Atmospheric remote sensing constraints on direct sea-air methane flux from the 22/4b North Sea massive blowout bubble plume. (December 2015)

• Record Type: Journal Article
• Authors: Gerilowski, Konstantin; Krings, Thomas; Hartmann, Jörg; Buchwitz, Michael; Sachs, Torsten; Erzinger, Jörg; Burrows, John P.; Bovensmann, Heinrich
• Is Part Of: Marine and petroleum geology. Volume 68:Part B(2015:Dec.)
• Page Start: 824
• Page End: 835
• Publication Date: 2015-12
• Subjects: Remote sensing -- Glint -- Aircraft -- Methane -- Blowout -- Emission estimate; Submarine geology -- Periodicals; Petroleum -- Geology -- Periodicals; Géologie sous-marine -- Périodiques; Pétrole -- Géologie -- Périodiques; Petroleum -- Geology; Submarine geology; Periodicals; Electronic journals; 551.468
• DOI: 10.1016/j.marpetgeo.2015.07.011
• Languages: English
• ISSNs: 0264-8172

Abstract

Abstract: A new airborne remote sensing approach to estimate an upper limit of the direct sea-air methane emission flux was applied over the 22/4b blowout site located at N57.92°, E1.63° in the North Sea. Passive remote sensing data using sunglint/sunglitter geometry were collected during instrumental tests with the Methane Airborne MAPper – MAMAP – instrument installed aboard the Alfred Wegener Institute (AWI) Polar-5 aircraft on 3. June 2011. MAMAP is a passive short wave infrared (SWIR) remote sensing spectrometer for airborne measurements and retrieval of the atmospheric column-averaged dry air mole fractions of methane (XCH4 ) and carbon dioxide (XCO2 ). In addition to MAMAP a fast CH4 in-situ analyzer (Los-Gatos Research Inc. RMT-200), two 5-hole turbulence probes and the Polar-5 basic sensor suite comprising different temperature, pressure, humidity and camera sensors were installed aboard the aircraft. The collected MAMAP remote sensing data acquired in the vicinity of the 22/4b blowout site showed no detectable increase in the derived XCH4 (with respect to the atmospheric background). Based on the absence of a detectable XCH4 column increase, an approximate top-down upper-limit for the direct atmospheric 22/4b blowout CH4 emissions from the main bubble plume of less than 10 ktCH4 /yr has been derived. The constraint has been determined by comparing XCH4 information derived by the remote sensing measurements with results obtained from a Gaussian plume forward model simulation taking into account the actual flight track, the instrument sensitivity and measurement geometry, as well as the prevailing atmospheric conditions. Highlights: A new remote sensing approach for estimating direct atmospheric CH4 emissions from offshore blowout accidents. A new upper limit estimate of the direct atmospheric CH4 emissions from the 22/4b blowout site to below 10 ktCH4 /y. Airborne short wave infrared (SWIR) atmospheric CH4 remote sensing in solar glint direction over the ocean.