Open-Path Fourier Transform Infrared Spectroscopy

The sections in this article are Introduction Historical Perspective Current State of the Art Principles of OP/FT-IR Monitoring Optics Transfer Optics Telescopes Retroreflectors IR Sources Detectors Monitoring Configurations Monostatic Configurations Bistatic Configurations Siting and Selection of Monitoring Paths Data Acquired Beer's Law Interferograms and Single-Beam Spectra Background Spectra Absorption Spectra Concepts of Path-Averaged and Path-Integrated Concentrations Instrumental Parameters Measurement Time Spectral Resolution Apodization and Zero Filling Atmospheric Effects Data Analysis Preparation of Field Spectra for Analysis Correcting Single-Beam Spectra for Stray Light or Ambient Radiation Baseline Correction Correcting Absorption Spectra for Wavenumber Shifts Generating Reference Spectra Analysis Methods Nonlinear Response Quality Control Issues Measurement of the Random Noise Relative Intensities in Single-Beam Spectra Time Series Plots Correlation Plots Statistics from Multivariate Analyses Estimation of Detection Limits Accuracy and Precision Measurement of Permanent Gases Short Cell Comparability Applications Future Directions