El Ciclo de las Manchas Solares y la Precipitación en la Región del Eje Cafetero - Colombia

Abstract: In order to detect a possible influence of the solar activity cycle on the regional climate, it is established by correlations an inverse relation between the sunspots index and the annual precipitation in the following stations: Cenicaf\'e (1942-2014), Naranjal (1951-2014) , La Bella (1951-2014), Miguel Valencia (1953-2014), localized in the Region of the Eje Cafetero. This relation evidences a high statistical significance for the first three stations being higher with the sunspot index series delayed one and two years. The autocorrelations and the semivariograms calculated until 24 delays for the Cenicaf\'e, Naranjal and La Bella stations' series clearly show a cycle of 10 or 11 years for the first two stations. For La Bella station it is evident the cycle in the delays with inverse relation, delays 6 and 16. The frequency spectra of the Cenicaf\'e, Naranjal and La Bella stations' precipitations, obtained by the rapid Fourier transform, show contradictory results, while the Cenicaf\'e's frequency spectrum just denotes the cycle of 11 years, the Naranjal's frequency spectrum favors a cycle of 11 years, and La Bella frequency spectrum shows the strong presence of cycles of 11 and 22 years. A possible explanation for this apparent contradiction is exposed. Finally, to prove a coupling between regional precipitation and the 11-year cycle of solar activity, it is performed a statistical comparison between the precipitation average of the coincident years with the minimum values of the sunspot cycle and the precipitation average of the coincident years with the peaks of this cycle. This comparison evidences a high statistical significance for the Cenicaf\'e, Naranjal and La Bella stations' series. Demonstrating the influence of the sunspot cycle in the regional precipitations. This result is useful in the the long-term prevision of regional hydric availability.