Figure 1. Trends of annual mean CO₂ flux into the ocean from 1970 to 1995.

Ensemble mean of uninitialized simulations (a) and assimilation simulation (b) (units: gC m⁻² per year²). The trends are calculated based on linear regression. The dots show grid points where the trends are significant at 95% level, based on a two-sided t-test. The green box in a denotes the SPG region where the mid-1990s abrupt warming occurred¹¹, and the green box in b denotes the western SPG region where the CO₂ flux increases the most.