Changes of Carbon Isotopes in Atmospheric CO2 of the Krakow Region in the Last Five Years

Abstract

The Krakow Radiocarbon Laboratory has been measuring isotope composition of atmospheric CO2 and its natural concentration in the Kraków region for the last five years. We have been sampling on a continuous basis in two-week intervals at ca 20m above ground level, close to the center of Kraków. CO2 was sorbed while slow pumping atmospheric air through a molecular sieve. After recovery by heating, the CO2 was converted to benzene and 14C measured in a liquid scintillation spectrometer. In a small portion of CO2 delta-13C was determined in a mass spectrometer. Concentration of CO2 was assessed by measurement of the volumes of the sorbed CO2 and the pumped air. A five-year record (1983-1987) reveals a multiannual linear trend and winter-summer oscillations. Calculated parameters of the regression line (intercept and slope) for the measured delta-14C, delta-13C and concentration are: 222 per mil (Jan 1983) and -15.5 per mil/yr, -9.57 per mil (Jan 1983) and -0.042 per mil/yr, 336ppm (Jan 1983) and 1.4ppm/yr, respectively.