Research (continued)

The working up of the results of the exercise took some time. The project was a fascinating example of how engineers are faced with problems similar to meteorologists. Much investigation and research was required to determine the optimum method of updating the telecommunications links between centres of population in Australia. It is interesting to recall that in the early 1940s Cornish and Squires had discussions with Boswell of the PMG on the problem of atmospheric refraction of short radio waves. They were aware that like optical refraction, the bending of radio waves was a meteorological phenomenon.

Meteorological Study No 1 reviewed the formulae describing the dependence of refraction on the vertical profiles of temperature and humidity and discussed similar optical effects. The report gives examples of profiles of refractive index calculated from individual radiosonde ascents at Darwin, Alice Springs, Hobart and Garbutt which gave a general indication of some Australian conditions.

Conclusions of the report were:

1. the radius of curvature of quasi-horizontal rays in the lower atmosphere in Australia is likely to vary between twice to six times the Earth's radius;


2. super-refraction was likely to occur with continental air blowing over a cooler sea, with subsidence inversions and with low level inversions in the early morning; and


3. the height of the super-refractive layer with early morning low level inversions will depend on the wind strength above the inversion.

One special investigation of particular interest was H. E. (Herbie) Whittingham's study of the long-range forecasting method of Inigo Jones. A disciple of Clement Wragge in the early 1900s, Jones developed a method of long-range forecasting based on the notion that a number of cycles were apparent in rainfall records which enabled forecasts to be made for some years ahead. Along with other private forecasters, most of whom had a special interest in weather, he had a clientele which, in the absence of long-range forecasts from the Bureau, needed his advice. Australia's climate, like that of other countries having arid and marginal lands, produces rainfall fluctuations which the poet Dorothea MacKellar memorably described as "droughts and flooding rains".

Many Australian farmers are haunted by the prospect of droughts and floods and many subscribed to Inigo Jones' long-range forecasting service as an aid to decision making on which crops to plant, and when.

Bureau of Meteorology