Gilbert A., Vincent C., Six D., Wagnon Patrick, Piard L., Ginot Patrick. (2014). Modeling near-surface firn temperature in a cold accumulation zone (Col du Dome, French Alps) : from a physical to a semi-parameterized approach. Cryosphere, 8 (2), p. 689-703. ISSN 1994-0416.
Titre du document
Modeling near-surface firn temperature in a cold accumulation zone (Col du Dome, French Alps) : from a physical to a semi-parameterized approach
Gilbert A., Vincent C., Six D., Wagnon Patrick, Piard L., Ginot Patrick
Source
Cryosphere, 2014,
8 (2), p. 689-703 ISSN 1994-0416
Analysis of the thermal regime of glaciers is crucial for glacier hazard assessment, especially in the context of a changing climate. In particular, the transient thermal regime of cold accumulation zones needs to be modeled. A modeling approach has therefore been developed to determine this thermal regime using only near-surface boundary conditions coming from meteorological observations. In the first step, a surface energy balance (SEB) model accounting for water percolation and radiation penetration in firn was applied to identify the main processes that control the subsurface temperatures in cold firn. Results agree well with subsurface temperatures measured at Col du Dome (4250m above sea level (a.s.l.)), France. In the second step, a simplified model using only daily mean air temperature and potential solar radiation was developed. This model properly simulates the spatial variability of surface melting and subsurface firn temperatures and was used to accurately reconstruct the deep borehole temperature profiles measured at Col du Dome. Results show that percolation and refreezing are efficient processes for the transfer of energy from the surface to underlying layers. However, they are not responsible for any higher energy uptake at the surface, which is exclusively triggered by increasing energy flux from the atmosphere due to SEB changes when surface temperatures reach 0 degrees C. The resulting enhanced energy uptake makes cold accumulation zones very vulnerable to air temperature rise.
