Motion of dust particles in dry snow under temperature gradient metamorphism

• Published in: The Cryosphere
• Main Authors: Hagenmuller, Pascal, Flin, Frederic, Dumont, Marie, Tuzet, François, Peinke, Isabel, Lapalus, Philippe, Dufour, Anne, Roulle, Jacques, Pézard, Laurent, Voisin, Didier, Andò, Edward, Rolland Du Roscoat, Sabine, Charrier, Pascal
• Other Authors: Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 ), Laboratoire sols, solides, structures - risques Grenoble (3SR ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 )
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Arctic; black carbon; The Cryosphere
• Online Access: https://meteofrance.hal.science/meteo-03657903; https://meteofrance.hal.science/meteo-03657903/document; https://meteofrance.hal.science/meteo-03657903/file/tc-13-2345-2019.pdf; https://doi.org/10.5194/tc-13-2345-2019

International audience Abstract. The deposition of light-absorbing particles (LAPs) such as mineral dust and black carbon on snow is responsible for a highly effective climate forcing, through darkening of the snow surface and associated feedbacks. The interplay between post-depositional snow transformation (metamorphism) and the dynamics of LAPs in snow remains largely unknown. We obtained time series of X-ray tomography images of dust-contaminated samples undergoing dry snow metamorphism at around −2 ∘C. They provide the first observational evidence that temperature gradient metamorphism induces dust particle motion in snow, while no movement is observed under isothermal conditions. Under temperature gradient metamorphism, dust particles can enter the ice matrix due to sublimation–condensation processes and spread down mainly by falling into the pore space. Overall, such motions might reduce the radiative impact of dust in snow, in particular in arctic regions where temperature gradient metamorphism prevails.