ESM-based marine ecosystem prediction in large marine ecosystems of the Indian ocean

Abstract:

The extension of seasonal to interannual prediction of physical climate systems to that of marine ecosystem has a great potential to inform marine resource management strategies. A recent study showed that a global Earth system model (ESM) can skillfully predict marine biogeochemical variables averaged over large ocean basins, demonstrating the feasibility and application of ESM-based biogeochemical forecast systems. In this study, we further show that successful chlorophyll prediction skill against satellite observations is possible even in large coastal areas. By focusing on the Agulhas and Somali Coastal LME (Large Marine Ecosystem) regions, we find significant prediction skill almost up to 2-year lead time. The underlying mechanisms involved in this chlorophyll prediction skill in both LMEs are associated with the westward‐propagating oceanic Rossby wave. This upwelling wave supplies nutrients to the surface layer in both LME regions by generating north- and southward propagating waves at the western boundary. Further analysis shows that the off-equatorial Rossby wave is initially excited by wind stress forcing caused by El Niño/Southern Oscillation (ENSO)-Indian Ocean teleconnections.