), J. Geophys. Res. Space Phys., 121, doi: 10.1002/2015JA022127. link

Results

Simple models have been developed to describe basic physical properties of resonant vibrations of large ice shelves and their coupling to the atmosphere [Godin and Zabotin, 2016]. Radiation of atmospheric waves by fundamental and other low-order resonance vibrations of large ice shelves is found to be qualitatively similar to previously considered radiation of atmospheric waves by infragravity waves in ice-free water [Godin et al., 2015; Zabotin et al., 2016]. The key features of the persistent atmospheric wave activity, which are observed over Antarctica in the vicinity of the Ross Ice Shelf [Chen et al., 2016], including frequency band, vertical wavelength range, and weak variation of the vertical wavelength with height (see Fig. 5), are explained by the models of the resonant Ross Ice Shelf vibrations proposed in [Godin and Zabotin, 2016].

Publications

Godin, O. A., and N. A. Zabotin (2016), Resonance vibrations of the Ross Ice Shelf and observations of persistent atmospheric waves, J. Geophys. Res. Space Physics, 121, 10,157–10,171, doi:10.1002/2016JA023226. link

***The Project is a Work in Progress. Stay tuned!***