A 4.5 Year‐Long Record of Svalbard Water Vapor Isotopic Composition Documents Winter Air Mass Origin

• Published in: Journal of Geophysical Research: Atmospheres
• Main Authors: Leroy‐Dos Santos, C., Masson‐Delmotte, V., Casado, M., Fourré, E., Steen‐Larsen, H., Maturilli, M., Orsi, A., Berchet, A., Cattani, O., Minster, B., Gherardi, J., Landais, A.
• Other Authors: Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Glaces et Continents, Climats et Isotopes Stables (GLACCIOS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Alfred Wegener Institute for Polar and Marine Research (AWI), Geophysical Institute Bergen (GFI / BiU), University of Bergen (UiB)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Arctic; Mount Zeppelin; Ny-Ålesund; Svalbard; North Atlantic; Ny Ålesund
• Online Access: https://hal.archives-ouvertes.fr/hal-03087623; https://hal.archives-ouvertes.fr/hal-03087623/document; https://hal.archives-ouvertes.fr/hal-03087623/file/Main_manuscript_final.pdf; https://doi.org/10.1029/2020JD032681

International audience From May 2014 to September 2018, a laser spectrometer analyzer provided a 4.5 years continuous record of water vapor isotopic composition at Ny‐Ålesund (8 m above sea level, a.s.l.), Svalbard. It corresponds to the longest data set published in polar regions. A comparison of this data set with a parallel similar data set obtained during 20 days by a second laser spectrometer installed near Mount Zeppelin (474 m a.s.l.) shows that this data set is representative of a regional signal. In addition, the observation of insignificant diurnal cycles in the isotopic signal compared to the strong isotopic signature of synoptic events and the comparison of simultaneous measurements in the vapor and in rain or snow samples lead to the conclusion that our record reflects a large part of the regional dynamics of the atmospheric water cycle driven by large‐scale variability. This study focuses on winters dominated by the occurrence of synoptic events associated with humidity peaks. Using statistics and back trajectories calculations, we link high humidity peaks characterized by an anticorrelation between δ18O and d‐excess in the water vapor to a rapid shift of air mass source regions from the Arctic to the North Atlantic Ocean below 60°N. On the other hand, correlation between δ18O and d‐excess may be associated with a shift of air mass sources within the Arctic. These results demonstrate the added value of long‐term water vapor isotopic monitoring to better understand the moisture origin in the Arctic and the atmospheric dynamics.