Status: this discussion paper is a preprint. It has been under review for the journal The Cryosphere (TC). The manuscript was not accepted for further review after discussion.
New insights into the drainage of inundated Arctic polygonal tundra using fundamental hydrologic principles
Dylan R. Harp,Vitaly Zlotnik,Charles J. Abolt,Brent D. Newman,Adam L. Atchley,Elchin Jafarov,and Cathy J. Wilson
Abstract. The pathways and timing of drainage from inundated ice-wedge polygon centers in a warming climate have important implications for carbon flushing, advective heat transport, and transitions from carbon dioxide to methane dominated emissions. This research helps to understand this process by providing the first in-depth analysis of drainage from a single polygon based on fundamental hydrogeological principles. We use a recently developed analytical solution to evaluate the effects of polygon aspect ratios (radius to thawed depth) and hydraulic conductivity anisotropy (horizontal to vertical hydraulic conductivity) on drainage pathways and temporal depletion of ponded water heights of inundated ice-wedge polygon centers. By varying the polygon aspect ratio, we evaluate the effect of polygon size (width), inter-annual increases in active layer thickness, and seasonal increases in thaw depth on drainage. One of the primary insights from the model is that most inundated ice-wedge polygon drainage occurs along an annular region of the polygon center near the rims. This implies that inundated polygons are most intensely flushed by drainage in an annular region along their horizontal periphery, with implications for transport of nutrients (such as dissolved organic carbon) and advection of heat towards ice wedge tops. The model indicates that polygons with large aspect ratios and high anisotropy will have the most distributed drainage. Polygons with large aspect ratio and low anisotropy will have their drainage most focused near the their periphery and will drain most slowly. Polygons with small aspect ratio and high anisotropy will drain most quickly.
How to cite. Harp, D. R., Zlotnik, V., Abolt, C. J., Newman, B. D., Atchley, A. L., Jafarov, E., and Wilson, C. J.: New insights into the drainage of inundated Arctic polygonal tundra using fundamental hydrologic principles, The Cryosphere Discuss. [preprint], https://doi.org/10.5194/tc-2020-100, 2020.
Received: 08 Apr 2020 – Discussion started: 05 May 2020
Polygon shaped land forms present in relatively flat Arctic tundra result in complex landscape scale water drainage. The drainage pathways and the time to transition from inundated conditions to drained have important implications for heat and carbon transport. Using fundamental hydrologic principles, we investigate the drainage pathways and timing of individual polygons providing insights into the effects of polygon geometry and preferential flow direction on drainage pathways and timing.
Polygon shaped land forms present in relatively flat Arctic tundra result in complex landscape...