Presenter: Ariane Verdy (UCSD)

Description:
A new high-resolution version of the Tropical Pacific Ocean State Estimate (TPOSE) is used to investigate the dynamical processes controlling upper ocean temperature, salinity, carbon, and oxygen variability. TPOSE is a model-observations synthesis produced using the MITgcm and its adjoint model to assimilate temperature, salinity, and sea surface height data. It is coupled to a biogeochemical model that simulates oxygen, nutrients, chlorophyll, and the carbon system (including pH and pCO2). Enhancing the horizontal resolution to 1/6 degree and the vertical resolution to 2 m near the surface improves the simulation of features such as Tsuchiya jets and tropical instability waves (TIWs). Changes in upper ocean properties such as buoyancy frequency and velocity shear are linked to the diurnal cycle and the passage of TIWs. The signature of TIWs is also identified in biogeochemical tracers and is attributed to vertical and horizontal advection, mixing, air-sea gas exchange, and biological production and consumption by closing the tracer budgets.