Work Description

For questions or information, contact the PI Dr. E. A. Kort at eakort@umich.edu

Flare intercept locations in the Flaring & Fossil Fuels: Uncovering
Emissions & Losses (F3UEL) airborne dataset.

Methodology:

Data was collected by a Mooney aircraft platform (Scientific Aviation), sampling natural gas flaring infrastructure in the Permian, Eagle Ford, and Bakken regions of the United States. Measurements of methane (CH4), carbon dioxide (CO2), and water vapor (H2O), are collected with the Picarro model 2301-f instrument (wavelength-scanned cavity ringdown spectrometer). Measurements were made at a frequency of 0.33 to 0.5 Hz with an uncertainty of 1.4 ppb CH4. GPS antennae, mounted on the Mooney aircraft, recorded latitude, longitude, altitude, aircraft heading, zonal speed, and meridional speed. Horizontal winds are calculated following Conley et al (2014) . Temperature (C) and humidity (%) were collected with the Vaisala HMP60 probe.

Flare methane destruction removal efficiencies (DRE) are estimated using the in-situ sampling of CO2 and CH4 in flare combustion plumes as described in Plant et. al (2022).

This method design captures the population level statistics of DRE across a basin. This dataset is not designed for attribution of specific DRE values to specific facilities. Plumes from flares often exhibit complex behavior that means average wind vectors at the point of measurement do not simply trace back to the origin of the plume.

References:

Conley, S. A., Faloona, I. C., Lenschow, D. H., Karion, A., & Sweeney, C. (2014). A low-cost system for measuring horizontal winds from single-engine aircraft. Journal of Atmospheric and Oceanic Technology, 31(6), 1312-1320.

Plant, G., Kort, E. A., Brandt, A. R., Chen, Y., Fordice, G., Gorchov Negron, A. M., ... & Zavala-Araiza, D. (2022). Inefficient and unlit natural gas flares both emit large quantities of methane. Science, 377(6614), 1566-1571.

Description:

As part of the Flaring & Fossil Fuels: Uncovering Emissions & Losses (F3UEL) project, the aircraft measurement platform sampled downwind of flares in the Permian and Eagle Ford regions of Texas (2020) and the Bakken in North Dakota (2021). Estimates of methane destruction removal efficiency are calculated for each airborne intercept of a flare combustion plume based on the observed enhancements of carbon dioxide and methane, along with assumptions about the flare gas composition. Locations provided are the GPS coordinates for the aircraft sampling, not of the upwind flare infrastructure on the ground. Attempts to link the airborne sampling locations to ground infrastructure using the provided wind information (measured at the aircraft), should take care to account for complexities of transport in the atmosphere.

Column names:

datetime
basin
flareUniqueID
interceptLon_deg
interceptLat_deg
avgWind_m_s
wd_rad
ch4DRE_per

Column descriptions:

datetime: date and time of airborne sampling (EDT)
basin: sampled oil & gas basin/region
flareUniqueID: Unique id for individual flares based on *approximate* intercept grouping based on sampling location and wind direction (format: d=date, s=sampling region#, f=flare#)
interceptLon_deg: Longitude of flare plume intercept in flight track
interceptLat_deg: Latitude of flare plume intercept in flight track
avgWind_m_s: Average wind speed measured at the aircraft over each flare sampling region, m/s
wd_rad: Wind vector (or arrow) direction, based on winds measured at the aircraft, radians **Further information below.
ch4DRE_per: Estimated methane destruction removal efficiency (DRE) calculated for each intercept.

**The wind vector angle (wd_rad, units=radians) follows the unit circle where 0=East, postive numbers=counter clockwise, range=-pi:pi, consistent with most programming languages. This value is calculated as atan2(V,U) where U,V are the horizontal components of the wind speed. U (parallel to the x-axis, i.e. longitude) is positive when wind is coming from the West, and V (parallel to y-axis, i.e. latitude) is positive when wind is coming from the South. The meteorological wind direction (the direction from where the wind originates, 0 deg = North, clockwise) in degrees is (270-atan2(V,U)*180/pi)%%360, where atan2(V,U) is the provided 'wd_rad' variable and '%%' is the modulus operator to ensure that the output is between 0 and 360 degrees. 'atan2' is the arc tangent function that handles the possibility that U can be zero.

More information about the airborne sampling, flare identification, and DRE calculation available in:
Plant G, Kort EA, Brandt A, Chen Y, Fordice G, Gorchov Negron AM, Schwietzke S, Smith M, Zavala-Araiza D, Inefficient and
unlit natural gas flares both emit large quantities of methane, Science, https://doi.org/10.1126/science.abq0385, 2022.

The full F3UEL airborne data is available at:
Kort, E. A., Plant, G., Brandt, A. R., Chen, Y., Gorchov Negron, A. M., Schwietzke, S.,
Smith, M. L., Zavala-Araiza, D. (2022). Aircraft Data (2021) for Flaring & Fossil Fuels: Uncovering
Emissions & Losses (F3UEL) [Data set], University of Michigan - Deep Blue Data. https://doi.org/10.7302/6tgq-e116

Kort, E. A., Plant, G., Smith, M. L., Brandt, A. R., Chen, Y., Gorchov Negron, A. M., Schwietzke, S.,
Zavala-Araiza, D. (2022). Aircraft Data (2020) for Flaring & Fossil Fuels: Uncovering Emissions &
Losses (F3UEL) [Data set], University of Michigan - Deep Blue Data. https://doi.org/10.7302/1xjm-3v49