Backscatter 2-$\mu\hbox{m}$ Lidar Validation for Atmospheric $\hbox{CO}_{2}$ Differential Absorption Lidar Applications

Abstract

A 2-µm backscatter lidar system has been developed by utilizing tunable pulsed laser and infrared phototransistor for the transmitter and the receiver, respectively. To validate the system, the 2-µm atmospheric backscatter profiles were compared to profiles obtained at 1 and 0.5 µm using avalanche photodiode and photomultiplier tube, respectively. Consequently, a methodology is proposed to compare the performance of different lidar systems operating at different wavelengths through various detection technologies. The methodology is based on extracting the system equivalent detectivity and comparing it to that of the detectors, as well as the ideal background detectivity. Besides, the 2-µm system capability for atmospheric CO 2 temporal profiling using the differential absorption lidar (DIAL) technique was demonstrated. This was achieved by tuning the laser at slightly different wavelengths around the CO 2 R22 absorption line in the 2.05-µm band. CO 2 temporal profiles were also compared to in situ measurements. Preliminary results indicated average mixing ratios close to 390 ppm in the atmospheric boundary layer with 3.0% precision. The development of this system is an initial step for developing a high-resolution, high-precision direct-detection atmospheric CO 2 DIAL system. A successful development of this system would be a valuable tool in obtaining and validating global atmospheric CO 2 measurements.

InP-Based Active and Passive Components for Communication Systems at 2 μm

“…The earth's atmosphere has excellent transmission at 2 μm with the result that the 3-D distribution of CO 2 can be accurately mapped remotely using differential absorption LIDAR systems [2], [3]. Enhanced sensitivity can be achieved by the use of coherent detection [4].…”

Column Co2 measurement from an airborne solid state double-pulsed 2-micron integrated path differential absorption lidar

“…Active remote sensing of CO 2 is an alternative technique that has the potential to overcome the limitation of the passive sensors. CO 2 active remote sensing has been demonstrated using the differential absorption lidar (DIAL) technique [13][14][15][16][17][18][19][20][21]. Both 1.6 and 2.0 µm are suitable for atmospheric CO 2 measurements due to the existence of distinct absorption feathers for the gas at these particular wavelengths.…”

A robust optical parametric oscillator and receiver telescope for differential absorption lidar of greenhouse gases

“…There are a number of choices of wavelength region for DIAL systems, including CO 2 systems at 1.6 µm [3,6] and 2 µm [7]. We choose the 1.6 µm region because a profusion of telecommunications devices, particularly high-sensitivity detectors [8], operate in this wavelength region. It also provides access to CH 4 absorption lines [9].…”