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Climate Modelling in Australia Michael Manton Bureau of Meteorology Research Centre APN Symposium, 23 March 2004
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Climate models capture the complexity of the climate system
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Why is climate modelling important? ● World Climate Research Programme (WCRP) in 1980 recognised the climate model as the tool to – Simulate climate system and its components – Test understanding of climate system – Combine observations in a consistent manner – Simulate past climate variations and changes – Predict future climate variations and changes
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Australia has a long history of involvement in climate modelling ● Universities – Macquarie – Land surface modelling – Melbourne – Southern hemisphere phenomena – Monash – Detection of climate change – NSW – Ocean modelling – Tasmania – Sea ice modelling ● Government agencies – ANSTO – Isotopes & land surface – CSIRO – Weather and climate – BMRC – Weather and climate
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There is substantial collaboration between groups ● Cooperative Research Centres – Antarctic Climate & Ecosystems ● Collaborative projects – CSIRO & BMRC with AGO – CSIRO & BMRC with WA Government ● Australian Academy of Science – NCESS workshop ● Australian Research Council – Network on ESM
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Some Examples ● Model validation of land surface schemes – Macquarie University and BMRC ● Use of isotopic data to validate models – ANSTO ● Coupled modelling for inter-annual prediction – BMRC and CSIRO Marine Research ● Coupled modelling for climate change – CSIRO Atmospheric Research
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Surface Energy Complexity Does it matter in climate models? ● Macquarie University and BMRC ● AMIP-2 result analysis ● Using CHASM (captures various levels of surface energy balance [SEB] complexity) ● See Pitman et al., GRL, 2004, in press
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Colour = various modes of CHASM Thick black line = observed Thin black lines = AMIP-2 model results No systematic differences: SEB does not explain AMIP-2 differences Zonal differences in simulated temperature variance Results give confidence in climate model projections of basic values
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Maximum temperature variance Most complex mode – Includes tiling … Tiling leads to significantly higher maximum temperatures Results imply SEB complexity affects extreme values
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AMIP2 Analysis ● Prediction of land surface climate evolved over time. ● Not always forwards ● Schemes capture a wide range of behaviours. ● Not all schemes equally good. No canopy ‘SiB’lings others Henderson-Sellers et al. 2003 (Geophys. Res. Lett. 30,1777 )
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Isotope model studies ● Emerging area for model studies ● Independent validation tool ● ARC Linkage & other funding agencies 1980s 18 O in 1960s & 1980s Weakened signal at Manaus means more water-recycling.Weakened signal at Manaus means more water-recycling. Other indicators say more non-fractionating sources.Other indicators say more non-fractionating sources. H-S, McGuffie & Zhang, J. Clim., 2002, 15, 2664 ANSTO
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POAMA Predictive Ocean Atmosphere Model for Australia ● Global coupled model GCM seasonal forecasting system ● Joint project between BMRC and CSIRO Marine Research ● Partly funded by the Climate Variability in Agriculture Program (CVAP) ● Run in real-time by Bureau operational section since 1 October 2002 ● Operational products issued by the Bureau National Climate Centre (NCC) ● Experimental products available on the POAMA web site www.bom.gov.au/bmrc/ocean/JAFOOS/POAMA
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Introduction- POAMA operational system Ocean assimilation - Temp. OI every 3 days + current corrections Daily NWP Atmos. IC Atmos. Model T47 BAM (unified) Ocean Model ACOM2 (~MOM2) Coupler: OASIS Atmospheric observations Ocean observations Real-time ocean assimilation latest ocean/ atmos obs 9-month forecast once per day Ensemble forecasts Observing networkObs/data AssimilationModelForecast/products
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Skill of SST Predictions Green - model, red - anomaly persistence Hind-casts: one forecast per month, 1987-2001 (180 cases) Anomaly correlation
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Anomaly Correlation 2 months 6 months 4 months
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Decay of 2002 El Nino POAMA Real-time forecasts correctly predict decay Prepared P. Reid NCC
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Sample OLR intra-seasonal forecast from POAMA-1 5-member ensemble starting 10 Dec 2003 MJO Days 1-5 Days 6-10 Days 11-15 Days 16-20 Days 20-30 Days 30-40
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CSIRO Atmospheric Research CSIRO Mark 3 model 3-dimensional global model 18 levels in atmosphere 31 levels in ocean including sea-ice 6 soil levels, 9 soil types, 13 vegetation types 3 snow levels 180 km between grid-points (100 km in tropics to better simulate El Nino) Data for 100 climate variables computed in 30-minute time-steps for a series of months, years decades or centuries Models adequately simulate observed daily weather and average climate patterns A one-year simulation takes 1 day of computer time
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Improved simulation of El Nino Southern Oscillation Observed sea surface temperature anomaly CSIRO Mark 2 model CSIRO Mark 3 model
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CSIRO Mark 3 simulation 1870-2020+ Global surface air temperature change
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Model hierarchy Global climate model (grid: 180 km by 180 km) Regional climate model (grid: e.g. 70 km by 70 km) Regional climate model (grid: e.g. 14 km by 14 km) Statistical downscaling (local sites: e.g. Perth) PC software, e.g. MAGICC, OzClim ComplexSimple
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Modelled and Observed Mean Winter and Spring Rainfall, years 1961-1975 CSIRO Cubic Conformal Atmospheric Model – stretched grid
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OzClim PC software Database includes: Observed and simulated monthly-average data on 25 km grid 10 climate models 6 IPCC emission scenarios 3 climate sensitivities 9 climate variables Functions: Plot maps and global warming curves Save regional average data Run simple impact models Package is used for impact studies and education
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New components developed and tested separately, then coupled in the model and tested again Land surface Ocean IPCC 2001
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Future Directions ● Enhanced complexity ● Improved parameterisations ● Improved representation of external forcings ● Improved understanding of predictability ● Analysis of extreme events ● Use of ensembles to represent uncertainty ● Coupling of economic and climate models
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