Dust transportation and deposition in a superhumid environment, West Coast, South Island, New Zealand

Contemporary rates of dust deposition monitored along a 300-km section of the superhumid West Coast of New Zealand's South Island are presented. In this setting, dust is entrained primarily from the dry channels of braided glaciofluvial rivers that drain the western slopes of the Southern Alps. Measured dust deposition ranged between 0.21 and 118.9 kg−1 ha−1 month−1, which is similar to dust deposition rates monitored in arid and semiarid environments. However, these are not considered to be sufficient for present day loess genesis. Dust deposition was highest in summer because of the greater frequency of favourable dust transporting winds, and the effect of rainfall was secondary. Dust transportation occurred mainly during the passage of nonprecipitating cold fronts or postfrontal southwesterlies. Transportation also occurred during prefrontal conditions, and in winter föhn southeasterlies were the predominant dust transporting winds to affect the West Coast.