The CU Airborne Solar Occultation Flux Instrument: Performance Evaluation during BB-FLUX

Kille, Natalie; Zarzana, Kyle J.; Alvarez, Johana Romero; Lee, Christopher F.; Rowe, Jake P.; Howard, Benjamin; Campos, T.; Hills, A. J.; Hornbrook, R. S.; Ortega, Ivan; Permar, Wade; Ku, I-Ting; Lindaas, Jakob; Pollack, I. B.; Sullivan, A. P.; Zhou, Yong; Fredrickson, Carley D.; Palm, Brett B.; Peng, Qiaoyun; Apel, E. C.; Hu, Lu; Collett, Jeffrey L.; Fischer, Emily V.; Flocke, Frank; Hannigan, J. W.; Volkamer, Rainer

doi:10.1021/acsearthspacechem.1c00281

Cited by 10 publications

(20 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Several aircraft campaigns examining wildfires were conducted in the northwestern United States during the summer of 2018, including the Western Wildfire Experiment for Cloud Chemistry, Aerosol Absorption, and Nitrogen (WE-CAN; e.g., Permar et al; Juncosa Calahorrano et al; Lindaas et al) and the Biomass Burning Fluxes of Trace Gases and Aerosols field campaign (BB-FLUX; Volkamer et al , ). The BB-FLUX campaign incorporated the use of innovative remote sensing instruments developed to better quantify emission fluxes of trace gases from wildfires. ,− From the foundation provided in Kille et al, airborne CO column measurements can be compared with those measured by satellites. This study focuses on TROPOMI onboard the Sentinel-5 Precursor (S-5P) satellite, which provides total vertical column measurements of CO and methane (CH 4 − ) with daily global coverage at high spatial resolution retrieved from the shortwave-infrared (SWIR) measurements.…”

Section: Introductionmentioning

confidence: 99%

Carbon Monoxide in Optically Thick Wildfire Smoke: Evaluating TROPOMI Using CU Airborne SOF Column Observations

Rowe

Zarzana

Kille

et al. 2022

ACS Earth Space Chem.

Self Cite

View full text Add to dashboard Cite

TROPOspheric Monitoring Instrument (TROPOMI) measurements of carbon monoxide (CO) vertical column enhancements in optically thick biomass burning plumes were evaluated using measurements from the University of Colorado Airborne Solar Occultation Flux (CU AirSOF) instrument during the 2018 Biomass Burning Fluxes of Trace Gases and Aerosols (BB-FLUX) field campaign in the northwestern United States. The different temporal and spatial scales and measurement geometries sampled from the aircraft and satellite are actively accounted for by (1) focusing on coincident measurements, (2) comparing spatial integrals of CO enhancements across plume transects, (3) using the FLEXible PARTicle (FLEXPART) dispersion model to correct for atmospheric transport, and (4) accounting for Averaging Kernels (AVK). TROPOMI is found to be systematically higher relative to the aircraft by +36% for the operational product (+27% preoperational product) without geospatial and temporal corrections. Consecutive transects by CU AirSOF revealed significant variations between integrated CO enhancements (on average 28% over 30 min) on the satellite sub-pixel scale. When the additional corrections are applied (FLEXPART, and to a lesser degree also AVK), the average bias is reduced to +10% for the operational product (+7.2% preoperational), which is insignificant within 15% uncertainty (variability among case studies, 95% confidence level). Radiative transfer simulations in synthetic plumes indicate that multiple scattering can enhance satellite CO signals by 5−10% at high aerosol loads, which warrants further attention. Smoke strongly reduces trace gas measurements at ultraviolet and visible wavelengths (by up to a factor of 6), highlighting the importance of multispectral aerosol properties in thick smoke.

show abstract

Section: Introductionmentioning

confidence: 99%

Carbon Monoxide in Optically Thick Wildfire Smoke: Evaluating TROPOMI Using CU Airborne SOF Column Observations

Rowe

Zarzana

Kille

et al. 2022

ACS Earth Space Chem.

Self Cite

View full text Add to dashboard Cite

show abstract

“…CU AirSOF provides a promising new tool that has begun to be utilized to investigate ecosystem‐atmosphere linkages (BB‐FLUX campaign; Volkamer et al., 2020). Quantifying emission mass fluxes by CU AirSOF is not limited to CO, but has been extended to measurements of other trace gases that absorb light at mid‐infrared wavelengths (Kille et al., 2022). The CU AirSOF measurements enable the calculation of the emission coefficient C e from satellite FRP, now provided at high frequency by geostationary measurements.…”

Section: Discussionmentioning

confidence: 99%

“…The CU AirSOF instrument is a unique prototype (Kille et al., 2022) and is optimized to quantify wildfire emissions due to its ability to capture VCDs of trace gases above the aircraft through thick smoke plumes. CU AirSOF is conceptually similar to ground‐based solar Fourier‐transform infrared spectroscopy (FTIR) instruments, which provide long‐term stationary column measurements at much higher spectral resolution relying on plume portions to pass over the instrument location (Lutsch et al., 2020; Paton‐Walsh et al., 2004), but is optimized for mobile aircraft deployment downwind of fires.…”

