Development of Compact 1.6 μm DIAL System for Measurement of Lower-Atmospheric CO2 Concentration Distribution

Abstract:

For the detailed analysis of forest carbon dynamics and CO₂ fluxes of urban area, the CO₂ concentration measurement techniques with high spatial and temporal resolution are required in the lower atmosphere. We had developed the differential absorption lidar (DIAL) system to achieve high accurate measurements of vertical CO₂ profiles and the vertical distribution of CO₂ concentration from 2 km to 7 km altitude has been observed¹. In order to measure the CO₂ concentration distribution in the lower altitude, the dynamic range of the photon counter and the output power of transmitter of the CO₂ DIAL have improved. We develope the compact 1.6 μm CO₂ DIAL with the high-speed photon counter (10 GHz) and the small power transmitter to perform high-precision measurements of CO₂ concentration profiles in the lower atmosphere. This compact mobile DIAL system has a 2 mJ OPG transmitter and a 25 cm coaxial telescope for measurements of limitted range. As the transmitter beam of this DIAL system is able to scan from -4 degree to 52 degree with elevation angle, the vertical distribution of lower CO₂ concentration as well as the horizontal distribution from short range can be measured with high precision. The compact DIAL was conducted test observations and achieved successfully measurements of CO₂ concentration profiles for the range from 0.25 to 3 km with integration time of 30 minutes and range resolution of 300 m.

This work was financially supported by the System Development Program for Advanced Measurement and Analysis of the Japan Science and Technology Agency.

REFERENCES

1. Y. Shibata, C. Nagasawa, M. Abo, Proc. SPIE 8894, 889406 (2013); doi: 10.1117/12.2029359