Observations and numerical modelling of mountain waves over the Southern Alps of New Zealand

Abstract

A detailed case study of mountain waves observed over the South Island of New Zealand during the Southern Alps Experiment is presented. The purpose of the study is to document the waves generated over this region, to explore the extent to which high-resolution radiosonde data can be used to determine gravity-wave parameters, and to estimate the vertical flux of horizontal momentum produced by flow over the Southern Alps. Organized wave clouds were observed in a visible satellite image on 20 October 1996 and are thought to have been produced by partially trapped lee waves. Using background flow fields derived from a radiosonde sounding, the theoretical horizontal wavelength of the partially t..