Calibration experiments based on a CO₂ absorption cell for the 1.57-µm spaceborne IPDA LIDAR

Area of Science:

• Atmospheric Science
• Remote Sensing
• Spectroscopy

Background:

• Accurate measurement of global atmospheric carbon dioxide (CO2) column concentrations is crucial for climate monitoring.
• Spaceborne Integrated Path Differential Absorption (IPDA) LIDAR systems offer high potential for such measurements.
• Laboratory calibration is essential for validating the performance of these sophisticated instruments.

Purpose of the Study:

• To calibrate a laboratory prototype of a spaceborne IPDA LIDAR system.
• To simulate and validate the measurement accuracy and stability of the IPDA LIDAR for atmospheric CO2.
• To assess the suitability of a custom CO2 absorption cell as a standard calibration device.

Main Methods:

• A customized CO2 absorption cell was used to simulate atmospheric CO2 column absorption.
• Calibration experiments were conducted on both the receiving system and the entire IPDA LIDAR system.
• Simulated atmospheric CO2 concentrations (400-415 ppm) were tested by varying the pressure within the absorption cell.

Main Results:

• The system demonstrated high accuracy with absolute errors consistently below 1 ppm.
• Standard deviations were low, with values less than 1.2 ppm for the IPDA LIDAR system (148-shot averaging).
• Allan deviation analysis confirmed long-term stability for both the receiving system and the IPDA LIDAR.

Conclusions:

• The laboratory calibration using a CO2 absorption cell successfully validated the high accuracy and stability of the spaceborne IPDA LIDAR prototype.
• The developed calibration method and the absorption cell show promise as a standard for atmospheric trace gas sounding research.
• The results confirm the potential of IPDA LIDAR for precise global CO2 monitoring.