Duncan Cook

A small unmanned aerial system (UAS) for coastal atmospheric research: preliminary results from New Zealand

Abstract Experiments conducted in the low-altitude coastal atmosphere in New Zealand have demonstrated the potential of a new unmanned aerial system (UAS) for meteorological research. The Kahu unmanned aerial vehicle flies autonomously using GPS and pre-programmed waypoints, collecting observations of air temperature and relative humidity that are relayed to a ground-station near-instantaneously. Experiments conducted in the Hauraki Gulf, Auckland, show that the Kahus radio transmission system can successfully transmit data across the ocean surface at distances up to 25 km. Accuracy of the meteorological data collected by the UAS was assessed via a direct comparison with weather station sensors and radiosonde soundings at heights of up to 500 m in the Bay of Plenty. Close agreement between the UAS, radiosonde and weather station data suggests that the Kahu UAS has considerable scope as a new field research tool in New Zealand, capable of providing reliable atmospheric data that can complement and even supplement conventional low-altitude sampling techniques.

Somali Piracy and the Monsoon

AbstractAnalysis of the weather and ocean conditions during recent pirate attacks in the Indian Ocean region suggests that the transition of the summer monsoon limits maritime piracy. A comparison of all known pirate attacks in the region in 2010–11 with surface observations from Socotra and the Somali jet index during the same period indicates that pirates attacking from skiffs are thwarted when winds blow in excess of 9 m s−1. The wind speeds and sea states encountered by pirates during individual attacks were reconstructed using satellite altimetry data for 2010–11. Mean daily wind speeds of up to 20 m s−1 during the two boreal summers resulted in consistently rough seas across the Arabian Sea and Indian Ocean. Surface wind speeds during pirate attacks were generally low (less than 8 m s−1), and once wind speeds exceeded 9 m s−1 no successful attacks occurred. The majority (94%) of pirate attacks took place in waves of sea state 4 or less (wave heights below 2.5 m), with pirates rarely attacking after ...

On 90 years of Australian Geographer, and beyond

This issue of Australian Geographermarks the journal’s 90th anniversary. It comes at a time of great change, reflection, and possibility—for geography, and for the earth. Over the past nine decades, ideas and methods in geography have evolved considerably. The very first issue of Australian Geographer, published in August 1928, might be considered an antiquity of the prevailing colonial imaginary. In their inaugural editorial, Stead and Taylor (1928, 3–4) positioned the journal, and the newly formed Geographical Society of New South Wales, as an essential platform for ‘nation-planning’: