Isolated mountainous island in regions of strong winds can be significant sources of gravity waves. South Georgia (54.5S 37W) in the South Atlantic is probably the most important such island. The South Georgia Wave Experiment (SG-WEX) is a programme of coordinated observational and modelling studies to investigate the amplitudes, fluxes, climatology and intermittency of the waves generated by South Georgia and in the surrounding region. The programme runs from December 2013 to November 2016. The observational side of SG-WEX includes two month-long radiosonde campaigns that were carried out in January and June 2015, the deployment of a VHF meteor radar in February 2016 to measure mesospheric winds and waves over the island and the use of Radio Occultation observations from the COSMIC constellation of satellites to measure gravity waves over the entire Southern Ocean and Drake Passage. These observational studies have ben complemented by high-resolution modelling studies with the Met Office UM to investigate the formation of wakes from the island and the momentum fluxes from gravity waves generated by the island itself. This talk introduces SG-WEX and presents some highlights of the studies to date. A particular focus here is on the COSMIC RO measurements and the two radiosonde campaigns. Analysis of the RO measurements has used a wavelet technique to identify individual waves and revealed the structure and variability of the wave field around the “hot-spot” region over the Drake Passage and out over the Southern Ocean. The radiosonde results show a marked increase in gravity-wave activity in the wintertime in terms of wave energy density and momentum fluxes, as well as a marked difference in the relative proportion of upward and downward propagating waves seen in the two campaigns.

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*email: N.J.Mitchell@bath.ac.uk
*Preference: Oral