Application and evaluation of the WRF-chem modelling infrastructure over Ireland to support greenhouse gas mitigation policies

Managing greenhouse gas (GHG) emissions at a landscape scale requires a framework that can account for local and advected sources. TerrainAI is a funded project that is designed to provide the scientific infrastructure needed to make policy decisions at a national scale to mitigate net GHG emissions from the Irish landscape. The project has established new observation platforms over a variety of natural (e.g., grasslands, peatlands, and forests) and urbanised landscapes and uses satellite and drone technologies to capture detailed spatial and temporal data on the physical properties of land-cover. A core part of the work uses the Weather Research Forecasting (WRF) model coupled with chemistry (WRF-Chem) to simulate the net emissions and transport of GH gases. WRF-Chem has been set up for double nested domain with the entire country of Ireland as inner domain at 1 km resolution; a third nest will be established for the Dublin metropolitan area at a resolution of 250 m. The current model incorporates better resolved model input fields (e.g., land use, meteorology, and emissions) and is evaluated for two 15-day periods in 2018, representing a dry and wet periods dominated by anticyclonic and cyclonic activity respectively. The Dublin nest will employ detailed descriptions of the urban canopy layer and examine their influence on the net emission and dispersion of GHGs. Currently, a WRF-Greenhouse option is used to simulate CO₂, CO and CH₄ over the study region using the EDGAR emission inventory, which can capture hot-spots and general patterns. More precise emission and sequestration data based on socio-economic profiles will be generated to match the detailed land-cover database used in WRF. These data will permit us to evaluate the efficacy of mitigation policies.