||Federation and Meteorology
Table of Contents
Memories of the Bureau, 1946 to 1962
Chapter 1: The Warren Years, 1946 to 1950
Chapter 2: International Meteorology
Chapter 3: The Timcke Years, 1950 to 1955
Chapter 4: A Year at the Massachusetts Institute of Technology
Melbourne to Cambridge, Massachusetts
Dynamic Meteorology I, II, III
Dynamic Meteorology IV
Audrey Joins Me in Boston
Was it Worthwhile?
Chapter 5: The Dwyer Years, 1955 to 1962
Chapter 6: A Springboard for the Future
Appendix 1: References
Appendix 2: Reports, Papers, Manuscripts
Appendix 3: Milestones
Appendix 4: Acknowledgements
Appendix 5: Summary by H. N. Warren of the Operation of the Meteorological Section of Allied Air Headquarters, Brisbane, 194245
Long-range Forecasting (continued)He would have been aware of the work of Charney and von Neumann at that time but probably did not dream that within twenty years NWP would have produced a remarkable advance in short-period forecasting. Charney (1951) had reported the result of a 24 hour numerical prediction of the 500 mb pattern over North America for 30 January 1949 using the Electronic Numerical Integrator and Computer (ENIAC) at the US Army Proving Ground, Aberdeen, Maryland.
Willet referred us to a useful article on climate change by C. E. P. Brooks (1951) in the Compendium of Meteorology. This gave a comprehensive review of geological and historical evidence of climate change and suggested causes for the changes which had occurred. The article contains 36 references to papers on the subject including that of Milankovitch in the Handbook of Climatology of Koppen and Geiger 1930.
Willet's reticence in assessing the progress made in long-range forecasting was useful in increasing my understanding of climate. He indicated that without a knowledge of the processes which produce fluctuations of weather, and fluctuations within climate, on time scales from days to years to centuries, millennia and further, there was little hope of improvement in short-range or long-range forecasting.
I have suggested that the use of random numbers to create a synthetic meteorological time-series in which apparent trends and cycles will appear can serve as a warning against impulsive conclusions when such trends and cycles appear in a natural time series. Synthetic time series of precipitation using random numbers could produce models containing an apparent advance and retreat of glaciers and the filling and drying-out of inland lakes. This would suggest that these changes may result from fluctuations within climate rather than from climate change.
Synoptic MeteorologyThe lectures of J. M. Austin on synoptic meteorology were interesting, but although they were far more comprehensive than those I had had in the Bureau's Training School in 1940 there was little that I had not already read in textbooks and articles in meteorological journals. This is in no way a criticism of Austin's lecturing style or his attitude to his students.
There was considerable emphasis on the basic processes involved in the development and movement of fronts and pressure systems with discussions on heating and cooling of the atmosphere, dynamics, geostrophic and gradient winds, horizontal divergence and vertical motion. Weather forecasting was mentioned with emphasis on the factors influencing air temperature, wind, precipitation, visibility, cloudiness and particularly cloud ceiling and fog.
After my Australian experience in the application of frontal theory, which appeared to still be an important part of synoptic analysis and prediction in North America, I asked Austin whether the Scandinavian frontal model was relevant in the North American and North Atlantic region. My lecture notebook records that he replied that examples appeared "every now and again".
One aspect of his lectures that I found particularly interesting was his discussion of streamlines and trajectories. This emphasised the dangers in making assumptions that both were similar, particularly when pressure gradients were weak and pressure systems moved quickly.
When I plotted some trajectories associated with moving anticyclones in Australian latitudes I realised that, in many cases, it would be difficult for the classical frontal model to be applied. This conclusion had been reached by Kidson (1947) and Palmer (1942) for the Southern Ocean and for southern areas of Australia although the observational data they used was very scanty. Palmer postulated that most fronts over southern Australia were occluded, which seemed reasonable as many zones of cloud were observed at middle and high levels.
It seemed that great care needed to be taken in applying the term 'front' to any zone delineating a change in wind direction or a zone of cloud or precipitation. The possibility that classical warm and cold fronts were likely to occur in southern Australia 'every now and again' seemed worth remembering but it seemed desirable to use different designations for the other significant wind changes, cloud lines, etc. In CAO we had learnt that fronts of the classical type were likely to be found in the vicinity of Southern Ocean oceanic convergence, especially in the Heard Island region.
Organisations in Australian Science at Work - Central Analysis Office (CAO)
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