Phase coherence between precipitation in South America and Rossby waves

Author(s)

Gelbrecht, Maximilian ^{[1, 2]} ; Boers, Niklas ^{[2, 3]} ; Kurths, Juergen ^{[1, 2, 4]}

Affiliation

^[1] Humboldt Univ, Dept Phys, Berlin - Germany

^[2] Potsdam Inst Climate Impact Res, Potsdam - Germany

^[3] Imperial Coll London, Grantham Inst, London - England

^[4] RAS, Inst Appl Phys, Nizhnii Novgorod - Russia

• Document type: Journal article
• Source: SCIENCE ADVANCES; v. 4, n. 12 DEC 2018.
• Web of Science Citations: 0

Abstract

The dominant mode of intraseasonal precipitation variability during the South American monsoon is the so-called precipitation dipole between the South Atlantic convergence zone (SACZ) and southeastern South America (SESA). It affects highly populated areas that are of substantial importance for the regional food supplies. Previous studies using principal components analysis or complex networks were able to describe and characterize this variability pattern, but crucial questions regarding the responsible physical mechanism remain open. Here, we use phase synchronization techniques to study the relation between precipitation in the SACZ and SESA on the one hand and southern hemisphere Rossby wave trains on the other hand. In combination with a conceptual model, this approach demonstrates that the dipolar precipitation pattern is caused by the southern hemisphere Rossby waves. Our results thus show that Rossby waves are the main driver of the monsoon season variability in South America, a finding that has important implications for synoptic-scale weather forecasts. (AU)

• FAPESP's process: 15/50122-0 - Dynamic phenomena in complex networks: basics and applications
• Grantee: Elbert Einstein Nehrer Macau
• Support Opportunities: Research Projects - Thematic Grants