Simulating ice layer formation under the presence of preferential flow in layered snowpacks
For physics-based snow cover models, simulating the formation of dense ice layers inside the snowpack has been a long-time challenge. Their formation is considered to be tightly coupled to the presence of preferential flow, which is assumed to happen through flow fingering. Recent laboratory experim...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-11-01
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| Series: | The Cryosphere |
| Online Access: | http://www.the-cryosphere.net/10/2731/2016/tc-10-2731-2016.pdf |
| _version_ | 1818562751994265600 |
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| author | N. Wever S. Würzer C. Fierz M. Lehning |
| author_facet | N. Wever S. Würzer C. Fierz M. Lehning |
| author_sort | N. Wever |
| collection | DOAJ |
| description | For physics-based snow cover models, simulating the formation of dense ice
layers inside the snowpack has been a long-time challenge. Their formation is
considered to be tightly coupled to the presence of preferential flow, which
is assumed to happen through flow fingering. Recent laboratory experiments
and modelling techniques of liquid water flow in snow have advanced the
understanding of conditions under which preferential flow paths or flow
fingers form. We propose a modelling approach in the one-dimensional,
multilayer snow cover model SNOWPACK for preferential flow that is based on
a dual domain approach. The pore space is divided into a part that represents
matrix flow and a part that represents preferential flow. Richards' equation
is then solved for both domains and only water in matrix flow is subjected to
phase changes. We found that preferential flow paths arriving at a layer
transition in the snowpack may lead to ponding conditions, which we used to
trigger a water flow from the preferential flow domain to the matrix domain.
Subsequent refreezing then can form dense layers in the snowpack that
regularly exceed 700 kg m<sup>−3</sup>. A comparison of simulated density
profiles with biweekly snow profiles made at the Weissfluhjoch measurement
site at 2536 m altitude in the Eastern Swiss Alps for 16 snow seasons showed
that several ice layers that were observed in the field could be reproduced.
However, many profiles remain challenging to simulate. The prediction of the
early snowpack runoff also improved under the consideration of preferential
flow. Our study suggests that a dual domain approach is able to describe the
net effect of preferential flow on ice layer formation and liquid water flow
in snow in one-dimensional, detailed, physics-based snowpack models, without
the need for a full multidimensional model. |
| first_indexed | 2024-12-14T01:07:52Z |
| format | Article |
| id | doaj.art-075b9c5f11f048aa927ce1381d7fff61 |
| institution | Directory Open Access Journal |
| issn | 1994-0416 1994-0424 |
| language | English |
| last_indexed | 2024-12-14T01:07:52Z |
| publishDate | 2016-11-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | The Cryosphere |
| spelling | doaj.art-075b9c5f11f048aa927ce1381d7fff612022-12-21T23:22:54ZengCopernicus PublicationsThe Cryosphere1994-04161994-04242016-11-011062731274410.5194/tc-10-2731-2016Simulating ice layer formation under the presence of preferential flow in layered snowpacksN. Wever0S. Würzer1C. Fierz2M. Lehning3École Polytechnique Fédérale de Lausanne (EPFL), School of Architecture, Civil and Environmental Engineering, Lausanne, SwitzerlandÉcole Polytechnique Fédérale de Lausanne (EPFL), School of Architecture, Civil and Environmental Engineering, Lausanne, SwitzerlandWSL Institute for Snow and Avalanche Research SLF, Davos, SwitzerlandWSL Institute for Snow and Avalanche Research SLF, Davos, SwitzerlandFor physics-based snow cover models, simulating the formation of dense ice layers inside the snowpack has been a long-time challenge. Their formation is considered to be tightly coupled to the presence of preferential flow, which is assumed to happen through flow fingering. Recent laboratory experiments and modelling techniques of liquid water flow in snow have advanced the understanding of conditions under which preferential flow paths or flow fingers form. We propose a modelling approach in the one-dimensional, multilayer snow cover model SNOWPACK for preferential flow that is based on a dual domain approach. The pore space is divided into a part that represents matrix flow and a part that represents preferential flow. Richards' equation is then solved for both domains and only water in matrix flow is subjected to phase changes. We found that preferential flow paths arriving at a layer transition in the snowpack may lead to ponding conditions, which we used to trigger a water flow from the preferential flow domain to the matrix domain. Subsequent refreezing then can form dense layers in the snowpack that regularly exceed 700 kg m<sup>−3</sup>. A comparison of simulated density profiles with biweekly snow profiles made at the Weissfluhjoch measurement site at 2536 m altitude in the Eastern Swiss Alps for 16 snow seasons showed that several ice layers that were observed in the field could be reproduced. However, many profiles remain challenging to simulate. The prediction of the early snowpack runoff also improved under the consideration of preferential flow. Our study suggests that a dual domain approach is able to describe the net effect of preferential flow on ice layer formation and liquid water flow in snow in one-dimensional, detailed, physics-based snowpack models, without the need for a full multidimensional model.http://www.the-cryosphere.net/10/2731/2016/tc-10-2731-2016.pdf |
| spellingShingle | N. Wever S. Würzer C. Fierz M. Lehning Simulating ice layer formation under the presence of preferential flow in layered snowpacks The Cryosphere |
| title | Simulating ice layer formation under the presence of preferential flow in layered snowpacks |
| title_full | Simulating ice layer formation under the presence of preferential flow in layered snowpacks |
| title_fullStr | Simulating ice layer formation under the presence of preferential flow in layered snowpacks |
| title_full_unstemmed | Simulating ice layer formation under the presence of preferential flow in layered snowpacks |
| title_short | Simulating ice layer formation under the presence of preferential flow in layered snowpacks |
| title_sort | simulating ice layer formation under the presence of preferential flow in layered snowpacks |
| url | http://www.the-cryosphere.net/10/2731/2016/tc-10-2731-2016.pdf |
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