Modeling Natural Tritium in Precipitation and its Dependence on Decadal Solar Activity Variations Using the Atmospheric General Circulation Model MIROC5‐Iso

• Published in: Journal of Geophysical Research: Atmospheres
• Main Authors: Cauquoin, Alexandre, Fourré, Élise, Landais, Amaelle, Okazaki, Atsushi, Yoshimura, Kei
• Other Authors: Institute of Industrial Science (IIS), The University of Tokyo (UTokyo), Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), 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)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Glaces et Continents, Climats et Isotopes Stables (GLACCIOS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Hirosaki University
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2024
• Subjects: Natural Tritium; Precipitation; Solar Activity Variations; Modeling; Atmospheric CGM; MIROC5‐Iso; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Antarc*; Antarctic; Antarctica; Greenland; North Atlantic; North Atlantic oscillation
• Online Access: https://hal.science/hal-04488257; https://hal.science/hal-04488257/document; https://hal.science/hal-04488257/file/JGR%20Atmospheres%20-%202024%20-%20Cauquoin%20-%20Modeling%20Natural%20Tritium%20in%20Precipitation%20and%20its%20Dependence%20on%20Decadal%20Solar%20Activity.pdf; https://doi.org/10.1029/2023jd039745

International audience Modeling tritium content in water presents a meaningful way to evaluate the representation of the water cycle in climate models as it traces fluxes within and between the reservoirs involved in the water cycle (stratosphere, troposphere, and ocean). In this study, we present the implementation of natural tritium in water in the atmospheric general circulation model (AGCM) MIROC5-iso and its simulation for the period 1979-2018. Owing to recently published tritium production calculations, we were able to investigate, for the first time, the influence of natural tritium production related to the 11-yr solar cycle on tritium in precipitation. MIROC5-iso correctly simulates continental, latitudinal, and altitude effects on tritium in precipitation. The seasonal tritium content peaks, linked to stratosphere-troposphere exchanges, are accurately simulated in terms of timing, even though MIROC5-iso underestimates the amplitude of the changes. Decadal tritium concentration variations in precipitation owing to the 11-yr solar cycle are well simulated in MIROC5-iso, in agreement with the observations at Vostok in Antarctica for example, Finally, our simulations revealed that the internal climate variability plays an important role in tritium in polar precipitation. Owing to its influence on the south polar vortex, the Southern Annular Mode enhances the effect of the production component on tritium in East Antarctic precipitation. In Greenland, we found an east-west contrast in the detection of the 11-yr solar cycle in tritium in precipitation owing to the influence of the North Atlantic Oscillation on humidity conditions.