Measurement of Atmospheric CO₂ Column Concentrations Based on Open-Path TDLAS

Area of Science:

• Atmospheric science and remote sensing.
• Environmental monitoring and spectroscopy.

Background:

• Accurate monitoring of atmospheric carbon dioxide (CO2) column concentrations is crucial for climate research and understanding carbon cycles.
• Existing methods may have limitations in spatial coverage or deployment flexibility for comprehensive atmospheric monitoring.

Purpose of the Study:

• To develop and validate a mobile open-path system for measuring atmospheric CO2 column concentrations.
• To assess the system's feasibility for monitoring carbon emissions over extensive areas.

Main Methods:

• A tunable diode laser absorption spectroscopy (TDLAS) system was designed for mobile, open-path measurements.
• A 2 μm distributed feedback diode laser emitted a beam downwards, reflected by a ground-based retroreflector array.
• Measurements were conducted over 20 m and 110 m vertical paths, with comparisons to distributed single-point sensors.

Main Results:

• The TDLAS system achieved a minimum detection limit of 0.52 ppm for CO2 column concentrations.
• Observed trends from the open-path TDLAS system showed similarities with distributed single-point sensors.
• Average values from distributed sensors were more consistent with open-path TDLAS measurements than single-point data.

Conclusions:

• The developed mobile open-path TDLAS system is feasible for measuring atmospheric CO2 column concentrations.
• This technology demonstrates potential for effective monitoring of carbon emissions across large spatial scales.
• The findings support the use of open-path TDLAS as a valuable tool in atmospheric research and environmental monitoring.