Two southerly changes observed during the New Zealand Southern Alps Experiment (SALPEX)

The aim of the New Zealand Southern ALPs EXperiment (SALPEX) was to study chiefly, but not exclusively, how the Southern Alps promote precipitation on the upwind side of the mountain chain in pre-frontal northwesterly airstreams. The third and most extensive field phase of the experiment ran for three weeks during October 1996, and documented two events in considerable detail. The present paper reports briefly on the structure of the two cold fronts associated with these events. For further details on the field experiment and its aims see Wratt et al. (1996). The Southern Alps form a narrow barrier 800 km long and oriented northeast-southwest. On average, the mountain range is about 2000 m high, with Mt Cook the highest peak (3754 m). (Figure 1 shows the orography of the South Island and the location of Christchurch.) Anticyclones centred to the northeast of the North Island direct a north or northwesterly airAust. Met. Mag. 52 (2003) 251-258