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Webinar: Growing Emission of Methane from the Warming Arctic Ocean? Year-round Satellite Data

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Thursday, 08 September 2016, 12:00

Thursday, September 8, 2016. 12:00 PM. Webinar: Growing Emission of Methane from the Warming Arctic Ocean? Year-round Satellite Data. Leonid Yurganov, University of Maryland, Baltimore County, Joint Center for Earth Systems Technology. Sponsored by NOAA Center for Satellite Applications and Research. More information here.

 

Warming of the Arctic stimulated speculations about dissociation of methane hydrates in the Arctic seabed and a new climatic positive feedback that could induce a run-away global warming. Measurements of methane concentrations over the Arctic seas are rare and non-systematic. Here, for the first time, methane low tropospheric satellite data, provided by the NOAA retrieving code NUCAPS over the Arctic from AIRS/Aqua, IASI/MetOp-A, and IASI/MetOp-B were validated and analyzed. Methane retrievals over open water with a high vertical thermal contrast in the troposphere were found to be reliable. The methane seasonal cycles and long-term variations over the Arctic ocean were in good agreement with surface coastal measurements. Persistent methane anomalies were registered at several areas of the Arctic Ocean during autumn-winter, but not in spring-summer. Preliminary, this effect is explained by the thermal stability of the water column in summer and enhanced mixing in winter caused by seawater convection coupled with turbulent diffusion due to storms. In the 2015/2016 winter season methane concentrations around Svalbard and in other Arctic areas were record high. Annual mean methane emission was estimated from the measured anomalies. Emission from the Western Arctic seas prevails over that from ESAS (East Siberian Arctic Shelf). The total methane emission from the Arctic Ocean may be as high as~2/3 of methane from terrestrial Arctic sources.

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