Modulation of seasonal precipitation in Argentina by the South Pacific high

Abstract

The aim of this work is to quantify the influence of the position and intensity of the South Pacific High (SPH) over seasonal rainfall in Argentina. Some indices were defined to measure the position and intensity of the SPH, and they were correlated with seasonal precipitation to study the relationship between them. Results indicate that the intensity of the SPH affects precipitation mainly in northern Argentina during spring and in the southern region in autumn and winter. The latitudinal shift of the SPH has proved to have a relevant impact on precipitation in the northeast in summer and winter, and in some regions of southern and central Argentina during winter and spring. When studying the possibility to foresee precipitation behaviour with a one-month lag, these metrics were not able to predict precipitation effectively in the northwest. On the contrary, the SPH intensity showed significant lagged correlations with rainfall mainly in the northeast, central-east and south during spring and summer while the position of the SPH is mostly significantly correlated with summer and winter precipitation in the northeast and central Argentina. Results suggest that the situation of SPH can provide some rainfall predictability.