Carbon Dioxide Active Remote Sensing Using Pulsed 2-µm Lidar

A pulsed 2-mm Integrated Path Differential Absorption (IPDA) lidar was developed at NASA Langley Research Center for high-accuracy and high-precision measurements of atmospheric carbon dioxide (CO2). The instrument targets the R30 CO2 absorption line and implements high-energy tunable on-line transmitter and advanced HgCdTe avalanche photodiode receiver. During 2019 airborne validation campaign, the IPDA was tested over the ocean for retrieving the weighted-average column dry-air volume mixing ratio of CO2 (XCO2) from 4.5 km altitude. XCO2 measurement resulted in 404.43 ± 1.23 ppm using 10 s average, as compared to 405.49 ppm from prediction models. This translates to 0.26% and 0.30% relative accuracy and precision, respectively. Performance models were updated to scale the IPDA technology assuming operation from a space platform. Results present XCO2 measurements using the instrument capabilities considering different target scenarios for Earth’s surface. This demonstrates the potential for the IPDA technique and technology to achieve sustained global CO2 measurement.