Atmospheric characterization through fused mobile airborne and surface in situ surveys: methane emissions quantification from a producing oil field
Methane (CH<sub>4</sub>) inventory uncertainties are large, requiring robust emission derivation approaches. We report on a fused airborne–surface data collection approach to derive emissions from an active oil field near Bakersfield, central California. The approach characterizes the...
| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-03-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://www.atmos-meas-tech.net/11/1689/2018/amt-11-1689-2018.pdf |
| Summary: | Methane (CH<sub>4</sub>) inventory uncertainties are large, requiring
robust emission derivation approaches. We report on a fused airborne–surface
data collection approach to derive emissions from an active oil field near
Bakersfield, central California. The approach characterizes the atmosphere
from the surface to above the planetary boundary layer (PBL) and combines
downwind trace gas concentration anomaly (plume) above background with normal
winds to derive flux. This approach does not require a well-mixed PBL; allows
explicit, data-based, uncertainty evaluation; and was applied to complex
topography and wind flows.
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In situ airborne (collected by AJAX – the Alpha Jet Atmospheric
eXperiment) and mobile surface (collected by AMOG – the AutoMObile trace Gas
– Surveyor) data were collected on 19 August 2015 to assess source strength.
Data included an AMOG and AJAX intercomparison transect profiling from the
San Joaquin Valley (SJV) floor into the Sierra Nevada (0.1–2.2 km
altitude), validating a novel surface approach for atmospheric profiling by
leveraging topography. The profile intercomparison found good agreement in
multiple parameters for the overlapping altitude range from 500 to 1500 m
for the upper 5 % of surface winds, which accounts for wind-impeding
structures, i.e., terrain, trees, buildings, etc. Annualized emissions from
the active oil fields were 31.3 ± 16 Gg methane and
2.4 ± 1.2 Tg carbon dioxide. Data showed the PBL was not well mixed at
distances of 10–20 km downwind, highlighting the importance of the
experimental design. |
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| ISSN: | 1867-1381 1867-8548 |