A Measurement Campaign in Thessaloniki, Greece, to Detect and Estimate Local Greenhouse Gas Emissions

The reduction of carbon emissions is required to limit global warming. Thus, measurement-based methods to monitor the progress in reducing emissions are essential. A significant part of the global emissions is produced in urban areas where also industry is located. Here, we investigate the urban area of Thessaloniki to better understand the distribution of local greenhouse gas sources during October 2021 and the summer of 2022.We present results of a measurement campaign using a pair of Fourier-Transform Infrared (FTIR) Spectrometers of the type EM27/SUN developed by Bruker and KIT.The measurement campaign took part in the framework of the Collaborative Carbon Column Observing Network (COCCON). During the campaign the spectrometers were used in an up- downwind setup. One spectrometer was located in a central position of the city while the second instrument was transported to various locations at the boundaries of the city, selected according to the prevailing wind direction. Additionally, measurements to characterize the advected background variability were performed. Here, the spectrometers were arranged orthogonal to the prevailing wind direction to estimate the variability of the background concentrations of carbon dioxide and methane.In total, 30 days of measurements were collected, giving a comprehensive dataset to study the emissions of the city area. The measurements are interpreted using a box model to estimate the averaged emission area fluxes. We present results for both, carbon dioxide and methane, and discuss the temporal and spatial variability we encountered.In a next step, we aim to confront these measurements with simulation results with idealized tracer emission patterns using the ICON-ART modeling framework, a numerical weather forecast model developed and used operationally by the German Weather Service (DWD). The results from the box model introduced above will be used as a starting point to combine measurements and simulations. First simulations produced for this purpose will be shown.