Читать книгу Geophysical Monitoring for Geologic Carbon Storage - Группа авторов - Страница 43

Passive absorption spectroscopy is perhaps the simplest approach to measuring CO₂ where the Sun is the light source (Lindenmaier et al., 2014). A Fourier Transform Infrared (FTIR) spectrometer can be used to record the CO₂ spectrum for the atmospheric column. The instrumentation required for this approach tends to be simpler than other techniques discussed later because it does not require the use of a laser or other light sources that need to remain optically stable in the field. However, passive absorption spectroscopy has several limitations that limit utility as a method of monitoring CO₂ seepage to the surface. First, passive spectroscopy depends on the Sun and, therefore, cannot be used at night. The technique is also limited to looking in the direction of the Sun and is a column average that is well beyond the region above the sequestration reservoir. FTIR spectrometers can be used to measure the carbon isotopes of CO₂ but the fundamental physics of this approach requires a large instrument footprint.