A23B-0288
Technology Advancements for Active Remote Sensing of Carbon Dioxide from Space using the ASCENDS CarbonHawk Experiment Simulator
Tuesday, 15 December 2015
Poster Hall (Moscone South)
Michael D Obland1, Amin R Nehrir1, Zhaoyan Liu1, Songsheng Chen1, Joel F Campbell1, Bing Lin1, Susan A Kooi2, Tai-Fang Fan3, Yonghoon Choi2, James Plant1, Melissa M Yang1, Edward V Browell4, Fenton W Harrison1, Byron Meadows1, Jeremy T Dobler5 and T Scott Zaccheo6, (1)NASA Langley Research Center, Hampton, VA, United States, (2)Science Systems and Applications, Inc. Hampton, Hampton, VA, United States, (3)SSAI, Hampton, VA, United States, (4)STARSS II Affiliate, Hampton, VA, United States, (5)ITT Space Systems, LLC, Fort Wayne, IN, United States, (6)Atmospheric and Environmental Research Lexington, Lexington, MA, United States
Abstract:
This work describes advances in critical lidar technologies and techniques developed as part of the ASCENDS CarbonHawk Experiment Simulator (ACES) system for measuring atmospheric column carbon dioxide (CO2) mixing ratios in support of the NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission. The ACES design demonstrates advancements in: (1) enhanced power-aperture product through the use and operation of multiple co-aligned laser transmitters and a multi-aperture telescope design; (2) high-efficiency, high-power Erbium-Doped Fiber Amplifiers (EDFAs); (3) high-bandwidth, low-noise HgCdTe detector and transimpedence amplifier (TIA) subsystem capable of long-duration operation; and (4) advanced algorithms for cloud and aerosol discrimination. The ACES instrument, an Intensity-Modulated Continuous-Wave (IM-CW) lidar, was designed for high-altitude aircraft operations and can be directly applied to space instrumentation to meet the ASCENDS mission requirements. Specifically, the lidar simultaneously transmits three IM-CW laser beams from the high power EDFAs operating near 1571 nm. The outgoing laser beams are aligned to the field of view of three fiber-coupled 17.8-cm diameter telescopes, and the backscattered light collected by the same three telescopes is sent to the detector/TIA subsystem, which has a bandwidth of 4.9 MHz and operates service-free with a tactical Dewar and cryocooler. The electronic bandwidth is only slightly higher than 1 MHz, effectively limiting the noise level. Two key laser modulation approaches are being tested to significantly mitigate the effects of thin clouds on the retrieved CO2 column amounts. This work provides an over view of these technologies, the modulation approaches, and results from recent test flights.
