Daily rainfall at Hobart has been related to M.S. L. geostrophic wind direction. For rainfall amount, both westerly and southeasterly winds are important. “Easterly rain” is less frequent than “westerly rain” and more variable, but the average falls are about the same. Easterly rain is the result of an east coast depression. The implications of O’Mahony‘s (1961) spectral analysis of Hobart‘s March and June rainfall are examined. Other stations in Tasmania, even those on the north and west side, show the same seven year quasi-period in June, although to a less pronounced degree than Hobart, suggesting a primary mechanism of high level disturbances. The phase of the seven year regularity in April is opposite to that in March and June, and it is absent in May. Thus there is no coherence of the phenomenon over the autumn season.
TROUP et al. (Wed,) studied this question.