Section: Methodsmentioning

confidence: 99%

“…The CU AirSOF instrument (Kille et al., 2022) consists of a Fourier Transform Spectrometer installed on a research aircraft, and uses a custom‐built digital fast solar tracker (Baidar et al., 2016) to point directly at the sun to measure trace gas vertical column densities (VCDs) above the aircraft at mid‐infrared wavelengths. CU AirSOF is a further development of the ground‐based CU mobile SOF instrument, which has been used to quantify emissions from area sources (Ibrahim et al., 2010; Kille et al., 2017, 2019; Mellqvist et al., 2010).…”

Section: Methodsmentioning

confidence: 99%

“…The first deployment of the CU AirSOF instrument (Kille et al., 2022) quantified the emission fluxes of the N. CA wildfires on 10 October 2017. These are the first CO emission flux quantifications using airborne CO column measurements on the scale of actual wildfires.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Quantifying Carbon Monoxide Emissions on the Scale of Large Wildfires

Béla

Kille

McKeen

et al. 2022

Geophysical Research Letters

Self Cite

View full text Add to dashboard Cite

The October 2017 fires near Santa Rosa in northern California (N. CA) were the second most destructive fires to date in California 12 , killing 44 people 13 , destroying nearly 9,000 structures 13,14 , with reported losses of over $10 billion 14 , and resulting in the highest particulate matter (PM2.5) levels recorded in the Bay Area since 1999 15 . The Tubbs fire, the largest of the Oct. 2017 N. CA fires, which devastated the city of Santa Rosa, was started by a private electrical system 16 , and was associated with an intense terrain-induced downslope windstorm 17 . Such windstorms, commonly known as "Santa Ana" or "Diablo" winds, can be very destructive when driving fires and are projected with climate change to extend the fire season later into the fall and winter 17 .The Oct. 2017 N. CA fires are an example of fires with anthropogenic ignition sources and their subsequent air quality impacts that are likely to increase due to a warmer and drier climate in the Western U.S. during the 21 st century 18,19,20,21 . These trends combined with rising numbers of humans living in the urban-wildland interface are likely to result in increases in population exposure to fire activity 22 and poor air quality episodes 23 . Long-term exposure to elevated PM2.5 may increase human susceptibility to respiratory diseases such as coronavirus (COVID-19) 24,25 .The University of Colorado Airborne Solar Occultation Flux (CU AirSOF) instrument was deployed to quantify the emission fluxes of the N. CA wildfires on Oct. 10, 2017. CU AirSOF consists of a Fourier Transform Spectrometer installed on a research aircraft, and uses a digital fast solar tracker to point directly at the sun to measure the total CO column above the aircraft at mid-infrared wavelengths 26,27 . The SOF method has been used to quantify emissions from area sources by mass balance 28,29,30 , but its potential to study wildfires remains largely unexplored. The CU AirSOF instrument is a unique prototype, and optimized to quantify wildfire emissions due to

show abstract

Airborne Emission Rate Measurements Validate Remote Sensing Observations and Emission Inventories of Western U.S. Wildfires

Stockwell

Béla

Coggon

et al. 2022

Environ. Sci. Technol.

View full text Add to dashboard Cite

Carbonaceous emissions from wildfires are a dynamic mixture of gases and particles that have important impacts on air quality and climate. Emissions that feed atmospheric models are estimated using burned area and fire radiative power (FRP) methods that rely on satellite products. These approaches show wide variability and have large uncertainties, and their accuracy is challenging to evaluate due to limited aircraft and ground measurements. Here, we present a novel method to estimate fire plume-integrated total carbon and speciated emission rates using a unique combination of lidar remote sensing aerosol extinction profiles and in situ measured carbon constituents. We show strong agreement between these aircraft-derived emission rates of total carbon and a detailed burned area-based inventory that distributes carbon emissions in time using Geostationary Operational Environmental Satellite FRP observations (Fuel2Fire inventory, slope = 1.33 ± 0.04, r 2 = 0.93, and RMSE = 0.27). Other more commonly used inventories strongly correlate with aircraftderived emissions but have wide-ranging over-and under-predictions. A strong correlation is found between carbon monoxide emissions estimated in situ with those derived from the TROPOspheric Monitoring Instrument (TROPOMI) for five wildfires with coincident sampling windows (slope = 0.99 ± 0.18; bias = 28.5%). Smoke emission coefficients (g MJ −1 ) enable direct estimations of primary gas and aerosol emissions from satellite FRP observations, and we derive these values for many compounds emitted by temperate forest fuels, including several previously unreported species.

show abstract

The CU Airborne Solar Occultation Flux Instrument: Performance Evaluation during BB-FLUX

Cited by 10 publications

References 64 publications

Carbon Monoxide in Optically Thick Wildfire Smoke: Evaluating TROPOMI Using CU Airborne SOF Column Observations

Carbon Monoxide in Optically Thick Wildfire Smoke: Evaluating TROPOMI Using CU Airborne SOF Column Observations

Quantifying Carbon Monoxide Emissions on the Scale of Large Wildfires

Airborne Emission Rate Measurements Validate Remote Sensing Observations and Emission Inventories of Western U.S. Wildfires

Contact Info

Product

Resources

About