Mechanisms driving ESM-based marine ecosystem predictive skill on the east African coast

Abstract

The extension of seasonal to interannual prediction of the physical climate system to include the marine ecosystem has a great potential to inform marine resource management strategies. Along the east coast of Africa, recent findings suggest that skillful Earth system model (ESM)-based chlorophyll predictions may enable anticipation of fisheries fluctuations. The mechanisms underlying skillful chlorophyll predictions, however, were not identified, eroding confidence in potential adaptive management steps. This study demonstrates that skillful chlorophyll predictions up to two years in advance arise from the successful simulation of westward-propagating off-equatorial Rossby waves in the Indian ocean. Upwelling associated with these waves supplies nutrients to the surface layer for the large coastal areas by generating north- and southward propagating waves at the east African coast. 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.

Attribution and Predictability of Climate‐Driven Variability in Global Ocean Color

“…In addition, rCHLa skill in the Southern Indian Ocean is also related to ENSO evolution (Figures 4a and 4b). Jeon et al (2022) demonstrated that wind stress forcing caused by ENSO to Indian Ocean teleconnections generates skillful chlorophyll prediction up to 2 years arise from off-equatorial Rossby waves and supplies nutrients in the Indian Ocean.…”