Synoptic-to-Regional-Scale Analysis of Rainfall in the Atacama Desert (18°–26°S) Using a Long-Term Simulation with WRF

Abstract In this study, reanalysis data and a long-term simulation with the regional climate model WRF (1982–2017; 10 km resolution) is used to analyze synoptic processes associated rainfall events in Atacama Desert. Five composites, each WRF-simulated events, are studied. They selected based on clustering comprise top winter South (23°–26°S), Southeast Atacama, North (18°–23°S), summer Northeast Atacama. Winter mostly strong low pressure systems over southeast Pacific atmospheric rivers at their foreside, while cutoff lows occurring anomalously far north facilitate Accordingly, tropical continental areas remote subtropical identified as primary moisture sources, transport toward Desert mainly takes place free troposphere (above 800 hPa). Strong southward displaced Bolivian high. During high shifted westward when compared events. Consequently, northern Chile located periphery of resulting easterlies may push convective from Altiplano, coast. Detailed analyses individual reveal that most important patterns not only control synoptic-scale into Desert, but also decisively influence circulation.