Interannual Rainfall Variability over the South American Altiplano

Abstract

Summertime (December-February) precipitation is virtually the only water resource over the South American Altiplano, a semiarid, high-level plateau entrenched in the central Andes. On the interannual timescale, Altiplano rainfall exhibits pronounced fluctuations between drought and very wet conditions, with subsequent impacts on agriculture and hydrology. In this work, the large-scale patterns of convective cloudiness and circulation associated with interannual variability of the summer rainfall over this region are investigated using a regression analysis between relevant atmospheric fields (NCEP-NCAR reanalysis, outgoing longwave radiation) and an index of convection over the Altiplano.