A128-07
Measuring Atmospheric CO2 Enhancements from Wildfires with a Pulsed IPDA Lidar

Friday, 11 December 2020: 10:48
Virtual
Jianping Mao, University of Maryland College Park, College Park, MD, United States, James B. Abshire, NASA Goddard Space Flight Ctr, Greenbelt, MD, United States, Stephan R Kawa, NASA Goddard SFC, Greenbelt, MD, United States, Haris Riris, NASA GSFC, Greenbelt, MD, United States, Xiaoli Sun, NASA Goddard Space Flight Center, Greenbelt, MD, United States and Niels Andela, Cardiff University, School of Earth and Ocean Sciences, Cardiff, United Kingdom
Abstract:
Wildfires are a major source of greenhouse gases. Fires were responsible for up to a fifth as much as carbon released in 2019 from burning fossil fuels. The estimates of CO2 emissions from fires from fire emission models or databases have large discrepancies and uncertainties. Ground-based and airborne measurements of fire emissions are few and difficult to obtain, and atmospheric column-averaged CO2 (XCO2) retrievals from satellite measurements are significantly degraded by the scattering of smoke in the scene.

NASA Goddard Space Flight Center has developed an integrated-path, differential absorption (IPDA) lidar approach to measure global XCO2 from space as a candidate for NASA’s Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission (Kawa et al., 2018). Measurements of time-resolved laser backscatter profiles from the atmosphere allow this technique to estimate XCO2 and range to any significant reflective surfaces with precise knowledge of the photon path-length even in the presence of atmospheric scattering (Abshire et al., AMT, 2018).

We demonstrate this measurement capability using airborne lidar measurements from summer 2017 ASCENDS/ABoVE airborne science campaign. During the August 8 return flight from Alaska to California over Vancouver Island, there were dense smoke plumes from fires in the Canadian Rockies. Over this region, the retrievals from our lidar measurements showed ~5 ppm enhancements in XCO2. For validation, a spiral-down comparison to in situ CO2 measurements was performed at Moses Lake airport in the central Washington just after the region of XCO2 enhancement. We have also compared this enhancement with that from the Goddard Parameterized Chemistry Transport Model (PCTM) using the Global Fire Emission Database (GFED) and found the CO2 emissions from the record-breaking wildfires in British Columbia in 2017 were underestimated in GFED4 by about a factor of 2.

The results show that a future spaceborne XCO2 lidar mission with these capabilities will improve fire emission modeling and carbon flux estimation. More details will be shown in the presentation.

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