A miniaturized laser heterodyne radiometer for global ground-based observations of column CO2 and CH4
Abstract
For the last ten years, our team at NASA Goddard Space Flight Center has been developing a low-cost (~$10K/ per instrument), portable, miniaturized laser heterodyne radiometer (mini-LHR) instrument that passively measures atmospheric column averaged carbon dioxide (XCO2) and methane (XCH4) with precisions of 1 ppm XCO2 and 10 ppb XCH4 for hourly data products. The mini-LHR is designed to operate in tandem with the sun photometers used by the Aerosol RObotic NETwork (AERONET). This partnership allows us to leverage the existing framework of AERONET's global ground network of more than 500 sites as well as providing simultaneous measurements of aerosols that are known to be a major source of error in retrievals of XCO2from passive nadir-viewing satellite observations. The mini-LHR weighs ~10 lbs, fits into a backpack, and is powered by two folding solar panels and a 12 V battery pack. Portability, quick set-up (under an hour), and the integrated solar panel power system mean that the mini-LHR can add ground validation data points where there is no electricity and where a permanent station such as TCCON does not exist. Potential deployment locations include wetlands, thawing permafrost, the tropics, the Amazon, sub-Saharan Africa, as well as locations without a power grid or with geopolitical conflict. Portability also means that mini-LHRs can be easily moved for side-by-side comparisons with other mini-LHRs and with TCCON which simplifies assessing instrument bias as well as accuracy. Like TCCON, the mini-LHR points directly at the sun with a narrow field-of-view and is insensitivity to cloud and aerosol scattering that is common to nadir-pointing passive satellite approaches. In our recent publication, (Palmer, et al., AMT, 12, 2579-2594, 2019 https://doi.org/10.5194/amt-12-2579-2019), we evaluated the impact of a proposed network of mini-LHRs through Observing System Simulation Experiments (OSSEs) and found that for a network with 50 strategically placed mini-LHRs, the potential improvement (which varies seasonally) ranged from 58 %-81% over southern lands, 47 %-76% over tropical lands, 71 %-92% over northern lands, and 64 %-91% globally. In June 2019, the patent for the mini-LHR was licensed to MACH 33 Engineering, LLC and plans are underway to manufacture this instrument and make it commercially available.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.A43P2932B
- Keywords:
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- 0305 Aerosols and particles;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0345 Pollution: urban and regional;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0394 Instruments and techniques;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 3394 Instruments and techniques;
- ATMOSPHERIC PROCESSES