Evaluating Model Concentrations of Short-Lived Climate Forcers, as Used in the Arctic Monitoring and Assessment Programme, with Ground-Based Fourier Transform Infrared Spectroscopy
Résumé
The Arctic Monitoring and Assessment Programme (AMAP) is an Arctic Council Working Group focused on studying the Arctic environment and the impacts of climate change, providing detailed reports to inform policy development. Previous AMAP reports analysed the impacts of black carbon, tropospheric O3 and CH4 on the Arctic. The 2021 AMAP report is focused on the impact of Short-Lived Climate Forcers (SLCFs) on the Arctic climate, atmospheric chemistry, and human health. SLCFs are gases and aerosols that influence Earth’s radiative budget, with lifetimes shorter than that of CO2. Advantageously, working towards mitigation on these timescales may enable expedited climatological and radiative impacts. The work presented here evaluates the modeled concentrations of O3, NO, NO2, CH4, and CO from eleven AMAP models: CESM, CMAM, DEHM, EMEP-MSC-W, GEM-MACH, GEOS-Chem, MATCH, MATCH-SALSA, MRI-ESM2, UKESM1 and WRF-Chem. The modelled mixing ratios are output at three-hour intervals for the years 2008, 2009, 2014 and 2015, on model-defined grid spacing and pressure levels. These outputs are assessed against corresponding trace gas measurements from ground-based Fourier Transform Infrared (FTIR) spectrometers. The FTIR instruments used in this analysis are at the University of Toronto Atmospheric Observatory, in Toronto, Ontario (43.66ºN, 79.40ºW) and the Polar Environment Atmospheric Research Laboratory, in Eureka, Nunavut (80.05ºN, 86.42ºW). These sites have been operating since 2001 and 2006, respectively, as part of the Network for the Detection of Atmospheric Change (NDACC) Infrared Working Group. The objective of these comparisons is to assess how well the models reflect the measured state of seasonal cycles in total columns, and when applicable, in partial columns. Given the scarcity of Arctic-based research stations, the PEARL FTIR provides a valuable long-term trace gas dataset for model evaluation, which has not yet been utilized by the AMAP SLCF expert group.