The Influence of South American Rainfall on Adjacent Continents and Ocean

Speaker: Siyu Zhao
Institution: UCLA AOS
Location: 7124A
Date: January 31, 2024
Time: 3:30 pm to 4:30 pm


Major rainfall centers play a central role in determining spatial and temporal patterns of climate variabilities on planetary and global scales. As such, the impacts of the largest global rainfall center over the tropical Indo-Western Pacific on global atmosphere and climate variability over land have been studied extensively. However, the impacts of the second largest global rainfall center over South America on the adjacent continents and ocean have received little attention and thus are largely unknown. South America is home to the world’s largest rainforest—the Amazon rainforest and one of the major monsoon systems of the Southern Hemisphere—the South American monsoon system (SAMS). Here, I will first show how southeastern South American rainfall, which characterizes the intraseasonal variability of SAMS, influences weather patterns over northwestern Africa and western Europe via cross-equatorial propagation of upper-tropospheric Rossby waves. Secondly, I will show how central Amazonia rainfall anomaly influences Atlantic Niño/Niña events via eastward-moving convectively coupled Kelvin waves. These findings illustrate that South American rainfall has the potential to exert interhemispheric and oceanic impacts.