The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology A High-quality Historical Humidity Database for Australia Chris Lucas CAWCR Technical Report No. 024 July 2010 A High-quality Historical Humidity Database for Australia Chris Lucas1 1The Centre for Australian Weather and Climate Research - a partnership between CSIRO and the Bureau of Meteorology CAWCR Technical Report No. 024 July 2010 ISSN: 1835-9884 National Library of Australia Cataloguing-in-Publication entry Author: Lucas, Chris. Title: A High-quality Historical Humidity Database for Australia [electronic resource] / Chris Lucas. ISBN: 9781921605864 (pdf) Series: CAWCR technical report; 24. Notes: Included bibliography references and index. Subjects: Humidity--Australia--Databases. Meteorology--Australia--Databases. Australia--Climate. Dewey Number: 551.5710994 Enquiries should be addressed to: Chris Lucas Centre for Australian Weather & Climate Research GPO Box 1289 Melbourne Victoria 3001, Australia [email protected] Copyright and Disclaimer © 2010 CSIRO and the Bureau of Meteorology. To the extent permitted by law, all rights are reserved and no part of this publication covered by copyright may be reproduced or copied in any form or by any means except with the written permission of CSIRO and the Bureau of Meteorology. CSIRO and the Bureau of Meteorology advise that the information contained in this publication comprises general statements based on scientific research. The reader is advised and needs to be aware that such information may be incomplete or unable to be used in any specific situation. No reliance or actions must therefore be made on that information without seeking prior expert professional, scientific and technical advice. To the extent permitted by law, CSIRO and the Bureau of Meteorology (including each of its employees and consultants) excludes all liability to any person for any consequences, including but not limited to all losses, damages, costs, expenses and any other compensation, arising directly or indirectly from using this publication (in part or in whole) and any information or material contained in it. CONTENTS Contents..........................................................................................................................i List of Figures ..............................................................................................................iv List of Tables...............................................................................................................vii Abstract..........................................................................................................................1 1 Introduction..........................................................................................................3 2 Homogenization in brief......................................................................................4 3 Data .......................................................................................................................5 3.1 Candidate stations.................................................................................................... 5 3.2 Reference Stations ................................................................................................... 7 4 Dewpoint Computation and Measurement......................................................10 4.1 Psychrometric Method............................................................................................ 10 4.2 Humidity Instruments used by the Bureau ............................................................. 11 5 Quality Control and Homogenization...............................................................13 5.1 Recomputing dewpoint ........................................................................................... 13 5.2 Error identification and removal.............................................................................. 13 5.3 The details of homogenization................................................................................ 16 6 Results................................................................................................................30 6.1 General comments on homogenization.................................................................. 30 6.2 Comparison with the metadata............................................................................... 34 6.3 Comments on the methodology.............................................................................. 38 6.4 Validity of the results............................................................................................... 39 6.5 A few words about usage ....................................................................................... 46 7 A Preliminary Humidity Climatology of Australia ...........................................46 7.1 Monthly Median Maps............................................................................................. 46 7.2 Graphs of Monthly Dewpoint distributions.............................................................. 50 7.3 Interannual variability.............................................................................................. 70 7.4 Regional Variability................................................................................................. 73 7.5 Long-term Trends in Dewpoint ............................................................................... 77 8 Summary and Conclusions...............................................................................81 9 References .........................................................................................................83 10 Appendix A. Homogenization Details by Station............................................85 10.1 Adelaide.................................................................................................................. 86 i 10.2 Albany .....................................................................................................................87 10.3 Alice Springs ...........................................................................................................88 10.4 Amberley.................................................................................................................89 10.5 Bendigo...................................................................................................................90 10.6 Birdsville..................................................................................................................91 10.7 Bourke.....................................................................................................................92 10.8 Brisbane AP ............................................................................................................93 10.9 Broome....................................................................................................................94 10.10 Cabramurra.............................................................................................................95 10.11 Cairns......................................................................................................................96 10.12 Camooweal .............................................................................................................97 10.13 Canberra .................................................................................................................98 10.14 Cape Leeuwin .........................................................................................................99 10.15 Carnarvon .............................................................................................................100 10.16 Ceduna..................................................................................................................101 10.17 Charleville .............................................................................................................102 10.18 Cobar ....................................................................................................................103 10.19 Coffs Harbour........................................................................................................104 10.20 Darwin...................................................................................................................105 10.21 Dubbo....................................................................................................................106 10.22 Esperance.............................................................................................................107 10.23 Forrest...................................................................................................................108 10.24 Galiwinku...............................................................................................................109 10.25 Geraldton ..............................................................................................................110 10.26 Giles ......................................................................................................................111 10.27 Hobart ...................................................................................................................112 10.28 Kalgoorlie ..............................................................................................................113 10.29 Kalumburu.............................................................................................................114