Jeudi 12 mai - Multi-year prediction of Marine Productivity in the Tropical Pacific
May 12, 2016
from 11:00 AM to 12:00 PM
Roland Séférian, CNRM-GAME
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Titre : Multi-year prediction of Marine Productivity in the Tropical Pacific
An estimated ~ 45 Pg of carbon are fixed every year by phytoplankton, the first level of the marine food web. This net primary production (NPP) sustains a large array of marine species across the trophic chain. In certain regions, e.g. the tropical Pacific, NPP exhibits fluctuations at inter-annual to decadal time scales. The predictions of NPP fluctuations could be of major relevance to the science-based management of marine resources. At present, the predictive capacity is hampered by the ability of Earth system models to reproduce the phasing and the amplitude of NPP variations. Here, we use observed sea surface temperature as a simple approach to partly overcome this difficulty. We present the first retrospective prediction of NPP over the last decades (i.e., from 1997 to 2010) with an Earth system model. Our findings suggest that NPP, which is predicted 3 years in advance over the tropical Pacific, exhibits higher predictive skill than physical ocean’s fields. Predictability arises from poleward advection of surface nutrients and iron that imprint fluctuations of ocean productivity over years.