RAINFALL VARIABILITY IN CENTRAL WEST ARGENTINA AND A STATISTICAL FORECAST MODEL
Diana Analía Domnguez, Marcela Hebe Gonzalez
Departamento de Ciencias de la Atmósfera (FCEN-UBA), Buenos Aires, Argentina
Centro de Investigaciones del Mar y la Atmósfera (CIMA/CONICET-UBA), UMI IFAECI/CNRS, Buenos Aires, Argentina.
Manuscript received on 17 December 2012, in final form on 23 April 2013
The objective of this work is to study rainfall variability in different timescales in central Argentina. Rainfall trends were maximum in summer in the west of the study region, showing rainfall decrease in the west and recent period. 15, 23 and 30 years significant cycles were detected. The interannual summer rainfall variability was study in 3 sub-regions, based on the comparison of the atmospheric and oceanic variables behavior in years with deficit and excess of rainfall. The geopotential height was the best discriminator variable. Rainfall greater than normal was associated with the weakness of the Pacific heights and lows and the intensification of the Atlantic heights in the region next to the continent. The central Pacific Ocean water warming (positive phase of ENSO-El Niño Southern Oscillation) was another factor related to rainfall all over the area. A multiple linear regression model was developed and explained the 43,3% of the summer rainfall variance.