Remote atmospheric sensing with an airborne laser absorption spectrometer

Area of Science:

• Atmospheric science
• Spectroscopy
• Remote sensing

Background:

• Accurate measurement of atmospheric constituents is crucial for understanding air quality and climate.
• Remote sensing techniques offer non-invasive methods for atmospheric profiling.
• Laser absorption spectroscopy provides high sensitivity for detecting trace gases.

Purpose of the Study:

• To develop and present a laser absorption spectrometer system for measuring altitude profiles of atmospheric constituents.
• To demonstrate the application of this technique for ozone, nitric oxide, and water vapor.
• To analyze the feasibility and limitations of the technique for remote atmospheric sensing.

Main Methods:

• Utilizing an infrared laser transmitter and a heterodyne radiometer for signal detection.
• Employing differential absorption measurements at multiple wavelengths.
• Leveraging the Earth's surface as a diffuse reflector for the return signal.
• Exploiting pressure broadening of absorption lines to differentiate between high and low altitude absorbers.

Main Results:

• The technique successfully measures altitude profiles of ozone, nitric oxide, and water vapor.
• Pressure broadening is shown to be effective in discriminating absorber altitudes.
• CO2 and CO lasers are identified as suitable transmitters for this application.

Conclusions:

• The developed laser absorption spectrometer is a viable tool for remote sensing of atmospheric pollutants.
• The technique offers potential for monitoring air quality and atmospheric composition from airborne and spaceborne platforms.
• Further research should focus on optimizing altitude resolution and addressing instrument stability.