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| When the sunspot and lunar cycles coincide there are distinct rainfall peaks. The 18.6 year Lunar cycle created flood years in Central Victoria in 1954-56, 1973-75, 1992-93 and 2010-11. The 2010-11 floods in northern Australia reflected a peak lunar rain-enhancement cycle. This particular lunar cycle was strongly enhanced by the closely synchronised 19.86 year Jupiter-Saturn Synodic Cycle. |
Kevin Long (Jul 7, 2011) - Planetary and lunar cycles play an important part in shaping the climate, and also Australia’s flood and drought cycles are influenced by these forces. The Central Victorian rainfall records reveal that the 18.6 year lunar declination cycle and the 19.86 year synodic cycle of Jupiter-Saturn can each enhance or diminish average rainfall over prolonged periods resulting in extreme flood and extreme drought cycles. When these two cycles are closely in-phase with each other and are supported by the El Nino or the La Nina cycle, extreme droughts and extreme floods are likely to occur. This was the case during the early months of 2011 and enhanced by a very strong La Nina cycle during the preceding 9 months. Another major drought period is scheduled to occur around the middle of this lunar cycle (2020).
The above graph shows the long-term rainfall record for Bendigo in Central Victoria, Australia. The Central Victorian climate is particularly sensitive to any changes in average air movements (air tides). This is due to the generally flat terrain of the area, which means the effects of the cosmic cycles are more prominent than in most other places in the world. This can be seen to occur with about 80% reliability during the last 66 years. The dominating effects are most obvious when a four-year rolling average line is used (thick line). The spacing of the recent droughts to flood periods appears to closely follow the “9.3 year rule” (i.e. half of the 18.6 year moon cycle). Peaks and troughs relative to the Bendigo’s long-term average of 544 mm are:
1944 Severe drought (284 mm)
1954-56 Typical three years of major floods (average 737 mm)
1967 Severe drought (278 mm)
1973-75 Wettest ever three year flood period (average 861 mm).
1982 Driest year on record (206mm)
1992-93 Two years of flood period (averaging 729 mm per year
2002 After 9 years of declining average rainfall, 2002 delivered only 271mm
2010 Eleven consecutive months of above-average rainfall set a new Bendigo record of 1061 mm.