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EVIDENCE FOR LUNI – SOLAR M n AND SOLAR CYCLE S c SIGNALS IN AUSTRALIAN RAINFALL DATA
Author(s) -
CURRIE ROBERT G.,
VINES ROBERT G.
Publication year - 1996
Publication title -
international journal of climatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.58
H-Index - 166
eISSN - 1097-0088
pISSN - 0899-8418
DOI - 10.1002/(sici)1097-0088(199611)16:11<1243::aid-joc85>3.0.co;2-e
Subject(s) - climatology , teleconnection , environmental science , geography , volcano , flood myth , varve , geology , el niño southern oscillation , seismology , paleontology , archaeology , sediment
Abstract Spectrum analysis of 308 yearly sampled Australian rainfall series yields evidence for two terms with periods 18·3 ± 1·8 and 10·5 ±0·7 years in 270 and 182 instances, respectively. The long‐period term is statistically significant at a confidence level of 99·9 per cent. They are identified as the 18·6‐year luni‐solar M n and 10–11‐year solar cycle S c signals previously reported in other climate data such as American and South African rainfall, tree‐rings world‐wide, rainfall indices, air temperature world‐wide, air pressure world‐wide, sea‐level world‐wide, river flow, American crop yields and livestock/poultry production, European fish catches and dates of wine harvest, varves, thunderstorm occurrence, Earth rotation, and volcanic eruptions. In eastern Australia, M n wave minima were in phase with epochs 1880·3 and 1898·9 (epochs are dates of maxima in tidal forcing). At mid‐epoch 1908·2, epoch 1917·5, and mid‐epoch 1926·8 virtually all luni‐solar wavetrains experienced a 180° change in phase. Thus, by 1936·1 virtually all the waves were out of phase with the epoch, a correlation that continued at epochs 1954·7 and 1973·3. An entirely analogous phenomenon occurred in USA rainfall data, but it occurred in the third quarter of our century. The contribution of the M n and S c signals to total variance in the raw data is on average 19 per cent. This is of course highly unrealistic—and when the power in the raw data from 8 to 2 years is filtered out prior to analysis, and the variance contribution of the signals to filtered data compared over a common frequency interval (periods 30 to 8 years), their variance contribution increases dramatically to a mean of 89 per cent. Currie carried out similar analyses for six sets of climate data comprising over 3200 records and found the mean variance contribution of signals to filtered data over a common bandwidth varied from 67 to 81 per cent. Thus, the spectrum of climate at decadal and duo‐ decadal periods is strongly ‘signal‐like’ rather than ‘noise‐ like’ as radically assumed by statisticians and mathematicians over the past 70 years, and as generally believed by meteorologists during the past two centuries.