[ACG59-03] Variability of dissolved inorganic carbon in surface seawater along the 165°E line and 137°E line.
Keywords:165°E line, 137°E line, Dissolved inorganic carbon, Growth rate
Based on the data of partial pressure of CO2 in seawater (pCO2sea) along the 165°E, Tanizaki et al. (JpGU2019) determined the growth rates of DIC from subarctic to equatorial zone by means of a multiple regression analysis using sea surface temperature as an explanatory variable. In this study, we used pCO2sea data taken by Japan Meteorological Agency (JMA) and the latest version of surface ocean CO2 atlas (SOCAT v2019), and calculated DIC growth rates along the 165°E line in the same manner as above. In addition, we compared those with DIC growth rates along the 137°E line to investigate the characteristic of DIC variability at each latitude.
We found that DIC growth rates along the 165°E line and 137°E line from 1996 to 2018 were almost comparable in regard to the meridional distribution which indicates larger in the northern zone and significantly smaller than those expected from atmospheric CO2 increases around 10°N.
However, there were some differences between them that DIC growth rate at 33°N along 165°E is significantly larger than that expected from atmospheric CO2 increase and that along 137°E as well as the uncertainties of DIC growth rates at 25° – 30°N estimated from multiple regression analysis were greater than those along 137°E and in the surrounding zone along 165°E.