PDO-ENSO Effects on Southern Brazilian Precipitation

The role of the Pacific decadal oscillation (PDO) was investigated in terms of the anomalous precipitation in southern Brazil related to the El Niño-Southern Oscillation (ENSO) using a long-term data set from 1961 to 2016 from 106-gauge stations. In addition, a direct comparison analysis was performed between El Niño plus positive PDO events and La Niña plus adverse PDO events to discover any modulating effects of PDO on precipitation. Our findings suggest that significant monthly favorable anomalous precipitation occurred in the entire region only during intense or extreme El Niño events, with no modulation effect from the PDO regardless of its intensity. However, monthly negative precipitation anomalies varied from small to medium at higher latitudes during robust La Niña periods, with some connection to adverse PDO events.