Effects of vertically propagating mountain waves during a strong wind event over the Ross Ice Shelf, Antarctica

Weather forecasting in the Antarctic presents many
challenges, with strong wind events (SWEs) often
disrupting air and field operations. Here, we study the
mechanisms responsible for a SWE (maximum wind
speed 22 ms–1) that occurred at the McMurdo/Scott
Base region on the Ross Ice Shelf (Antarctica) over
12–13 October 2003. The study is based on in situ
observations, satellite imagery and output from the
Antarctic mesoscale prediction system (AMPS) model.
The event occurred during the passage of a complex
low pressure system that increased the pressure
gradient between the northwest Ross Ice Shelf and the
continental high, initiating a strong southerly flow.
AMPS simulations as well as upper air sounding profiles
from McMurdo station showed the involvement
of large amplitude vertically propagating mountain
waves over the area. The amplification of mountain
waves by the self-induced critical level reflected all the
energy back towards the surface to generate high
downslope winds.