Future changes in atmospheric synoptic variability slow down ocean circulation and decrease primary productivity in the tropical Pacific Ocean

Abstract

This study investigates the impact of future changes in atmospheric synoptic variability (ASV) on ocean properties and biogeochemical cycles in the tropical Pacific Ocean using coupled and forced atmosphere–ocean model experiments. Future climate projections show an annual mean decrease in ASV in subtropical gyres and an increase in the tropical band. Maintaining ASV to current values lead to a deepening of the mixed layer in subtropical regions and a shalllowing at the equator associated with a sea surface temperature decrease. The changes in ASV impact the large-scale ocean circulation and the strength of the subtropical and tropical cells, which constrain the equatorial water upwelling and the tropical net primary productivity. Ultimately, this study highlights the significance of ASV in understanding the impacts of climate change on ocean dynamics and biogeochemical processes, as half of the primary productivity decline due to climate change is caused by changes of ASV in the tropical Pacific Ocean.