A re-examination of the 1928 trans-Tasman dust transport event | The Meteorological Society of New Zealand

A re-examination of the 1928 trans-Tasman dust transport event

S.K. Marx
H.A. McGowan

This paper presents a re-examination of the meteorology of the largest reported Australian dust fall, when in 1928 up to 206 g m2 of dust was deposited over a four day period throughout much of New Zealand. Two contrasting explanations of the meteorology of the event have been offered; initially that dust transport took place within a series of extra-tropical cyclones and associated troughs; and the second forty years latter, that the dust was transported across the Tasman Sea in the upper-troposphere and lower stratosphere embedded within a jet stream. Re-analysis of observations made during the event, combined with recent studies of the nature of inter-regional dust transport suggests that the latter explanation of high-level transport is not valid. Examination of synoptic charts show that the deposition of dust in New Zealand in October 1928 resulted from four separate dust storms in eastern Australia. These were the result of the passage of successive cold fronts during a period of drought. It is argued that these fronts transported dust at low levels across the Tasman Sea rather than at high levels in the troposphere.

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