Effects of vegetation models on urban CO2 simulations over the Greater Toronto Area

Urban areas are hotspots for CO₂ emissions. Therefore, accurately estimating sources and sinks in these areas is important for studying the urban carbon budget. Due to the heterogeneous land cover of urban areas, modeling in high resolution is essential for accurate estimates of CO₂ fluxes and concentrations in urban domains. Being a major sink for CO₂, the urban biosphere plays a crucial role in the urban carbon budget, and accurately estimating the biogenic fluxes is key to our understanding of the urban carbon cycle. We model CO₂ concentrations in the Greater Toronto Area (GTA), the largest metropolitan area in Canada, using the Weather Research and Forecasting Model coupled with GEOS-Chem (WRF-GC), which makes it possible for us to run high resolution simulations in our region of interest, with a resolution of 1 km x 1 km. For our biogenic fluxes, we use two regional biogenic models, the Solar Induced Fluorescence for Modelling Urban biogenic Fluxes (SMUrF) and the Urban Vegetation Photosynthesis and Respiration Model (UrbanVPRM), in addition to the global biogenic fluxes from the Más Informada Carnegie-Ames-Stanford-Approach (MiCASA) model, to assess the effects of different vegetation models on CO₂ concentrations over the GTA. Using the regional biogenic models with 500m x 500m resolution and global emissions with 0.1 x 0.1 degrees resolution, we investigate the effects of including different high resolution fluxes in our model, and how modifications in these vegetation models can affect the CO₂ concentrations around our model domain.