ALEXIA - Analysis Linking Arctic Methane, Carbon Release, Heat Fluxes and Sea Ice from Local to Sub-Regional Scales by Airborne Measurements

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The exchange of heat, water vapour, carbon dioxide and methane between Arctic Ocean, its sea ice cover and the polar atmosphere is still poorly known but of high importance for improved understanding of Arctic climate change. Analysis of the spatial variability and interactions of atmosphere, sea ice, ocean and biogeosphere from local to climatically relevant scales is critical to improve the performance of climate models. To fill the gap between local ground-based in situ measurements and large scale remote sensing and numerical data in the Central Arctic Ocean, an airborne data set will be obtained with helicopter based measurements during the international MOSAiC experiment, where the research vessel Polarstern will spend one year in the Arctic Ocean from September 2019 on, drifting with the sea ice above the North Pole from the Russian part of the Arctic towards Greenland. The proposal ALEXIA (Analysis Linking Arctic Methane, Carbon Release, Heat Fluxes and Sea Ice from Local to Sub-Regional Scales by Airborne Measurements) has the following aims: to investigate meteorological and surface parameters and their variability on a scale from local to a radius of 100 km around the drifting experiment, to study the impact of sea ice and synoptic conditions on heat and moisture transfer from the surface into the atmosphere, to quantify the vertical transport of methane and carbon dioxide from the ocean through the ice into the atmosphere and to distinguish the high-latitude source from long-range transport of these greenhouse gases, and to constrain the origin of the enhanced methane concentration in the shoulder seasons spring and autumn by isotopic analyses of air samples. The valuable data pool will be used for different interdisciplinary analyses for an advanced understanding of high-latitude interactions, and in the future as input and tool for numerical simulations with the overall aim to reduce uncertainty about future climate change scenarios.