title: Demonstration of an ethane spectrometer for methane source identification.
abstract: Methane is an important greenhouse gas and tropospheric ozone precursor. Simultaneous observation of ethane with methane can help identify specific methane source types. Aerodyne Ethane-Mini spectrometers, employing recently available mid-infrared distributed feedback tunable diode lasers (DFB-TDL), provide 1 s ethane measurements with sub-ppb precision. In this work, an Ethane-Mini spectrometer has been integrated into two mobile sampling platforms, a ground vehicle and a small airplane, and used to measure ethane/methane enhancement ratios downwind of methane sources. Methane emissions with precisely known sources are shown to have ethane/methane enhancement ratios that differ greatly depending on the source type. Large differences between biogenic and thermogenic sources are observed. Variation within thermogenic sources are detected and tabulated. Methane emitters are classified by their expected ethane content. Categories include the following: biogenic (<0.2%), dry gas (1-6%), wet gas (>6%), pipeline grade natural gas (<15%), and processed natural gas liquids (>30%). Regional scale observations in the Dallas/Fort Worth area of Texas show two distinct ethane/methane enhancement ratios bridged by a transitional region. These results demonstrate the usefulness of continuous and fast ethane measurements in experimental studies of methane emissions, particularly in the oil and natural gas sector.
authors.affiliation: Aerodyne Research Inc., Billerica, Massachusetts 01821, United States.
authors.forename: Tara I
authors.initials: TI
authors.lastname: Yacovitch
authors.forename: Scott C
authors.initials: SC
authors.lastname: Herndon
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Roscioli
authors.forename: Cody
authors.initials: C
authors.lastname: Floerchinger
authors.forename: Ryan M
authors.initials: RM
authors.lastname: McGovern
authors.forename: Michael
authors.initials: M
authors.lastname: Agnese
authors.forename: Gabrielle
authors.initials: G
authors.lastname: Pétron
authors.forename: Jonathan
authors.initials: J
authors.lastname: Kofler
authors.forename: Colm
authors.initials: C
authors.lastname: Sweeney
authors.forename: Anna
authors.initials: A
authors.lastname: Karion
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Conley
authors.forename: Eric A
authors.initials: EA
authors.lastname: Kort
authors.forename: Lars
authors.initials: L
authors.lastname: Nähle
authors.forename: Marc
authors.initials: M
authors.lastname: Fischer
authors.forename: Lars
authors.initials: L
authors.lastname: Hildebrandt
authors.forename: Johannes
authors.initials: J
authors.lastname: Koeth
authors.forename: J Barry
authors.initials: JB
authors.lastname: McManus
authors.forename: David D
authors.initials: DD
authors.lastname: Nelson
authors.forename: Mark S
authors.initials: MS
authors.lastname: Zahniser
authors.forename: Charles E
authors.initials: CE
authors.lastname: Kolb
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000401:Aircraft; D003198:Computer Simulation; D004980:Ethane / Q000032:analysis*; D019015:Geologic Sediments / Q000737:chemistry; D008697:Methane / Q000032:analysis*; D013057:Spectrum Analysis / Q000295:instrumentation* / Q000379:methods*; D013781:Texas
chemical_list: D000393:Air Pollutants; D004980:Ethane; D008697:Methane