ALBERT

Description: Local evaporation in the Arctic is likely to increase with sea-ice retreat in the context of climate change. In parallel, the transport of moisture from the North Atlantic may also increase, especially in cases of weak polar vortex, associated to blocking over the Norwegian Sea and fast vapor transport into the Arctic. In order to evaluate the contribution of different sources to the moisture budget in the Arctic, a tool is needed to track the transport of vapor in the region. Here, we combine in-situ measurements of vapor isotope composition to analysis of back- trajectories, to reconstruct the pathway of vapor transport in different synoptic situations during two cruises North of Svalbard in 2018 and 2019. During the hot summer of 2018 in Europe, high dD values are observed in the Arctic. These high values could result from intense evaporation during the heat wave followed by quick transport into the Arctic. Indeed, back-trajectories indicate northern Europe as a dominant contributor to the moisture sampled during this period. During summer 2019, we observe wide oscillations of dD values depending on the moisture origin. An atmospheric river is sampled on the 29th of August 2019, that shows that Atlantic (southerly) air is characterized by high humidity and high dD values, opposite to Arctic (northerly) air. The secondary parameter d-excess varies in opposition to dD. This study highlights the potential of isotopes for identifying moisture sources around the Arctic.