On long-term changes in the correlation between Southern Hemisphere precipitation and variations in SOI and solar activity

TERESITA HEREDIA; ANA G. ELIAS

Praga

Congreso; 26th IUGG General Assembly (International Union of Geodesy and Geophysics); 2015

IUGG - IAGA - IAMAS

We evaluate changes in the correlations between precipitation and two possible forcings: the Southern Oscillation Index (SOI) and solar activity. Precipitation annual time series over Tucuman (26.85° S; 65.2° W) and Sidney (33.8° S, 151.2° E) for the period 1884-2010 were used. Running correlation between precipitation and forcing indices present significant values which vary from positive to negative according to the period considered. Due to the nature of the processes that lead to precipitation, the discernment between different forcing effects (SOI, solar, geomagnetic, anthropogenic and/or other ones), and the link between them and precipitation are highly complex and hard to detect. In a linear cause-effect mechanism, a stable correlation should be expected for the whole period. This is not shown by our results pointing at nonlinear effects and/or coupling processes between forcings.