Exploration of Thermal Bridging Through Shrub Branches in Alpine Snow

Abstract In the high Arctic, thermal bridging through frozen shrub branches has been demonstrated to cool the ground by up to 4°C during cold spells, affecting snow metamorphism and soil carbon and nutrients. In alpine conditions, the thermal conductivity contrast between shrub branches and snow is...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Florent Domine, Kevin Fourteau, Philippe Choler
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2023
Subjects:
Online Access:https://doi.org/10.1029/2023GL105100
https://doaj.org/article/f31a495745bf4c1db207f38cf0f481a7
Description
Summary:Abstract In the high Arctic, thermal bridging through frozen shrub branches has been demonstrated to cool the ground by up to 4°C during cold spells, affecting snow metamorphism and soil carbon and nutrients. In alpine conditions, the thermal conductivity contrast between shrub branches and snow is much less than in the Arctic, so that the importance of thermal bridging is uncertain. We explore this effect by monitoring ground temperature and liquid water content under green alders and under nearby alpine tundra in the Alps. During a January 2022 cold spell, the ground temperature at 5 cm depth under alders is 1.3°C colder than under alpine tundra. Ground water freezing under alders is complete, while water remains liquid under tundra. Finite element simulations reproduce the observed temperature difference between both sites, showing that thermal bridging does affect ground temperature also under Alpine conditions.