High-resolution simulation of CO2 dispersion in urban atmosphere of Krakow, Southern Poland

Effective mitigation efforts in the face of observed climate change require independent tools based on atmospheric observations to estimate greenhouse gas emissions at different spatial and temporal scales. Atmospheric transport models constitute a key element of anthropogenic emissions monitoring and verification systems. It represents atmospheric transport in such systems, which allows the use of inverse methodology to estimate emissions from observed concentrations. Reliable numerical simulations of atmospheric transport over complex urban areas require model configurations that provide adequate resolution reflecting the complex topography and land cover, as well as parameterization of physical processes optimised for the specifics of urban areas. This study presents an attempt to apply the WRF-CHEM model for the simulation of CO2 transport in the urban area of Krakow, the second largest city located in the southern part of Poland. The simulation has been performed for a 3 day period in October 2021 and was validated by a CO2 molar fraction vertical measurements performed on board of a tethered balloon operating as a commercial touristic attraction in the city centre. The modelling results have been compared with the observations to determine model performance in terms of: (i) capture the temporal dynamics of the nocturnal boundary layer formation and (ii) identifying detected CO2 plume originating from a point source to confirm the expected source position and estimate the CO2 emission from that source.

The presented work was funded by the CoCO2 project, which has received funding from the European Union's Horizon 2020 research and innovation program under Grant Agreement No. 958927 and the "Excellence Initiative - Research University" program at AGH University of Science and Technology.