Isotope measurements of the Arctic water cycle and exchange processes between seawater, sea ice, and snow during MOSAiC

• Main Authors: Mellat, Moein, Werner, Martin, Brunello, Camilla Francesca, Bauch, Dorothea, Damm, Ellen, Nomura, Daiki, D'Angelo, Alessandra, Welker, Jeffrey M., Schneebeli, Martin, Meyer, Hanno
• Format: Conference Object
• Language: unknown
• Published: 2022
• Subjects: Arctic; Greenland; Arctic Basin; Ice Sheet; Sea ice
• Online Access: https://epic.awi.de/id/eprint/56243/; https://epic.awi.de/id/eprint/56243/1/Moein_Mellat_EGU_22.pdf; https://doi.org/10.5194/egusphere-egu22-7062; https://hdl.handle.net/10013/epic.9a7a553d-b464-489f-97ae-281c47c3c5c5; https://hdl.handle.net/

For the past two decades, the Arctic water cycle changed rapidly due to surface air temperatures (SATs) increasing at twice the global rate. Terrestrial ice (i.e. Greenland Ice Sheet) and marine sea-ice loss, alterations of ocean circulation patterns, and shifting atmospheric moisture sources and transport are some of the most pronounced changes caused by the Arctic amplification, fostering increased humidity levels. Stable water isotopes (δ18O, δ2H) and the secondary parameter d-excess are valuable tracers for hydrological changes, including how these shifts may affect the global climate system. However, it is only recently that we are using precipitation and water vapor networks to resolve water isotope patterns and processes in the Arctic. However, a fully coordinated study of the entire water cycle attributes year-long including sea ice, ocean water, vapor, and precipitation has until recently has been absent. The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition provided a unique opportunity to collect, analyze, and synthesize discrete samples of the different hydrological compartments in the central Arctic, covering a complete one-year seasonal cycle using a combination of ship-based, the pan-Arctic Water Isotope Network (PAPIN). These observations can lead to new insights into coupled ocean-atmosphere climate processes operating in the Arctic, especially during extreme events, sea ice formation, sea ice retreat, and during a dichotomy of synoptic weather patterns over the MOSAiC-year. We present the isotopic traits of more than 2,200 discrete samples (i.e., seawater, sea ice, snow, brines, frost flowers, lead ice, ridge ice, and precipitation) collected during MOSAiC. Snow has the most depleted δ18O values (-16.3 ± 9.1‰; the number of samples N=306), whereas seawater is the most enriched δ18O compartment (-1.5 ± 0.9‰; N=302) of the Arctic water cycle. Precipitation throughout the Arctic Basin varied from -10‰ to -35‰. Snow profiles are gradually enriched in δ18O ...