气候变化领域集成服务门户(CCPortal): Microtopographic control on the ground thermal regime in ice wedge polygons

CCPortal

DOI	10.5194/tc-12-1957-2018
	Microtopographic control on the ground thermal regime in ice wedge polygons
	Abolt C.J.; Young M.H.; Atchley A.L.; Harp D.R.
发表日期	2018
ISSN	19940416
卷号	12 期号:6
英文摘要	The goal of this research is to constrain the influence of ice wedge polygon microtopography on near-surface ground temperatures. Ice wedge polygon microtopography is prone to rapid deformation in a changing climate, and cracking in the ice wedge depends on thermal conditions at the top of the permafrost; therefore, feedbacks between microtopography and ground temperature can shed light on the potential for future ice wedge cracking in the Arctic. We first report on a year of sub-daily ground temperature observations at 5 depths and 9 locations throughout a cluster of low-centered polygons near Prudhoe Bay, Alaska, and demonstrate that the rims become the coldest zone of the polygon during winter, due to thinner snowpack. We then calibrate a polygon-scale numerical model of coupled thermal and hydrologic processes against this dataset, achieving an RMSE of less than 1.1°C between observed and simulated ground temperature. Finally, we conduct a sensitivity analysis of the model by systematically manipulating the height of the rims and the depth of the troughs and tracking the effects on ice wedge temperature. The results indicate that winter temperatures in the ice wedge are sensitive to both rim height and trough depth, but more sensitive to rim height. Rims act as preferential outlets of subsurface heat; increasing rim size decreases winter temperatures in the ice wedge. Deeper troughs lead to increased snow entrapment, promoting insulation of the ice wedge. The potential for ice wedge cracking is therefore reduced if rims are destroyed or if troughs subside, due to warmer conditions in the ice wedge. These findings can help explain the origins of secondary ice wedges in modern and ancient polygons. The findings also imply that the potential for re-establishing rims in modern thermokarst-affected terrain will be limited by reduced cracking activity in the ice wedges, even if regional air temperatures stabilize. © Author(s) 2018.
学科领域	air temperature; climate change; ice cover; numerical model; permafrost; polygon; snowpack; thermal regime; thermokarst; Alaska; Arctic; Prudhoe Bay; United States
语种	英语
scopus关键词	air temperature; climate change; ice cover; numerical model; permafrost; polygon; snowpack; thermal regime; thermokarst; Alaska; Arctic; Prudhoe Bay; United States
来源期刊	Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/119133
作者单位	Department of Geological Sciences, University of Texas at Austin, Austin, TX, United States; Bureau of Economic Geology, University of Texas at Austin, Austin, TX, United States; Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, United States
推荐引用方式 GB/T 7714	Abolt C.J.,Young M.H.,Atchley A.L.,et al. Microtopographic control on the ground thermal regime in ice wedge polygons[J],2018,12(6).
APA	Abolt C.J.,Young M.H.,Atchley A.L.,&Harp D.R..(2018).Microtopographic control on the ground thermal regime in ice wedge polygons.Cryosphere,12(6).
MLA	Abolt C.J.,et al."Microtopographic control on the ground thermal regime in ice wedge polygons".Cryosphere 12.6(2018).