Evaluation of Insect Monitoring Radar Technology for Monitoring Locust Migrations in Inland Eastern Australia Haikou Wang A thesis submitted for the degree of Doctor of Philosophy in the Faculty of UNSW@ADFA The University of New South Wales 31 July 2007 Originality Statement I hereby declare that this submission is my own work and to the best of my knowledge it contains no material previously published or written by another person, or substantial proportions of material which have been accepted for the award of any other degree or diploma at UNSW or any other educational institution, except where due acknowledgment is made in the thesis. Any contribution made to the research by others, with whom I have worked at UNSW or elsewhere, is explicitly acknowledged in the thesis. 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Haikou Wang 31 July 2007 v Evaluation of Insect Monitoring Radar Technology for Monitoring Locust Migrations in Inland Eastern Australia Haikou Wang A thesis submitted for the degree of Doctor of Philosophy in the Faculty of UNSW@ADFA The University of New South Wales 31 July 2007 vii 0 Abstract To evaluate the utility of insect monitoring radar (IMR) technology for long-term monitoring of insect migration, a mini-network of two IMR units in Bourke, NSW, and Thargomindah, Qld, and a base-station server in Canberra, ACT, was set up in eastern Australia. The IMR operated automatically every night under the control of a personal computer that also conducted data acquisition and processing. Digitisation of radar signals, their analysis (delimitation of echoes from background noise and adjoining echoes, followed by extraction of estimates for each target’s speed, displacement direction, body alignment, radar cross-section, and wingbeat frequency and modulation pattern), and generation of observation summaries were implemented as a fully automated procedure. Wingbeat frequency was found to be retrievable from the IMR’s rotary-beam signals, and this allowed each individual target to be characterised by its wingbeat as well as its size and shape. By drawing on ancillary information from the Australian Plague Locust Commission’s database of field survey and light trap records, the echo characters indicative of Australian plague locust, Chortoicetes terminifera (Walker), were identified. Using these, about 140 nights with detectable plague locust migrations were identified for the Bourke IMR site during 1998 – 2001 and 31 nights for Thargomindah during 1999 – 2000. Analysis of these nights confirmed that C. terminifera migrates in association with disturbed weather, especially tropical troughs, in eastern Australia. Trajectory simulation based on IMR-derived displacement directions and flight speeds allowed the identification of population movements likely to reach favourable habitats and thus to develop rapidly and possibly cause a plague. The outbreak during 1999 – 2001 most likely originated from the southeastern agricultural belt after migrations and multiplications over several generations. The IMR observations demonstrated that C. terminifera migrates over long distances with the ix x Abstract wind at night and indicated that it may have an orientation behaviour that prevents it from being taken too far into the arid inland, a trait that could be highly adaptive in this environment. The two IMRs were operational for more than 85% of scheduled time during the study period and provided a wealth of information of potential value for locust management and migration research. Acknowledgments I am in debt to my supervisor, Dr Alistair Drake, whose inspiration and encouragement have endeavoured me to explore the unknown radar world where I finally can see the insects migrating in the darkness over hundreds of kilometres away in the remote inland eastern Australia. I would like to express my appreciation to Prof Xianian Cheng, my MSc supervisor, who has introduced me to this fantastic field of insect migration. I also wish to register my profound gratitude to Prof Joe Riley, Dr Don Reynolds, and Mr Alan Smith. Working with them intensively near rice fields in China at night, I was impressed by their pioneer adventure, work attitude, knowledge and skills, all directed at discovering the mysterious migration mechanisms. I especially want to thank my fellow students, Ian Harman and Tim Dean, for the friendship, joyful cooperative work experience, invaluable contributions and assistance during my study. Thanks also go to the School of Physical, Environmental and Mathematical Sciences and their support staff who made my work easier, and the Australian Plague Locust Commission where I had the access to facilities and resources vital to my research project and helpful discussions about plague locust migrations with Dr David Hunter and Mr Ted Deveson. Generous scholarship support from the Australian Government (Australian Research Council Large Grant and Australian Government International Postgraduate Research Scholarship) and UNSW@ADFA made my study possible. Finally, I thank my wife, Min, and my son Yineng, for their understanding, patience and encouragement. Without their support and tolerance, I would not be able to finish my study. xi Table of Contents ABSTRACT................................................................................................................................IX 1 INTRODUCTION ............................................................................................................... 1 1 INSECT MIGRATION .......................................................................................................... 3 1.1 Definition of Migration .......................................................................................... 3 1.2 Boundaries of the Lower Atmosphere .................................................................... 4 1.3 Advances in the Studies of Insect Migration .......................................................... 6 1.4 Monitoring and Forecasting Migration ................................................................. 8 2 RADAR ENTOMOLOGY .................................................................................................... 14 2.1 Radars in Use for Entomological Purposes......................................................... 15 2.2 Advances in Technological Development............................................................. 19 2.3 Advances in Applications ..................................................................................... 22 3 INSECT MIGRATIONS IN EASTERN AUSTRALIA................................................................ 35 3.1 Environments of Eastern Australia ...................................................................... 36 3.2 Key Migratory Insects.......................................................................................... 38 4 STRUCTURE OF THE THESIS............................................................................................. 41 2 THE AUSTRALIAN IMR MINI-NETWORK ............................................................... 43 1 INTRODUCTION ............................................................................................................... 44 2 THE MINI-NETWORK STRUCTURE AND ITS COMPONENTS .............................................. 45 2.1 The Mini-Network Structure ................................................................................ 45 2.2 The IMR Hardware .............................................................................................. 47 3 THE SOFTWARE IMPLEMENTATION ................................................................................. 51 3.1 The IMR Operation .............................................................................................. 53 3.2 The AWS Operation ............................................................................................. 55 3.3 Extraction of Target Parameters.......................................................................... 56 3.4 Statistics of Observation Results.........................................................................