Diurnal variability of δ¹³C and δ¹⁸O of atmospheric CO₂ in the urban atmosphere of Kraków, Poland

Abstract

This article presents the results of measurements of the isotopic composition and concentration of atmospheric carbon dioxide, performed on air samples from Kraków (Southern Poland) in different seasons of the year. A simple isotope mass balance model has been applied to determine the contributions of different sources of CO₂ to the urban atmosphere of Kraków city: the latitudinal/regional background, biospheric contributions and anthropogenic emissions. The calculations show that during the summer and early autumn the dominant contribution to local CO₂ peaks is the biosphere, making up to 20% of atmospheric CO₂ during the nocturnal temperature inversion in the lower troposphere. During early spring and winter, anthropogenic emissions are the main local source.

Keywords:

• Anthropogenic emission
• Carbon 13
• Carbon dioxide
• Global change
• Oxygen 18

Acknowledgements

The authors wish to thank Halina Mróz for carrying out the stable isotope composition measurements in Kraków, Martina Schmidt for carrying out the CO₂ concentration measurements, and Prof. K. Rózański for valuable discussions concerning the interpretation of the data and help during the writing of this article. The authors also wish to thank the Institute of Arctic and Alpine Research (INSTAAR) at the University of Colorado (CU), the National Oceanic and Atmospheric Administration (NOAA), Climate Monitoring and Diagnostics Laboratory (CMDL), Carbon Cycle Greenhouse Gases Group for providing their background CO₂ concentration and isotope composition data, the British Atmospheric Data Centre for the supply of their calculated back trajectory data and the European Centre for Medium Range Weather Forecasts who supplied the initial data via the BADC.

The measurements were partially financed by the Polish National Scientific Committee (project number: 11.11.220.01) and the Foundation for German-Polish Cooperation.