Extended Data Fig. 6: Trends and per cent changes in global mean N2 vertical sampling errors from 1960 to 2018 for three interpolation methods.
From: Increasing ocean stratification over the past half-century
a, Linear trends of N2 bias at each depth from surface to 2000m with an interval of 20 m at upper 500 m (100 m below 500 m) (same as Fig. 2a); b is same as a but for percentages of long-term changes relative to the 1981–2010 average of global mean N2. Three interpolation methods are included: Reiniger-Ross, Spline, and Linear interpolation. The dotted lines denote the observed N2 estimates. The shadings are 90% confidence intervals from 5000 realizations.
