The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology Ocean Model, Analysis and Prediction System: version 2 G.B. Brassington, J. Freeman, X. Huang, T. Pugh, P.R. Oke, P.A. Sandery, A. Taylor, I. Andreu-Burillo, A. Schiller, D.A. Griffin, R. Fiedler, J. Mansbridge, H. Beggs and C.M. Spillman CAWCR Technical Report No. 052 April 2012 Ocean Model, Analysis and Prediction System: version 2 G.B. Brassington, J. Freeman, X. Huang, T. Pugh, P.R. Oke, P.A. Sandery, A. Taylor, I. Andreu-Burillo, A. Schiller, D.A. Griffin, R. Fiedler, J. Mansbridge, H. Beggs and C.M. Spillman The Centre for Australian Weather and Climate Research - a partnership between CSIRO and the Bureau of Meteorology CAWCR Technical Report No. 052 April 2012 ISSN: 1836-019X National Library of Australia Cataloguing-in-Publication entry Author: G.B. Brassington, J. Freeman, X. Huang, T. Pugh, P.R. Oke, P.A. Sandery, A. Taylor, I. Andreu-Burillo, A. Schiller, D.A. Griffin, R. Fiedler, J. Mansbridge, H. Beggs and C.M. Spillman Title: Ocean Model, Analysis and Prediction System: version 2 ISBN: 978 0 643 10843 1 (Electronic Resource) Series: CAWCR technical report; 52 Subjects: Notes: Included bibliography references and index Other Authors / Contributors: Day, K.A. (Editor) Enquiries should be addressed to: Dr Gary Brassington Centre for Australian Weather and Climate Research: A partnership between the Bureau of Meteorology and CSIRO GPO Box 1289, Melbourne Victoria 3001, Australia [email protected] Copyright and Disclaimer © 2012 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. Cover image: Sea level anomaly for the 20th January 2012 over the Australian region from the analysis cycle of the OceanMAPSv2. (J. Freeman) Contents Abbreviations and Symbols.......................................................................................vii 1. Abstract ..................................................................................................................1 2. Introduction............................................................................................................2 3. System description ...............................................................................................4 3.1 Real-time ocean observing system ........................................................................... 4 3.1.1 Satellite altimetry....................................................................................................... 5 3.1.2 Satellite Sea Surface Temperature ........................................................................... 8 3.1.3 In situ profiles and duplicate checker ...................................................................... 12 3.2 In-situ quality control system ................................................................................... 15 3.2.1 Internal stage: Analysis of current in situ profile...................................................... 16 3.2.2 External stage: Analysis of current in situ profile..................................................... 17 3.3 Ocean general circulation model............................................................................. 19 3.3.1 Grid specification..................................................................................................... 19 3.3.2 SPINUP mean dynamic topography........................................................................ 27 3.3.3 SPINUP variability................................................................................................... 27 3.4 Ocean data assimilation system.............................................................................. 27 3.4.1 Options.................................................................................................................... 27 3.4.2 Super observations ................................................................................................. 27 3.4.3 Background error covariance .................................................................................. 27 3.4.4 Observation error covariance.................................................................................. 27 3.5 Initialisation.............................................................................................................. 27 3.6 Surface forcing......................................................................................................... 27 3.6.1 Atmospheric fluxes.................................................................................................. 27 3.6.2 Pre-processing and regridding ................................................................................ 27 3.6.3 River discharge ....................................................................................................... 27 3.7 Forecast system design........................................................................................... 27 3.8 Computational design.............................................................................................. 27 4. Results..................................................................................................................27 4.1 Bias.......................................................................................................................... 27 4.2 Observation statistics .............................................................................................. 27 4.3 Analysis statistics..................................................................................................... 27 4.4 Forecasts statistics .................................................................................................. 27 4.5 Sensitivity of performance ....................................................................................... 27 4.6 Independence of the multi-cycle forecasts .............................................................. 27 4.7 Multi-cycle lagged ensemble forecasting ................................................................ 27 5. Conclusions .........................................................................................................27 6. Acknowledgments...............................................................................................27 7. References ...........................................................................................................27 Appendix A OFAM2 options ...........................................................................27 Appendix B BODAS2 options.........................................................................27 Appendix C Continuity of fluxes across land-Sea masks ...........................27 Appendix D in situ Quality control metadata................................................27 Ocean Model, Analysis and Prediction System: version 2 i List of Figures Fig. 1. The spatial coverage of three narrow-swath altimeters (Jason1, ENVISAT and Jason2) over the Tasman Sea for 15 March 2011. The tracks are plotted using a colour for the observed SSHA and overlayed on a background field of the 24hr average SSHA from the behind real-time analysis cycle relative to the modelled mean dynamic topography. The four plots represent the coverage for different symmetric time windows from the target date, (a) +/-0 days, (b) +/- 1 days, (c) +/- 3 days and (d) +/- 5 days. ................................................................................................. 7 Fig. 2. The spatial coverage for Jason 2 using a window of +/- 5 days over the Tasman Sea for 15 March 2011. The tracks are plotted using a colour for the observed SSHA and overlayed on a background field of the 24hr average SSHA from the behind real-time analysis cycle relative to the modelled mean dynamic topography.... 8 Fig. 3. Estimation of the mean diurnal bias (ascending minus descending) between collocated pairs of AMSR-E observations from the ascending and descending passes, (a) Austral summer (1 Nov 2006 - 28 Feb 2007) and (b) Austral winter (1 June 2006 - 31 August 2006). ................................................................................. 10 Fig. 4. Bins that satisfy the ascending swath contribution criterion, >30% of the time the ascending is the only observation and the mean absolute bias of ascending minus descending is <0.2 °C. (a) Austral summer (1 Nov 2006 - 28 Feb 2007) and (b) Austral winter (1 June 2006 - 31 August 2006) ........................................................... 11 Fig. 5. A time series