Eureka Station and Bruker FTS NDACC Metadata
PEARL FTS NDACC Rapid Delivery Data
PEARL FTS TCCON Data and Metadata

For more information about the PEARL FTS please contact Dr. Kimberly Strong

The PEARL FTS is a high-spectral-resolution IFS 125HR Fourier transform infrared (FTIR) spectrometer produced by Bruker Optics Inc, which was installed at the PEARL Ridge Lab in 2006 (Batchelor et al., 2009). A FTIR Spectrometer operates by splitting the incoming light (using a specialized optical beamsplitter) into two beams of different length. A changing path difference between the two beams is introduced by the use of a moving mirror in one beam. The constructive and destructive interference that results when the beams are recombined is measured by a detector. This resulting signal is called an interferogram. A mathematical transformation, the Fourier transform, of the interferogram produces a spectrum, which is essentially a ‘fingerprint’ of the atmosphere that the sunlight has passed through on its way to the instrument. Absorption features in the spectrum are produced by specific molecules in the atmosphere, providing information about the concentrations of these gases.

The PEARL FTS measures both tropospheric and stratospheric gases using solar infrared absorption spectroscopy. Sunlight enters the instrument by way of a custom-built Community Solar Tracker (CST) mounted inside of a mechanical dome on the roof and several mirrors inside the FTS lab (Franklin, 2015). The instrument records spectra at high resolution (typically 0.0035 cm−1, corresponding to a maximum optical path difference of 250 cm) in both the mid-infrared and near-infrared. Measurements are taken during clear-sky conditions in the sunlit part of the year (late February to late October), and if weather permits, approximately 70 spectra are recorded per day, cycling through a series of spectral filters. These spectra are analyzed using retrieval software to obtain column amounts of atmospheric constituents and some information about their vertical distributions (I.e. vertical atmospheric profiles). Constituents measured include reactive species, source gases and reservoirs that play a role in stratospheric ozone depletion; pollutants that are the by-product of biomass burning and anthropogenic activities such as combustion; greenhouse gases that contribute to global warming, and dynamical tracers that provide information about atmospheric transport processes. These data are also being used for validation of satellite measurements made by the Canadian Space Agency’s Atmospheric Chemistry Experiment, as well as the European Space Agency’s TROPOspheric Monitoring Instrument. The PEARL FTS is a certified instrument of the Network for Detection of Atmospheric Composition Change (NDACC) and was equipped to meet the requirements of the Total Column Carbon Observing Network (TCCON) in September 2009.