For more information about the E-AERI please contact Dr. Kimberly Strong

The Extended-range Atmospheric Emitted Range Interferometer (E-AERI) consists of a Fourier transform spectrometer with a spectral range of 400 – 3000 cm-1 and at a resolution of 1 cm-1. It measures the infrared thermal emission of the atmosphere where the spectral range importantly covers the so-called dirty window (approximately 400 – 600 cm-1, or 20 μm), where most of the infrared cooling occurs in the dry Arctic air. One measurement cycle includes a sky measurement as well as calibration measurements of two internal blackbodies to ensure accurately calibrated spectra.  Measurements are independent of sun or moon-light and are only interrupted during precipitation events (or maintenance) to prevent damage of the optics. The thermal emitted radiance is primarily dependent on the water vapour content and temperature of the atmosphere, allowing temperature and humidity profiles of the planetary boundary layer to be derived from the spectra.

Due to climate change, the water vapour content of the Arctic atmosphere is expected to increase, resulting in a change of the observed radiative transfer that can be derived through the E-AERI data. In addition, total columns of trace gases such as N2O, CH4, HNO3 and O3 can be retrieved from the spectra, providing year-round measurements and filling in a data gap present in the solar-viewing instruments located at PEARL. The dependence of E-AERI spectra on the infrared emission from atmospheric water content also allows for the study of clouds, particularly in the microphysical regime. This is an important area of study as these microphysical cloud properties are a heavy influence on cloud radiative interactions, which are a key source of uncertainty in current climate models.