The hydrology of Arctic landscapes with differing ice wedge polygon type through field measurements and modeling

Ice wedge polygons are common in landscapes underlain by permafrost. Still, their role on watershed-scale hydrology is constrained. We combined field measurements with thermal- and hydrologic modeling to assess the effect of ice wedge polygon type on landscape-scale hydrologic fluxes and stores. The physically-based model WaSiM was applied to airborne LiDAR and schematic DEMs, and forced by climate data from the Biocomplexity Experiment, Barrow, Alaska. Simulations and field measurements were concentrated to four sites, i.e. landscape types: high-centered, low-centered, and two transition polygon sites (the latter having both low-centers and troughs). Model simulations suggest that low-centered polygons, through elevated rims, reduce runoff while increasing evapotranspiration and water storage. The high-centered polygon landscape favors runoff, while storage and evapotranspiration drastically decrease. Continuous field measurements in neighboring, individual ice wedge polygons presents drastically different seasonal variability in water tables between study sites, despite the same landscape-scale end-of-winter snowpack water storage. It is evident from the field and modeling analyses that microtopography plays an important role on low-gradient Arctic wetland watershed-scale hydrology. Further, the fine microtopographical variability results in hydrologic characteristics that can present important geomorphological feedbacks. A shift in ice wedge polygon type could potentially dominate the initial effects of altered climate on Arctic wetland hydrology.