Advances in Urban Greenhouse Gas Monitoring: Integrating Slow-Response Atmospheric Towers and Wavelet-Based Techniques for Flux Measurements and Attribution

Global surface temperatures continue to rise, with projections indicating over 2°C warming by 2100, primarily attributed to anthropogenic greenhouse gas emissions. Urban areas, responsible for 70% of global emissions, are focal points for climate change mitigation. The PAUL Cities project aims to monitor emissions reduction in megapoles. Current monitoring infrastructures like ICOS focus on atmospheric, oceanic, and ecosystem measurements. This study explores the potential of using slow-response analyzers on tall atmospheric towers for Eddy Covariance flux computations, addressing technical challenges and height-induced complexities. Additionally, a novel wavelet-based method is proposed for attributing fluxes to biogenic and anthropogenic sources, using carbon monoxide as a distinctive tracer. Results from sites near Paris demonstrate the feasibility and versatility of these approaches, offering valuable insights for urban emission monitoring strategies worldwide.