Understanding the relative importance of vertical and horizontal flow in ice-wedge polygons
<p>Ice-wedge polygons are common Arctic landforms. The future of these landforms in a warming climate depends on the bidirectional feedback between the rate of ice-wedge degradation and changes in hydrological characteristics. This work aims to better understand the relative roles of vertical...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-03-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | https://www.hydrol-earth-syst-sci.net/24/1109/2020/hess-24-1109-2020.pdf |
| Summary: | <p>Ice-wedge polygons are common Arctic landforms. The
future of these landforms in a warming climate depends on the bidirectional
feedback between the rate of ice-wedge degradation and changes in
hydrological characteristics. This work aims to better understand the
relative roles of vertical and horizontal water fluxes in the subsurface of
polygonal landscapes, providing new insights and data to test and calibrate
hydrological models. Field-scale investigations were conducted at an
intensively instrumented location on the Barrow Environmental Observatory
(BEO) near Utqiaġvik, AK, USA. Using a conservative tracer, we examined
controls of microtopography and the frost table on subsurface flow and
transport within a low-centered and a high-centered polygon. Bromide tracer
was applied at both polygons in July 2015 and transport was monitored
through two thaw seasons. Sampler arrays placed in polygon centers, rims,
and troughs were used to monitor tracer concentrations. In both polygons,
the tracer first infiltrated vertically until encountering the frost table and was then transported horizontally. Horizontal flow occurred in more
locations and at higher velocities in the low-centered polygon than in the
high-centered polygon. Preferential flow, influenced by frost table
topography, was significant between polygon centers and troughs. Estimates
of horizontal hydraulic conductivity were within the range of previous
estimates of vertical conductivity, highlighting the importance of
horizontal flow in these systems. This work forms a basis for understanding
complexity of flow in polygonal landscapes.</p> |
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| ISSN: | 1027-5606 1607-7938 |