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A Prototype Interferometer in the High Arctic: Calibration, Installation, and Initial Measurements

The Extended-range Atmospheric Emitted Radiance Interferometer (E-AERI) is a moderate resolution (1 cm-1) Fourier transform infrared spectrometer for measuring the absolute downwelling infrared spectral radiance from the atmosphere between 400 and 3000 cm-1. The extended spectral range of the instrument permits monitoring of the 400-550 cm-1 (20-25 μm) region, where most of the infrared surface cooling currently occurs in the dry air of the Arctic. Spectra from the E-AERI have the potential to provide information about radiative balance, trace gases, and cloud properties in the Canadian high Arctic. The instrument was installed at the Polar Environment Atmospheric Research Laboratory (PEARL) Ridge Lab (610 m altitude) at Eureka, Nunavut, in October 2008. Measurements are taken every seven minutes year-round, including polar night when the solar-viewing spectrometers at PEARL are not operated. A similar instrument, the University of Idaho's Polar AERI (P-AERI), was installed at the Zero-altitude PEARL Auxiliary Laboratory (0PAL), 15 km away from PEARL, from March 2006 to June 2009. During the period of overlap, these two instruments provided calibrated radiance measurements from two altitudes. In this talk, I will discuss the E-AERI's calibration, installation, validation, radiance comparisons with the P-AERI, and initial total column trace gas retrievals.