New atmospheric methane observations in the Kara, Laptev, and East Siberian Seas during SWERUS-C3

Abstract:

We present a first look at a new, extensive dataset of atmospheric methane observations during the SWERUS-C3 cruise in July and August 2014. The path of the icebreaker Oden during the expedition traversed the Arctic Ocean across the Kara, Laptev and East Siberian Seas from Tromsø, Norway to Barrow, Alaska. Atmospheric methane and carbon dioxide concentrations were measured at 1 Hz resolution throughout the journey. Air was sampled at four different heights, ranging from 9 to 35 m above the sea surface. At limited stations when the ship was anchored in shallow waters of the Laptev Sea, additional in situ measurements were made at 4 m above the sea surface. Further, in-situ isotopic observations of (delta)13C-methane and (delta)D-methane were made throughout the journey. This unprecedented dataset of atmospheric methane across the outer Russian Arctic continental shelf seas may help us to make top-down estimations of methane release from the ice-covered Kara, Laptev, and East Siberian Seas to the atmosphere.