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Radiance and Trace Gas Measurements in Canada’s Harshest Environment

Spectra from the Extended-range Atmospheric Emitted Radiance Interferometer (E-AERI) provide information about the radiative balance and budgets of trace gases in the Canadian high Arctic. The instrument is a moderate resolution (1 cm -1 ) Fourier transform infrared spectrometer that measures the absolute downwelling infrared radiance from the atmosphere. It was installed at the Polar Environment Atmospheric Research Laboratory (PEARL) at Eureka, Nunavut, in October 2008 where its measurements were first used to study the impact of clouds and ice crystals on the radiative budget at two altitudes. Total columns of O 3 , CO, CH 4 and N 2 O have been retrieved year-round using a new retrieval algorithm and are in good agreement with measurements from other ground-based spectrometers at Eureka. The seasonal and diurnal variability of these gases have been determined using E-AERI measurements, which are taken every seven minutes year-round, including polar night when the solar-viewing spectrometers at PEARL are not operated. This allows E-AERI trace gas measurements to fill a gap in the PEARL dataset during polar night. In this talk, I will discuss the E-AERI’s instrumentation and measurements of radiative forcing from clouds and trace gases.