1. Hal Gordon CSIRO Atmospheric Research, Aspendale, Australia CSIRO Mk3 Climate Model: Tropical Aspects

2. CSIRO Mk3 Model Atmosphere Grid:T63 (1.88 0 x 1.88 0 ) 18 levels - hybrid ,p Semi-Lagrangian moisture transport UKMO convection (Gregory & Rowntree) Liquid water clouds (Rotstayn) Dissipation  Heating plus …….

3. CSIRO Mk3 Model Land surface Soil model - 6 levels Temperature, water, ice 9 soil types 13 land surface and/or vegetation types Snow-cover model - 3 layers Sea ice Flato-Hibler rheology Semtner thermodynamics (3 level) Variable leads + lateral ice growth

4. CSIRO Mk3 Model Ocean GFDL MOM 2.2 Grid: 0.94 0 NS x 1.88 0 EW (AGCM = 1.88 0 x1.88 0 ) 31 levels (10m surface  400m deep ocean) Shear mixing: “Integer Power” R i Surface mixing: Bulk R i Griffies et al. (1999) isoneutral mixing Griffies (1999) skew diffusion for GM90 “Quick” third-order advection Penetrating solar / Jerlov(1977) water types No flux adjustment

5. Mk 3 Computational Requirements: Integration on NEC SX5 About 1 model year per day using 4 processors Data storage per model year: 1.2Gb approx. Reference: Gordon et al. (2002) CSIRO Atmos. Res. Tech. Paper 60 (www.dar.csiro.au)

6. OGCM Spin-up: 1000 years (accelerated) 10 years Relaxation (6 day) to Levitus T & S Surface stresses from AGCM AGCM Spin-up: 120 years. Coupled Mk3 model: Synchronous coupling. Initial states from Spin-ups above. Instant coupling - some adjustment to be expected.

8. Next: A “warts and all” look at the Mk3 coupled model in the tropics. 1st: Annual mean stresses and surface currents

9. Zonal stress

10. Meridional stress

13. OGCM spin up Coupled

14. Next: Zonally averaged heat and fresh water flux: OGCM during spinup AGCM before coupling CGCM

17. Surface heat flux

20. Fresh water flux

21. Next: Ocean surface temperature and salinity responses:

25. Next: Pacific thermocline:

26. Levitus OGCMCoupled Annual mean temperature (upper 400m) along equator in Pacific Ocean

27. T @150W (15S:15N) Obs OGCMCoupled

28. Tropical sea level pressure; Global rainfall:

29. Obs Annual mean sea level pressure

30. Observed and Mk3 AGCM rainfall (DJF)

31. Observed and Mk3 coupled rainfall (DJF)

32. Observed and Mk3 AGCM rainfall (JJA)

33. Observed and Mk3 coupled rainfall (JJA)

34. Annual mean precipitable water content (PWC)

37. Observed and CSIRO modeled monthly rainfall over NE Australia

38. Nino3.4

39. CSIRO modeled and observed temperature anomalies over NINO3 region NINO3 region: E. Pacific (150W-90W, 5N-5S)

40. Power spectrum of the modeled and observed Niño3.4 index (5% and 95% confidence levels and a”red-noise” fit are overlaid.)

41. Excessive cold tongue is evident in the OGCM spin-up It amplifies on coupling, extending west Tropical stresses look “reasonable” - but? Tropical heat flux less so (AGCM & CGCM) Fresh water flux seems ok Rainfall split by cold tongue (coupled) Nino3.4 SST anomalies of correct(+) magnitude Issues - Drift - North Atlantic behaviour (Gulf Stream*) - Tropical Pacific climatology (e.g., excessive penetration of cold tongue) Summary of Mk3 results

42. Some actual words (truth) from the Minister for Information, Mohammed Saeed Al-Sahaf (“Comical Ali” ), being skeptical as ever, even about climate modelling: How good are current climate models? “I now inform you that you are too far from reality.” How far from reality around Baghdad? "They're not even within 100 miles. They are not in any place. They hold no place in Iraq.” What about Middle East climate change? “This is an illusion... they are trying to sell to the others an illusion.” Finally, are you worried about the Pacific cold tongue? "No, I am not scared and neither should you be!" End