Extended Data Fig. 5: The long-term trends of sea surface sAlk, sDIC, Salinity, and Revelle Factor in the Canada Basin.
From: Sea-ice loss amplifies summertime decadal CO2 increase in the western Arctic Ocean
The discrete samples of sea surface (depth < 20 m) Alk and DIC were obtained from the Global Data Analysis Project version 2 database38 (grey dots). We calculated salinity normalized DIC (sDIC = DIC×S0/SSS) and Alk (sAlk = Alk×S0/SSS) and then averaged the data to calculate monthly means (black dots) for the linear regressions (a and b). The S0 is the reference salinity, i.e. the long-term mean of SSS. We also conducted a non-zero endmember salinity normalization39 for DIC and Alk (d and e; see Methods). The corresponding Revelle Factor was calculated in the CO2SYS program (c and f). The underway measurement of salinity was used for examining the long-term trend (g). We tested whether the slope significantly different from 0 by ANOVA. The rates of change with standard error are shown.
