Biological and Environmental Research - Earth and Environmental System Sciences
Earth and Environmental System Modeling

Effects of Excess Ground Ice on Projections of Permafrost in a Warming Climate

TitleEffects of Excess Ground Ice on Projections of Permafrost in a Warming Climate
Publication TypeJournal Article
Year of Publication2014
AuthorsLee, Hanna, Swenson Sean C., Slater Andrew G., and Lawrence David M.
JournalEnvironmental Research Letters
Volume9
Number12
Pages124006
Abstract / Summary

In permafrost soils, 'excess ice', also referred to as ground ice, exists in amounts exceeding soil porosity in forms such as ice lenses and wedges. Here, we incorporate a simple representation of excess ice in the Community Land Model (CLM4.5) to investigate how excess ice affects projected permafrost thaw and associated hydrologic responses. We initialize spatially explicit excess ice obtained from the Circum-Arctic Map of Permafrost and Ground-Ice Conditions. The excess ice in the model acts to slightly reduce projected soil warming by about 0.35 °C by 2100 in a high greenhouse gas emissions scenario. The presence of excess ice slows permafrost thaw at a given location with about a 10 year delay in permafrost thaw at 3 m depth at most high excess ice locations. The soil moisture response to excess ice melt is transient and depends largely on the timing of thaw with wetter/saturated soil moisture conditions persisting slightly longer due to delayed post-thaw drainage. Based on the model projections of excess ice melt, we can estimate spatially explicit gridcell mean surface subsidence with values ranging up to 0.5 m by 2100 depending on the initial excess ice content and the extent of melt.

URLhttps://doi.org/10.1088/1748-9326/9/12/124006
DOI10.1088/1748-9326/9/12/124006
Journal: Environmental Research Letters
Year of Publication: 2014
Volume: 9
Number: 12
Pages: 124006
Publication Date: 12/2014

In permafrost soils, 'excess ice', also referred to as ground ice, exists in amounts exceeding soil porosity in forms such as ice lenses and wedges. Here, we incorporate a simple representation of excess ice in the Community Land Model (CLM4.5) to investigate how excess ice affects projected permafrost thaw and associated hydrologic responses. We initialize spatially explicit excess ice obtained from the Circum-Arctic Map of Permafrost and Ground-Ice Conditions. The excess ice in the model acts to slightly reduce projected soil warming by about 0.35 °C by 2100 in a high greenhouse gas emissions scenario. The presence of excess ice slows permafrost thaw at a given location with about a 10 year delay in permafrost thaw at 3 m depth at most high excess ice locations. The soil moisture response to excess ice melt is transient and depends largely on the timing of thaw with wetter/saturated soil moisture conditions persisting slightly longer due to delayed post-thaw drainage. Based on the model projections of excess ice melt, we can estimate spatially explicit gridcell mean surface subsidence with values ranging up to 0.5 m by 2100 depending on the initial excess ice content and the extent of melt.

DOI: 10.1088/1748-9326/9/12/124006
Citation:
Lee, H, SC Swenson, AG Slater, and DM Lawrence.  2014.  "Effects of Excess Ground Ice on Projections of Permafrost in a Warming Climate."  Environmental Research Letters 9(12): 124006.  https://doi.org/10.1088/1748-9326/9/12/124006.