Thermokarst Development Detected from High-Definition Topographic Data in Central Yakutia

Hitoshi Saito,Yoshihiro Iijima,Viktor Kunitsky,Alexander Fedorov,Nikolay Basharin

doi:10.3390/rs10101579

Abstract

Eastern Siberia is characterized by widespread permafrost thawing and subsequent thermokarst development. Estimation of the impacts of the predicted rise in precipitation and air temperatures under climate change requires quantitative knowledge about the spatial distribution of thermokarst development. In the last few years, unmanned aerial systems (UAS) and structure-from-motion multi-view stereo (SfM-MVS) photogrammetry attracted a tremendous amount of interest for acquiring high-definition topographic data. This study detected characteristics of thermokarst landforms using UAS and SfM-MVS photogrammetry at a disused airfield (3.0 ha) and for arable land that was previously used for farming (6.3 ha) in the Churapcha area, located on the right bank of the Lena River in central Yakutia. Orthorectified photographs and digital terrain models with spatial resolutions of 4.0 cm and 8.0 cm, respectively, were obtained for this study. At the disused airfield site and the abandoned arable land, 174 and 867 high-centered polygons that developed after the 1990s were detected, respectively. The data showed that the average diameter and average area of the polygons at the disused airfield site were 11.6 m and 111.2 m2, respectively, while those of the polygons in the abandoned arable land were 7.4 m and 46.8 m2, respectively. The abandoned arable land was characterized by smaller polygons and a higher polygon density. The differences in polygon size for the abandoned arable land and the disused airfield site indicate a difference in the ice wedge distributions and thermokarst developments. The subsidence rate was estimated as 2.1 cm/year for the disused airfield site and 3.9 cm/year for the abandoned arable land.

Highlights

The term “thermokarst” refers to a process that produces characteristic landforms as a result of the thawing of ice-rich permafrost or the melting of massive ice [1,2]
Comparison of the DTMs and the ground-based leveling shows that the data obtained from the unmanned aerial systems (UAS) and structure-from-motion multi-view stereo (SfM-MVS) photogrammetry are a good representation the topography (Figure 3e), the DTMs have an uncertainty of a few tens of centimeters in the SfM-MVS photogrammetry
This study showed the availability of the UAS and SfM-MVS photogrammetry technique to measure thermokarst landforms

Summary

Introduction

The term “thermokarst” refers to a process that produces characteristic landforms as a result of the thawing of ice-rich permafrost or the melting of massive ice [1,2]. Thermokarst research is important because it can be used to estimate permafrost degradation. Thermokarst formation is associated with landscape disturbances and climate change [3]. Thermokarst is most active in open natural and anthropogenic landscapes. The destruction of the transient layer, which strongly protects frozen permafrost from thawing [4], resulted in increased thermokarst landform development [5]. Several field studies reported the activation of topographical subsidence along with thermokarst development in continuous permafrost zones. The vulnerability of permafrost to degradation induced by thermokarst subsidence depends on the degree of surface disturbance (e.g., from wild fires [6], clear-cutting [7], and anthropogenic land use [8,9]) and the subsequent deepening of the active layer thickness

Methods

Results

Discussion

Conclusion