An automated procedure for the identification of synoptic types applied to the new zealand region

✍ Scribed by John W. Kidson

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 884 KB
• Volume: 14
• Category: Article
• ISSN: 0899-8418
• DOI: 10.1002/joc.3370140702

✦ Synopsis

Abstract

Cluster analysis has been applied to 9 years of daily 1000 hPa analyses for 1980–1988 over the New Zealand region. The resulting 13 synoptic groupings are characterized mainly by high‐pressure cells and pressure gradients reflecting the predominant wind directions. Low‐pressure centres are not well represented, presumably because of their smaller horizontal scale and lower frequency of occurrence.

Seasonal variations in cluster frequency over this period typically differ by a factor of two. The most persistent patterns are associated with highs to the south of New Zealand, whereas the transitions between clusters show the familiar sequence of eastward‐propagating high‐pressure cells interspersed with troughs.

It is anticipated that these synoptic classifications will prove helpful in interpreting inter‐annual climate fluctuations, in validating the performance of climate models for the New Zealand region and in providing improved guidance to forecasters. Their application to the analysis of daily and monthly variations in climatic elements is described in a companion paper.