Climate impacts on the structures of the North Pacific air-sea CO2 flux variability

[摘要] Some dominant spatial and temporal structures of the North Pacific air-seaCO₂ fluxes in response to the Pacific Decadal Oscillation (PDO) areidentified in three data products from three independent sources: anassimilated CO₂ flux product and two forward model solutions. Theinterannual variability of CO₂ flux is found to be an order ofmagnitude weaker compared to the seasonal cycle of CO₂ flux in theNorth Pacific. A statistical approach is employed to quantify thesignal-to-noise ratio in the reconstructed dataset to delineate therepresentativity errors. The dominant variability with a signal-to-noiseratio above one is identified and its correlations with PDO are examined. Atentative four-pole pattern in the North Pacific air-sea CO₂ fluxvariability linked to PDO emerges in which two positively correlated polesare oriented in the northwest and southeast directions and contrarily, thenegatively correlated poles are oriented in the northeast and southwestdirections. This pattern is identified in three products, providing CO₂and pCO₂. Its relations to the interannual El Niño-SouthernOscillation (ENSO) and lower-frequency PDO are separately identified. Acombined EOF analysis between air-sea CO₂ flux and key variablesrepresenting ocean-atmosphere interactions is carried out to elicit robustoscillations in the North Pacific CO₂ flux in response to the PDO. Theproposed spatial and temporal structures of the North Pacific CO₂fluxes are insightful since they separate the secular trends of the surfaceocean carbon from the interannual variability. The regional characterizationof the North Pacific in terms of PDO and CO₂ flux variability is alsoinstructive for determining the homogeneous oceanic domains for the RegionalCarbon Cycle and Assessment Processes (RECCAP).

[学科分类] 地球化学与岩石