The correlation between climatic parameters and the retreat and advance of Franz Josef Glacier, New Zealand

After a long period of general retreat, the Franz Josef Glacier on the western flanks of the Southern Alps of New Zealand has undergone a major advance, beginning about 1982. Key climatic variables, atmospheric circulation patterns over the Southwest Pacific, and the Southern Oscillation Index (SOI), are compared for two 20-year periods that represent advance and retreat phases of the Franz Josef Glacier. The results show strong links between atmospheric circulation changes, climate variables and glacier behaviour. The retreat phase is characterised by slightly warmer temperatures and markedly lower precipitation in the ablation season, a high pressure anomaly over New Zealand, and a southward shift in the subtropical high pressure zone. In contrast, the advance phase is characterised by anomalous southwest airflow, especially during the ablation season, and higher precipitation. The high pressure anomaly is shifted westward by about 55° of longitude so as to lie south of Australia. The advance phase is also related to a higher frequency of El Niño events.