Abstract
Some resent works in Japan on the standardization of the measurement of total carbonate
(TCO2) arereviewed. Themeasurement method and thestandard areneeded to setconsistent and
traceable among each labs to keep uncertainties of the data within few μmol/kg in worldwide
scale. A experimental work to make a standard of total carbonate based on natural sea water is
introduced. The results of the time series measurement improves that the sea water standard
keeps its concentration ofTCO2 over 80 days with the variability of ± 1.4 μ mol/kg. Some ex
amples of the intercalibration works in Japanese labs show that there are complex and unique
systematic offsets between each lab’s data. Thus it is recommended that a consistent program of
the intercalibaration study for total carbonate is needed to put forward.
