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Proceedings Paper • Open Access

The challenges of measuring methane from space with a lidar
Author(s): H. Riris; K. Numata; S. Wu; M. Fahey; B. Gonzalez; X. Sun; J. Mao; M. Rodriguez

Paper Abstract

The global and regional quantification of methane fluxes and identification of its sources and sinks has been highlighted as one of the goals of the NASA 2017 Earth Science Decadal Survey. Detecting methane from space and airborne platforms with an active (laser) remote sensing instrument presents several unique technology and measurement challenges. The instrument must have a single frequency, narrow-linewidth light source, and photon-sensitive detector at the right spectral region to make continuous measurements from orbit, day and night, all seasons and at all latitudes. It must have a high signal to noise ratio and must be relatively immune to biases from aerosol/cloud scattering, spectroscopic and meteorological data uncertainties, and instrument systematic errors.
At Goddard Space Flight Center (GSFC), in collaboration with industry, we have developed an airborne instrument to measure methane. Our instrument is a nadir-viewing lidar that uses Integrated Path Differential Absorption (IPDA), to measure methane near 1.65 μm. We sample the absorption line using multiple wavelengths from a narrow linewidth laser source and a sensitive photodetector. This measurement approach provides maximum information content about the CH4 column, and minimizes biases in the XCH4 retrieval.
In this paper, we will review our progress to date and discuss the technology challenges, options and tradeoffs to measure methane from space and airborne platforms.

Paper Details

Date Published: 12 July 2019
PDF: 10 pages
Proc. SPIE 11180, International Conference on Space Optics — ICSO 2018, 1118027 (12 July 2019); doi: 10.1117/12.2535998
Show Author Affiliations
H. Riris, Goddard Space Flight Ctr. (United States)
K. Numata, Goddard Space Flight Ctr. (United States)
S. Wu, Goddard Space Flight Ctr. (United States)
M. Fahey, Goddard Space Flight Ctr. (United States)
B. Gonzalez, Goddard Space Flight Ctr. (United States)
X. Sun, Goddard Space Flight Ctr. (United States)
J. Mao, Univ. of Maryland (United States)
M. Rodriguez, Sigma Space (United States)

Published in SPIE Proceedings Vol. 11180:
International Conference on Space Optics — ICSO 2018
Zoran Sodnik; Nikos Karafolas; Bruno Cugny, Editor(s)

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