Shanghai Institute of Optics and Mechanics successfully achieved the world's fir

Chen Weibiao, a researcher team of Shanghai Institute of Optics and Precision Machinery, Chinese Academy of Sciences, proposed a calibration device and method for atmospheric carbon dioxide concentration measurement based on the carbon dioxide absorption cell, which provides a new solution for the calibration of spaceborne carbon dioxide lidar concentration measurement accuracy laboratory.

The calibration device simulates the absorption process of the whole atmosphere to the spaceborne CO2 lidar by filling the sealed cavity with optical windows with CO2 at different pressures. This device has successfully calibrated the world's first CO2 detection lidar in the laboratory, which proves that the CO2 column concentration of the lidar system can achieve a high measurement accuracy of 1 ppm. Relevant research achievements are summarized in the form of "Calibration experiences based on CO2 absorption cell for 1.57 - μ M spaceborne IPDA LIDAR "was published in Optics Express.

For spaceborne carbon dioxide detection lidar, due to its large volume, heavy weight, complex system, especially high laser pulse energy, it will bring risks to spaceborne lidar when operating in outdoor environment, so it is difficult to verify the measurement accuracy of its carbon dioxide concentration through field testing.

This paper creatively uses the gas absorption cell to simulate the differential absorption of laser emission 1572 dual wavelength pulses under different atmospheric carbon dioxide concentrations by vacuuming and filling carbon dioxide at different pressures, and designs a calibration experiment for the carbon dioxide differential absorption lidar system. The calibration measurement results show that the absolute error and standard deviation of the CO2 column concentration measurement are less than 1 ppm, which verifies the high precision measurement capability of the spaceborne CO2 detection lidar.

This study verified the ability of using this type of calibration device to calibrate the measurement accuracy of carbon dioxide column concentration, and provided a feasible calibration scheme for the calibration of the lidar greenhouse gas remote sensing detection laboratory.

IPDA Lidar Calibration Test Principle Block Diagram

(LA: absorber, RM1-5: reflector, MM fiber: 1km multimode optical fiber, IS: integrating sphere)

a) Lidar CO2 concentration inversion results (148 pulse moving average) (b) Lidar CO2 concentration inversion results (296 pulse moving average)

Source: Shanghai Institute of Optics and Precision Machinery, Chinese Academy of Sciences