Understanding inundation and drainage patterns of ice-wedge polygons

Abstract:

As Arctic polygonal tundra transitions under a warming climate, the hydrology of ice-wedge polygon inundation and drainage patterns will change. Considering the ice-wedge polygon as a fundamental hydrologic unit of polygonal tundra, understanding individual polygon inundation and drainage patterns is required to understand the hydrologic response of the overall polygonal tundra landscape. Using idealized conceptualizations of individual polygons in numerical and analytical models, we investigate the effects of thawed layer geometry (polygon width and thaw layer depth) and hydraulic conductivity anisotropy to understand inundation and drainage patterns under different scenarios. Using the models, we test hypothesis about ice-wedge polygon hydrology based on the ability to calibrate model parameters to match water levels measured within polygonal tundra at the Barrow Environmental Observatory. These results will indicate which regions of polygons transmit the most fluid and are therefore the most well flushed of nutrients, versus regions where the water primarily stagnates. Flow patterns will also indicate advective heat transport pathways potentially bringing warm surface water towards frozen ground, like ice-wedge tops. The results will also enhance our understanding of the hydraulic connection between polygon centers and troughs providing indications for the potential to transport dissolved organic carbon and other nutrients from the polygon thawed layer to the surface water of the trough.