Modeling ocean circulation and biogeochemical variability in the Gulf of Mexico

[摘要] A three-dimensional coupled physical-biogeochemical model is applied tosimulate and examine temporal and spatial variability of circulation andbiogeochemical cycling in the Gulf of Mexico (GoM). The model is driven byrealistic atmospheric forcing, open boundary conditions from a dataassimilative global ocean circulation model, and observed freshwater andterrestrial nitrogen input from major rivers. A 7 yr model hindcast(2004–2010) was performed, and validated against satellite observed seasurface height, surface chlorophyll, and in situ observations includingcoastal sea level, ocean temperature, salinity, and dissolved inorganicnitrogen (DIN) concentration. The model hindcast revealed clear seasonalityin DIN, phytoplankton and zooplankton distributions in the GoM. An empiricalorthogonal function analysis indicated a phase-locked pattern among DIN,phytoplankton and zooplankton concentrations. The GoM shelf nitrogen budgetwas also quantified, revealing that on an annual basis the DIN input islargely balanced by the removal through denitrification (an equivalent of~ 80% of DIN input) and offshore exports to the deep ocean(an equivalent of ~ 17% of DIN input).

[学科分类] 地球化学与岩石