Applying the adjoint method for biogeochemical modeling: Export of participate organic matter in the world ocean

摘要: The oceanic distributions of oxygen, dissolved nutrients and carbonare strongly affected by the production particulate material nearthe ocean surface its subsequent remineralization during sinkingor after deposition on sea-floor. Dissolved nutrient data canthus be used to derive rate constants biogeochemicalprocesses responsible for observed fields using inversemodeling. Here, a global circulation model is presented thatexploits existing large sets hydrographic, nutrientand carbon determines rates export andvertical particle fluxes that are compatible with concentrationdata. fitted property concentration bysystematically varying circulation, air-sea fluxes, andremineralization simultaneously. adjoint method appliedas an efficient tool iterative optimization procedure andproduces simulated in very good agreementwith measurements. globally integrated flux ofparticulate organic matter necessary realistic reproductionof observations significantly larger than exportestimates derived from primary productivity maps. Discrepancies arelargest oligotrophic, open-ocean areas, where exportfluxes up factor 6 higher values based primaryproductivity estimates Berger [1989]. This modelresult line recent investigation subtropicalNorth Pacific also revealed high fluxes. Modelexport much closer agreement estimatesbased satellite pigment most regions except theSouthern Ocean, seem tounderestimate significantly.