The Airborne Methane Plume Spectrometer (AMPS): Quantitative imaging of methane plumes in real time (2016)

The Airborne Methane Plume Spectrometer (AMPS) is a mature instrument concept that is ready for development at the Jet Propulsion Laboratory (JPL). At its core is a novel high-resolution imaging spectrometer that records solar reflected light between 1.99 and 2.42 pm at 1 nm resolution, including strong methane (CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> ) bands in the short-wave infrared. The push-broom spectrometer will leverage recent advancements in grating design and large-format 2D focal plane arrays to enable - for the first time - the high spectral resolution necessary for trace gas retrievals combined with high-performance imaging capabilities developed for surface remote sensing. AMPS features a 36° field of view with 600 resolved spatial elements across track (1 mRad) and 431 pixels in the spectral dimension. All other aspects of the instrument, such as the telescope, cryo-cooler, image stabilizer, GPS, are identical to available airborne JPL spectrometers in operation. The AMPS design is based on the next generation Airborne Visible Infrared Imaging Spectrometer (AVIRIS-NG), which has been used for high resolution mapping of CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> concentrations from a controlled release experiment [1] and over existing natural gas fields [2]. A real time CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> plume detection capability originally developed for AVIRIS-NG and successfully demonstrated over oil fields [3] will also be implemented with AMPS. This will facilitate surveys over existing oil and gas fields to identify and attribute CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> emissions to individual point source locations, permit adaptive surveys with repeat imaging of suspected sources, and allow real time communication to site operators or ground crews equipped with additional instruments to verify observed plumes. AMPS will enable quantitative imaging of CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> plumes at unprecedented spatial resolution and precision. Using a slow moving platform such as a helicopter at 100 m flight altitude (60 m image swath) will permit imaging CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> enhancements at 10 cm spatial resolution and an unprecedented accuracy of 0.05 g CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> /m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . This will allow robust detection of CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> emissions as low as 0.17 m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> /h (6 standard cubic feet per hour), an order of magnitude smaller than what current airborne systems can detect. Using fixed-wing aircraft, AMPS can also be flown faster and higher (1 to 8 km flight altitude), thereby providing larger image swaths (0.6 to 4.8 km swaths respectively) and effective large scale surveys. Mapping CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> emissions to individual point source locations could allow site operators to identify and mitigate these emissions, which reflect both a potential safety hazard and lost revenue. For the regulatory and scientific communities, understanding the distribution (spatial, temporal) and size of these emissions is of interest given the large uncertainties associated with anthropogenic emissions, including industrial point source emissions and fugitive CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> from oil and gas infrastructure.