Journal Article

Summer precipitation variability over South America on long and short intraseasonal timescales

Vera, Carolina Susana, Gonzalez, Paula Leticia Manuela

2014

Overview

A dipole pattern in convection between the South Atlantic convergence zone and the subtropical plains of southeastern South America characterizes summer intraseasonal variability over the region. The dipole pattern presents two main bands of temporal variability, with periods between 10 and 30 days, and 30 and 90 days; each influenced by different large-scale dynamical forcings. The dipole activity on the 30–90-day band is related to an eastward traveling wavenumber-1 structure in both OLR and circulation anomalies in the tropics, similar to that associated with the Madden–Julian oscillation. The dipole is also related to a teleconnection pattern extended along the South Pacific between Australia and South America. Conversely, the dipole activity on the 10–30-day band does not seem to be associated with tropical convection anomalies. The corresponding circulation anomalies exhibit, in the extratropics, the structure of Rossby-like wave trains, although their sources are not completely clear.

• Publisher: Springer,Springer-Verlag,Springer Berlin Heidelberg,Springer Nature B.V
• Subject: Australia / Climate models / Climatology / Climatology. Bioclimatology. Climate change / Convection / Earth and Environmental Science / Earth Sciences / Earth, ocean, space / Environmental aspects / Exact sciences and technology / External geophysics / Geophysics/Geodesy / Marine / Meteorological research / Meteorology / Methods / Oceanography / Precipitation / Precipitation variability / Seasons / South America / subtropics / Summer / temporal variation / Tropical environments / tropics / Water in the atmosphere (humidity, clouds, evaporation, precipitation) / Weather forecasting