661 / 2024-09-18 20:45:35
Quadruple Enhancement of Surface Chlorophyll Growth by Submesocale Fronts of Oceanic Eddies
Oceanic submesoscale processes,submesoscale fronts,ocean biogeochemistry,chlorophyll growth
Session 46 - Oceanic Mesoscale and Submesoscale Processes: Characteristics, Dynamics & Parameterizations
Abstract Accepted
Submesoscale fronts have been recognized as important contributors to nutrient supply for primary production in the euphotic layer. Their small spatio-temporal scale (100-101 km, 100-101 days) has hindered the understanding of their spatial structures, temporal evolution and biogeochemical impact. Here, by combining the global multi-platformed observations, we find that the submesoscale fronts around oceanic eddies are featured by an along-front enhancement of ageostrophic kinetic energy. Stronger fronts increase fourfold the surface chlorophyll growth rate on the warm side of the fronts, where the upwelling branch of a vertical secondary circulation emerges. The temporal evolution of submesoscale fronts of oceanic eddies is characterized by a frontal intensity peak with a lifecycle about 10 days. The frontal processes induce biogeochemical impact on a larger scale, which exhibits a net enhancement of surface chlorophyll of the corresponding eddies during this lifecycle, and the strongest enhancement of surface chlorophyll emerges when the frontal intensity reaches its maximum.