Seasonal Prediction System and Applications at the Australian Bureau of Meteorology

1. Seasonal Prediction System and Applications at the Australian Bureau of Meteorology Guomin Wang With contributions from Harry Hendon, Oscar Alves, Claire Spillman, Faina Tseitkin and Xiaobing Zhou Centre for Australian Weather and Climate Research:A partnership between the Bureau of Meteorology and CSIRO

2. Outline • POAMA (Predictive Ocean Atmosphere Model for Australia) & a brief update on ACESS • Great Barrier Reef SST Prediction • Leeuwin Current Prediction

3. POAMA Overview • The Bureau Dynamical Seasonal Prediction System POAMA • First version went operational in 2002 • A new version (POAMA1.5) became operational recently and a newer version is in development • POAMA development evolves as part of Australian Earth System Modelling project ACCESS • WebpagePOAMA.BOM.GOV.AU

4. POAMA Model Components Atmospheric Model BAM T47L17 -> T63L17 -> ACCESS(UKMO+LSM) 3h OASIS Coupler time Heat flux, P-E Ocean Model ACOM2 lat/lon/lev=0.5~1.5/2/25 -> AusCOM

5. Hindcasts Design • Control run initialized at 00Z on the first day of each month, 1980-2006 • Extra 9 members initialized prior to control run initial time in progressively 6 hours interval • Each hindcast is integrated for 9 months

6. Skill Assessment: ACC for SST and Heat Content SST H300 +1 +3 +5

7. Skill Assessment: ACC for SST Pacific & Indian Ocean Indices Nino3.4 IOD ACC RMS

8. ACCESS: The Australian Community Climate and Earth System Simulator Atmosphere Coupler CABLE AusCOM Ocean (MOM4p1 code) AusCOM Sea ice (CICE4 code) Coupled Modelling Team Land Surface/Carbon Cycle Team Model Systems Team Atmospheric Modelling Team Kamal Puri

9. ACESS Component Model Testing: UM UM OBS BAM

10. ACESS Component Model Testing: AusCOM AusCOM GODAS Zonal annual mean velocity (1990-2001) along the equator (X Zhou)

11. Claire Spillman The Great Barrier Reef • Largest coral reef system in the world • Habitat for richly diverse community of species • Sporadic bleaching in GBR since 1982 • Mass bleaching events in 1998 & 2002

12. Claire Spillman Coral bleaching & what we can do • Loss of symbiotic algae (zooxantheallae) from coral tissues during times of stress • High SST is primary cause of bleaching • Mortality increases with frequency, duration & magnitude of high temperatures • Bleaching in the GBR tends to occur Feb-April • Satellite based now-casts e.g. NOAA Coral Reef Watch Program • Advance warning assists management • Improve recovery times by reducing stress on affected areas e.g. limited access Image courtesy of GBRMPA

13. Claire Spillman GBR SST Index • Mean SST anomalies in GBR region • Model captures general variability 0.81 0.81 0.63 0.63 0.55 0.55 0.46 Spatial correlation of GBR Index Spillman & Alves, 2008 0.46

14. Claire Spillman GBR SST Index Skill • Predictability: Maximum skill limit (perfect model assumption) SST anomaly correlations Spillman & Alves, 2008

15. Claire Spillman Coral Bleaching HotSpots http://coralreefwatch.noaa.gov • Anomalies calculated using maximum monthly climatology 1982-2006 • Coral bleaching events often noted in areas where HotSpots > 1oC obs Feb 2002 Lead=0 model

16. Claire Spillman Degree Heating Weeks http://coralreefwatch.noaa.gov obs • Indicates accumulation of thermal stress that coral reefs have experienced over past 12 weeks • DHW = Sum (Weekly Hotspots) over last 12 weeks • Depict the duration and strength of thermal stress that results in bleaching. • Severe coral bleaching likely where DHW > 10 obs model

17. Claire Spillman Model BleachingProducts obs obs • Weekly products • Combine with GBR Index? • How best to assess skill? model obs model

18. Claire Spillman Example GBR Forecasts • Daily forecasts produced in real time • Used by GBRMPA with ReefTemp http://poama.bom.gov.au http://www.cmar.csiro.au/remotesensing/ gbrmpa/ReefTemp.htm

19. Seasonal Prediction of the Leeuwin Current: Observed Features Freemantle sea level (FSL) is indicative of volume transport variation of the Leeuwin Current (M. Feng). Use FSL as a proxy for Leeuwin Current strength.

20. Annual Mean of SST & top 300m Currents from Reanalyses

21. Annual Mean of V-Current along 32ºS from Reanalyses

22. Pattern Correlation of V anomalies along 32ºS from Reanalyses 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 Years

23. Fremantle Sea Level and Ocean Heat ContentObservation vs Forecast Skill Obs relationship between H300 and SLA at Freo HCNW = 15-25ºS,112-120ºE H300 ACC Skill at leadtime=7

24. Fremantle Sea Level and SSTObservation vs Forecast Skill N34 = 5ºS-5ºN; 170º-120ºW

25. Downscaling POAMA Forecasts to Fremantle SLA

26. Skill of Fremantle SLA Prediction from Downscaling Scheme Nino4 NWHC Both Combined Persist

27. FSLA Forecasts 1982-2006 FSLA Obs FSLA Lead 3 FSLA Lead 6 FSLA Lead 9 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 Years

28. Summary • Introduction of the Australian Bureau’s Dynamical Seasonal Prediction System POAMA and ACCESS • Exploring potential for regional SST forecast products (Great Barrier Reef) with dynamical system • Challenge for regional ocean current simulation and prediction. A downscaling scheme with dynamical model inputs shows useful skill for the Leeuwin Current.