Averages of pressure in the centres of cyclones and anticyclones in 5° lat./long. squares in the Australian Region in January and July have been computed for the twelve year period 1952-1963. The extreme minimum pressure in cyclonic centres and extreme maximum pressure in anticyclonic centres in each 5° square, in which a sufficient number of centres occurred, has also been charted. Resuits are represented by isopleths of the pressure averages, extreme minimum and extreme maximum pressure of centres. Although the relation between the changes in intensity of systems and their direction of motion has not been investigated specifically, it is felt that the charts might indicate areas where systems tend to intensify or to weaken. The charts should be considered as a first approximation to the climatologically reliable distribution. It is intended to prepare similar charts for all months of the year.
S. Karelsky (Sun,) studied this question.