15th Conf on Biometeorology and Aerobiology and the 16th International Congress of Biometeorology

Wednesday, 30 October 2002: 1:15 PM
Wind, aeolian sediment, and plant damage on Heard Island
Paul J. Beggs, Macquarie University, Sydney, NSW, Australia; and P. M. Selkirk and D. L. Kingdom
Heard Island (73°30'E, 53°05'S) is an isolated island in the Subantarctic. The island is 42 km long and 20 km wide, and covers an area of approximately 385 km2. The dominant topographic feature is a large glaciated volcano, Big Ben, which peaks at 2,745 m in altitude. The island's latitude places it in a region of strong westerly winds. Only limited meteorological information exists for the island, with incomplete records from a station at Atlas Cove covering the period 1948 to 1954, and from a station at The Spit from 1992 onwards. These records indicate there are frequent strong and gale force winds, and observations on the island suggest these result in excessive production of aeolian sediment. Other observations of vegetation have suggested that this aeolian sediment may contribute to significant plant damage in certain locations.

This paper presents the results of wind, sediment and vegetation observations that were conducted on Heard Island over the 2000/2001 summer, with the aim of characterising local winds at a number of locations on the island, and relating these to the observed aeolian sediment and vegetation damage at these locations.

Wind was measured using Woelfle Type Mechanical Wind Recorders at four locations on the island: three at the western end of the island and one at the eastern end. Winds at these four locations are plotted and characterised. Four samples of aeolian sediment were also collected, along with information related to plant damage at each of the sites.

Wind speed was generally strongest at the eastern end of the island, where winds were predominantly from the SSW or NW-N. Of the three western end locations, winds on Azorella Peninsula (to the NE of Atlas Cove) were strongest, coming predominantly from the S to SW sector, while those on the eastern slope of Mt Aubert de la Rue were lowest and came from the NNW or ESE sectors.

Results from this study suggest there are significant topographically-generated differences in the wind characteristics at the four sites examined. Wind is clearly relate to the occurrence of aeolian sediment, which is in turn related to physical plant damage on the island.

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