Mapping the locations of asymmetric and symmetric discharge responses in global rivers to the two types of El Niño

Abstract

River discharge variations play a pivotal role in global water and biogeochemical cycles and can impact the world’s agro-economics. Here, variations associated with the Central Pacific and Eastern Pacific types of El Niño are contrasted for thirty of the world’s largest rivers. Maps are constructed to identify the rivers that produce opposite-sign (i.e., asymmetric response (AR)) or same-sign (i.e., symmetric response (SR)) variations to these two types of El Niño. The mapping shows that the strongest AR occurs in North American rivers whereas the strongest SR occurs in the Murray River in Eastern Australia and the Danube River in Central Europe. Rivers in Asia and Africa vary in their response patterns depending on the phase (developing, mature or decaying) of El Niño. The response patterns are linked to precipitation variations within the river basins. The mapping presented offers an overview of which rivers may need new projection techniques and management strategies in response to the changes in El Niño type during recent decades.