资源环境科技发展态势分析平台

Relatively rapid reemergence of anthropogenic carbon (C-ant) in the Equatorial Pacific is of potential importance for its impact on the carbonate buffering capacity of surface seawater and thereby impeding the ocean's ability to further absorb C-ant from the atmosphere. We explore the mechanisms sustaining C-ant reemergence (upwelling) from the thermocline to surface layers by applying water mass transformation diagnostics to a global ocean/sea ice/biogeochemistry model. We find that the upwelling rate of C-ant (0.4 PgC yr(-1)) from the thermocline to the surface layer is almost twice as large as air-sea C-ant fluxes (0.203 PgC yr(-1)). The upwelling of C-ant from the thermocline to the surface layer can be understood as a two-step process: The first being due to diapycnal diffusive transformation fluxes and the second due to surface buoyancy fluxes. We also find that this reemergence of C-ant decreases dramatically during the 1982/1983 and 1997/1998 El Nino events.