Abstract
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 Utqiagvik, 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.
| Original language | English |
|---|---|
| Pages (from-to) | 1109-1129 |
| Number of pages | 21 |
| Journal | Hydrology and Earth System Sciences |
| Volume | 24 |
| Issue number | 3 |
| DOIs | |
| State | Published - Mar 10 2020 |
| Externally published | Yes |
Funding
Acknowledgements. This work was supported by the DOE Office of Science, Biological and Environmental Research program and the Next Generation Ecosystem Experiment (NGEE-Arctic) project. We are grateful to George Perkins, Emily Kluk, and the staff of the GGRL at Los Alamos National Laboratory for their work in sample analysis. We thank Anna Liljedahl for early contributions to experimental design and for the use of preexisting infrastructure. We also thank Lauren Charsley-Groffman for GIS work and her work in the field. We thank John Peterson for helping GPR data acquisition and processing. We acknowledge Vladimir Romanovsky for his pictures of frozen cores and Bob Busey for the use of his meteorological data. This research was undertaken by the Los Alamos National Laboratory under contract to the Department of Energy (contract number DE-AC52-06NA25396).
| Funders | Funder number |
|---|---|
| Biological and Environmental Research program | |
| DOE Office of Science | |
| U.S. Department of Energy | DE-AC52-06NA25396 |
| Los Alamos National Laboratory |