Sentinel-1 InSAR Measurements of Elevation Changes over Yedoma Uplands on Sobo-Sise Island, Lena Delta

Jie Chen,Lin Liu,Hui Lin,Guido Grosse,Frank Günther

doi:10.3390/rs10071152

Abstract

Yedoma—extremely ice-rich permafrost with massive ice wedges formed during the Late Pleistocene—is vulnerable to thawing and degradation under climate warming. Thawing of ice-rich Yedoma results in lowering of surface elevations. Quantitative knowledge about surface elevation changes helps us to understand the freeze-thaw processes of the active layer and the potential degradation of Yedoma deposits. In this study, we use C-band Sentinel-1 InSAR measurements to map the elevation changes over ice-rich Yedoma uplands on Sobo-Sise Island, Lena Delta with frequent revisit observations (as short as six or 12 days). We observe significant seasonal thaw subsidence during summer months and heterogeneous inter-annual elevation changes from 2016–17. We also observe interesting patterns of stronger seasonal thaw subsidence on elevated flat Yedoma uplands by comparing to the surrounding Yedoma slopes. Inter-annual analyses from 2016–17 suggest that our observed positive surface elevation changes are likely caused by the delayed progression of the thaw season in 2017, associated with mean annual air temperature fluctuations.

Highlights

Yedoma—extremely ice-rich permafrost with massive ice wedges formed in extensive regions in northern Siberia, Alaska, and northwest Canada during the Late Pleistocene [1,2]—is vulnerable to thawing and degradation under climate warming
As we focus on Yedoma uplands, we mask out the thermokarst basins and water bodies using this geomorphological classification [30]
The eastern regions, as well as the outer boundaries of the Yedoma uplands with lower elevation, experience less subsidence (0.5–1.0 cm)

Summary

Introduction

Yedoma—extremely ice-rich permafrost with massive ice wedges formed in extensive regions in northern Siberia, Alaska, and northwest Canada during the Late Pleistocene [1,2]—is vulnerable to thawing and degradation under climate warming. Upon surface disturbance, such as massive snowfall or precipitation, the volumetric ice content exceeds the total soil pore volume in freeze season, i.e., the formation of excess ground ice [10]. The dynamic processes between the active layer and underlying ice-rich Yedoma deposits further affect soil moisture content and vegetation growth, leading to changes in ground thermal regime and the energy exchanges between the land surface and the atmosphere [11]. These interactions potentially provide further feedbacks to surface elevation changes

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