Autonomous Year‐Round Measurements of O3 ${\mathbf{O}}_{\mathbf{3}}$, CO $\text{CO}$, CH4 ${\text{CH}}_{\mathbf{4}}$, and N2O ${\mathbf{N}}_{\mathbf{2}}\mathbf{O}$ in the High Arctic With the Atmospheric Emitted Radiance Interferometer

Abstract Despite its status as a proverbial canary in the coal mine for global climate change, the Arctic has limited observational data, particularly during polar night. Longwave atmospheric emission has been recorded since 2006 at the Polar Environment Atmospheric Research Laboratory, located at Eureka, Nunavut, Canada (80N). Profiles and total columns of ozone (), carbon monoxide (CO), methane (), and nitrous oxide () were retrieved from these measurements from 2008 to 2022, and the contribution of the water vapour continuum to the radiative transfer improved the spectral fitting. The mean relative difference between the Extended‐range Atmospheric Emitted Radiance Interferometer (E‐AERI) and those from co‐located instruments (Bruker 125HR, Triax‐180 UV‐VIS spectrometers, and ozonesondes) were reasonable: after smoothing with the E‐AERI averaging kernel, these differences are +15.8% for , −0.1% for , +7.1% for , and +0.8% for compared to the 125HR, and are +17.8% and +24.2% for compared to the GBSs and ozonesondes, respectively. Significant depletion and enhancement events as a result of polar vortex dynamics/chemistry and wildfires respectively were also observed in the E‐AERI time series, along with the diurnal cycle. Finally, trends of +0.31 0.17% , −0.75 0.14% , +0.94 0.09% , and +0.38 0.05% from 2011 to 2022 were found for , , , and total columns, respectively, generally consistent with previously reported global and regional trends.