Hydrological Impact of the New ECMWF Multi-Layer Snow Scheme

The representation of snow is a crucial aspect of land-surface modelling, as it has a strong influence on energy and water balances. Snow schemes with multiple layers have been shown to better describe the snowpack evolution and bring improvements to soil freezing and some hydrological processes. In...

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Bibliographic Details
Published in:Atmosphere
Main Authors: Zsoter, Ervin, Arduini, Gabriele, Prudhomme, Christel, Stephens, Elisabeth, Cloke, Hannah L.
Format: Article in Journal/Newspaper
Language:English
Published: Uppsala universitet, Luft-, vatten- och landskapslära 2022
Subjects:
land-surface modelling
snow scheme
hydrological processes
river discharge
surface runoff
permafrost
Oceanography
Hydrology and Water Resources
Oceanografi
hydrologi och vattenresurser
Climate Research
Klimatforskning
Online Access:http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-477770
https://doi.org/10.3390/atmos13050727
Description
Summary:The representation of snow is a crucial aspect of land-surface modelling, as it has a strong influence on energy and water balances. Snow schemes with multiple layers have been shown to better describe the snowpack evolution and bring improvements to soil freezing and some hydrological processes. In this paper, the wider hydrological impact of the multi-layer snow scheme, implemented in the ECLand model, was analyzed globally on hundreds of catchments. ERA5-forced reanalysis simulations of ECLand were coupled to CaMa-Flood, as the hydrodynamic model to produce river discharge. Different sensitivity experiments were conducted to evaluate the impact of the ECLand snow and soil freezing scheme changes on the terrestrial hydrological processes, with particular focus on permafrost. It was found that the default multi-layer snow scheme can generally improve the river discharge simulation, with the exception of permafrost catchments, where snowmelt-driven floods are largely underestimated, due to the lack of surface runoff. It was also found that appropriate changes in the snow vertical discretization, destructive metamorphism, snow-soil thermal conductivity and soil freeze temperature could lead to large river discharge improvements in permafrost by adjusting the evolution of soil temperature, infiltration and the partitioning between surface and subsurface runoff.

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