1 CUTTING-EDGE CLIMATE SCIENCE AND SERVICES Geoff Love

2 An essential task of the climate researcher is to increase our understanding of the climate we experience. In climate science there is a history of researchers using data sets to identify statistical relationships between variables. The science challenge is to understand why there is a correlation and to use that information in a predictive sense.

3 A fundamental conundrum in meteorology is that we have good predictability for about 5 to maybe 7 days in the mid-latitudes. But beyond that not a lot of skill in forecasting – and what we do have is probably due to tropical forcing. Whereas, in the tropics, short term predictability is low. Forecasters rarely beat persistence on day time-scales unless there is a major synoptic event like a tropical cyclone. However, on longer timescales (of the order of a month and beyond), low, but positive skill is provided by a variety of tropical features.

4 Mid-latitude weather forecasts have reasonable accuracy out to a maximum of two weeks (currently somewhat less). Seasonal forecasts, on timescales of 1 month to 1 year have lower skill than weather forecasts and have higher skill in the tropics. Scenarios for climate change on timescales of greater than 1 year are informed by changing composition of the atmosphere – a feature that is reasonably well predicted. PREDICTABILITY Mid-latitudes Tropics Global

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9 The cutting-edge science questions this arrangement of the atmosphere (clouds, clear bits, moisture, thunderstorms, winds, etc) poses are: What are the time and space scales of organisation? Why are they like that? How can we represent these in models of the atmosphere? What do we have to measure to: (1) specify the significant parts of the atmosphere properly, and (2) how should we analyse these observations so that our predictive models can make best use of our observations?

10 Matt Wheeler’s answer is that the atmosphere (and the tropical bit in particular) is made up of a zoo of propagating waves.

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12 CHANGING LARGE-SCALE PATTERNS Over the period 1950 to 2003 there appears to have been a systematic change in temperature and rainfall Temperature anomaly

13 ANOTHER LARGE-SCALE FEATURE IS THE WALKER CIRCULATION The Walker Circulation – the schematic circulation between South America and Southeast Asia/North Australia

14 So, is the Walker Circulation responding to these changes in global temperature? It seems to me to be a cutting edge science question to answer this. An El Nino event is a weakening of the Walker Circulation, a La Nina event a strengthening. There are many systems, both statistical and dynamical that attempt to model, in a predictive sense, this Circulation. To succeed in modelling the Walker Circulation, so that we could predict its changes, would be a cutting- edge scientific achievement.

15 The Bureau of Meteorology operates the POAMA system, and using it routinely produces an ensemble of predictions for the strength of the Walker Circulation.

16 ENSO AND EXTREME EVENTS Average annual number of tropical cyclones in 2 o X 2 o grid boxes (1969 – 1998 climatology). In the La Nina years there are more tropical cyclones, and they are closer to the Australian coastline, than in the El Nino years.

17 The story of Australian climate, and particularly rainfall, is closely tied to what happens with the El Nino / La Nina cycle. RAINFALL AND ENSO El Nino La Nina

18 RAINFALL AND EL NINO THE EL NINO YEARS , , , , , , , , , , , , , , , , , El Ninos in the past 100 years, 11 to 1950 and 12 since. Composite pictures of the summer and winter rainfall anomalies for the twelve most significant El Ninos. summer winter

19 RAIN AND LA NINA THE LA NINA YEARS: , , , , , , , , , , , , , La Ninas in the past 100 years, 9 up to and including 1950, and 9 since. Composite pictures of the summer and winter rainfall anomalies for the twelve most significant La Ninas summer winter

20 SCENARIOS FOR RAIN AND TEMPERATURE The yellow ellipse encompasses 95% of the 1000 year unforced runs projections of temperature and precipitation for the Northern Australian region of the Canadian CGCM2 model. The blue ellipse is from the UK Hadley Centre HadCM3 model. About 1 o C warming and 15% more rainfall in the north in summer. Northern Australia extends from the north coast to 30 o S. Blue – HadCM3 Yellow - CGCM2 SUMMER - NORTH Source: Ruosteenoja, Carter, Jylha and Tuomenvirta, “ Future climate of world regions: an intercomparison of model- based projections for the new IPCC emission scenarios”. Pub: Finnish Environment Institute. Helsinki 2003.

21 SCENARIOS FOR RAIN AND TEMPERATURE About 1 o C warming and no change in rainfall in the north in winter. Blue – HadCM3 Yellow - CGCM2 WINTER - NORTH

22 SCENARIOS FOR RAIN AND TEMPERATURE Blue – HadCM3 Yellow - CGCM2 SUMMER - SOUTH About 1 o C warming and maybe slightly more rainfall in the south in summer.

23 SCENARIOS FOR RAIN AND TEMPERATURE Blue – HadCM3 Yellow - CGCM2 WINTER - SOUTH About 1 o C warming and no change in rainfall in the south in winter.

24 For broad scale scenarios to be truly useful they need to be down-scaled so as to inform private individuals, farmers, fishers and small- and large-business operators how climate, climate change and climate variability will affect them. Accurate, verifiable downscaling is cutting-edge science

25 After developing scenarios for climate change and downscaling these they must be extended to better understand impacts on biological and economic systems (most particularly on global trade and national energy policy). High quality Earth-system simulation is cutting-edge science

26 CLIMATE SERVICES Must be what the user community needs and wants

27 THE MOST POPULAR PRODUCTS

28 THE MOST POPULAR PRODUCTS #1

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30 THE MOST POPULAR PRODUCTS #2

31 THE MOST POPULAR PRODUCTS #3 Temperature Temperature anomaly

32 THE MOST POPULAR PRODUCTS #4 Other charts; eg NDVI and various seasonal timescale forecast products

33 WHAT ELSE ? Climate service users want: More data – radar, observations, predictions; Local scale information; Simple explanations or explanations of likely uncertainties; and Forecasts at the scale of their enterprise with long lead times and high accuracy.

34 THE FUTURE CUTTING EDGE SERVICE ? Cutting edge services will continue to make good use of the most up-to-date science to develop products and the best technologies to deliver these services. Cutting edge services will inevitably follow the delivery of cutting edge science The cutting-edge service will develop partnerships to form the link between scientists and users throughout the community. THANK YOU