Airborne measurements of CO₂ column absorption and range using a pulsed direct-detection integrated path differential absorption lidar

Abstract

We report on airborne CO 2 column absorption measurements made in 2009 with a pulsed directdetection lidar operating at 1572.33 nm and utilizing the integrated path differential absorption technique. We demonstrated these at different altitudes from an aircraft in July and August in flights over four locations in the central and eastern United States. The results show clear CO 2 line shape and absorption signals, which follow the expected changes with aircraft altitude from 3 to 13 km. The lidar measurement statistics were also calculated for each flight as a function of altitude. The optical depth varied nearly linearly with altitude, consistent with calculations based on atmospheric models. The scatter in the optical depth measurements varied with aircraft altitude as expected, and the median measurement precisions for the column varied from 0.9 to 1.2 ppm. The altitude range with the lowest scatter was 8-10 km, and the majority of measurements for the column within it had precisions between 0.2 and 0.9 ppm.

Airborne Measurements of CO2 Column Concentration and Range Using a Pulsed Direct-Detection IPDA Lidar

“…Our airborne lidar [21][22][23][24] was developed to demonstrate a dual-channel pulsed IPDA approach as a candidate for the ASCENDS mission, and a description of its configuration and its performance during flights in 2009 has been recently summarized [25]. The approach uses two tunable pulsed laser transmitters allowing simultaneous measurement of the absorption from a CO 2 absorption line in the 1,570 nm band, O 2 extinction in the oxygen A-band, and surface height and atmospheric backscatter in the same path.…”

“…For these flights on the NASA DC-8 aircraft [32] we adapted the previous version of the airborne lidar [25] flown on the NASA Glenn Lear-25 aircraft in 2009. A photograph of the flight configuration is shown in Figure 1.…”

Methane optical density measurements with an integrated path differential absorption lidar from an airborne platform

“…[21][22][23][24][25][26][27][28][29][30][31] Using the instrument in a sounding (surface reflection) mode enables integrated column trace gas measurements from orbit with relatively modest laser power.…”

Retrieval of methane source strengths in Europe using a simple modeling approach to assess the potential of spaceborne lidar observations

“…There are several planned space-and aircraft-based instruments that will use laser technology to measure the total CH 4 column (Riris et al, 2013;Ehret et al, 2008) and total CO 2 column (Abshire et al, 2010). This approach should remedy some of the current issues concerning highlatitude coverage and scattering from clouds and aerosols.…”

“…This approach should remedy some of the current issues concerning highlatitude coverage and scattering from clouds and aerosols. Indeed, a recent aircraft demonstration campaign to test the feasibility of lasers to measure CO 2 has successfully retrieved CO 2 concentrations in thin cloud conditions (A. Ramanathan, personal communication, 2013;Abshire et al, 2013). In the frame of a German-French climate monitoring initiative, DLR (Deutsches Zentrum für Luft-und Raumfahrt) and CNES (Centre National d'Etudes Spatiales) proposed a MEthane Remote LIdar MissioN (MERLIN) on a small polar orbiting satellite.…”